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Surgery_Schwartz. Radiation (approximately 4000 cGy) is also an integral part of the manage-ment of patients with Hodgkin’s disease. It is now known that a history of exposure to low-dose ionizing radiation to the thyroid gland places the patient at increased risk for developing thyroid cancer. The risk increases linearly from 6.5 to 2000 cGy, beyond which the incidence declines as the radiation causes destruc-tion of the thyroid tissue. The risk is maximum 20 to 30 years after exposure, but these patients require lifelong monitoring. During the nuclear fallout from Chernobyl in 1986, 131I release was accompanied by a marked increase in the incidence of both benign and malignant thyroid lesions noted within 4 years of exposure, particularly in children.17 Most thyroid carcinomas following radiation exposure are papillary, and some of these cancers with a solid type of histology and presence of RET/PTC translocations appear to be more aggressive. In general, there is a 40% chance that patients


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Surgery_Schwartz. exposure are papillary, and some of these cancers with a solid type of histology and presence of RET/PTC translocations appear to be more aggressive. In general, there is a 40% chance that patients presenting with a thyroid nodule and a history of radiation have thyroid cancer. Of those patients who have thyroid cancer, the cancer is located in the dominant nodule in 60% of patients, but in the remaining 40% of patients, the cancer is in another nodule in the thyroid gland.Table 38-3Etiology of nontoxic goiterCLASSIFICATIONSPECIFIC ETIOLOGYEndemicIodine deficiency, dietary goitrogens (cassava, cabbage)MedicationsIodide, amiodarone, lithiumThyroiditisSubacute, chronic (Hashimoto’s)FamilialImpaired hormone synthesis from enzyme defectsNeoplasmAdenoma, carcinomaResistance to thyroid hormone—Brunicardi_Ch38_p1625-p1704.indd 164101/03/19 11:20 AM 1642SPECIFIC CONSIDERATIONSPART IIABFigure 38-13. A. Retrosternal extension of a large goiter may result in impeded flow in the superior vena


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Surgery_Schwartz. 164101/03/19 11:20 AM 1642SPECIFIC CONSIDERATIONSPART IIABFigure 38-13. A. Retrosternal extension of a large goiter may result in impeded flow in the superior vena cava, leading to dilated veins over the chest wall. This may become more prominent when patients raise their arms above the head—Pemberton’s sign. B. Computed tomography scan demonstrating retrosternal extension and consequent tracheal deviation and compression from a large goiter.Brunicardi_Ch38_p1625-p1704.indd 164201/03/19 11:20 AM 1643THYROID, PARATHYROID, AND ADRENALCHAPTER 38Family History A family history of thyroid cancer is a risk factor for the development of both medullary and nonmedullary thyroid cancer. Familial MTCs occur in isolation or in associa-tion with other tumors as part of multiple endocrine neoplasia type 2 (MEN2) syndromes. Nonmedullary thyroid cancers can occur in association with other known familial cancer syn-dromes such as Cowden’s syndrome, Werner’s syndrome (adult progeroid syndrome),


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Surgery_Schwartz. type 2 (MEN2) syndromes. Nonmedullary thyroid cancers can occur in association with other known familial cancer syn-dromes such as Cowden’s syndrome, Werner’s syndrome (adult progeroid syndrome), familial adenomatous polyposis, and DICER 1 (Table 38-4). Nonmedullary thyroid cancers can also occur independently of these syndromes as the predominant tumors in the families, and in fact nonsyndromic FNMTC accounts for 95% of cases. The definition of familial nonmedul-lary thyroid cancer (FNMTC) is variable across the literature; however, in most studies, it is defined by the presence of two or more first-degree relatives with follicular cell–derived cancers. FNMTC is now recognized as a distinct clinical entity associated with a high incidence of multifocal tumors and benign thyroid nodules. Some studies report that these patients have higher locoregional recurrence rates and consequently shorter disease-free survival. Several candidate chromosomal loci that predispose to these tumors


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Surgery_Schwartz. Some studies report that these patients have higher locoregional recurrence rates and consequently shorter disease-free survival. Several candidate chromosomal loci that predispose to these tumors have been identified, includ-ing MNG1 (14q32), thyroid carcinoma with oxphilia (TCO, on 19p13.2), fPTC/papillary renal neoplasia (PRN, on 1q21), NMTC1 (2q21), and FTEN (8p23.1-p22). Susceptibility genes include SRGAP1 (12q14), TITF-1/NKX2.1 (14q13), FOXE1 (9q22), and the telomere-telomerase complex.18Physical Examination. The thyroid gland is best palpated from behind the patient and with the neck in mild extension. The cricoid cartilage is an important landmark, as the isthmus is situated just below it. Nodules that are hard, gritty, or fixed to surrounding structures such as the trachea or strap muscles are more likely to be malignant. The cervical chain of lymph nodes should be assessed as well as the nodes in the posterior triangle.Diagnostic Investigations. An algorithm for the workup


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Surgery_Schwartz. muscles are more likely to be malignant. The cervical chain of lymph nodes should be assessed as well as the nodes in the posterior triangle.Diagnostic Investigations. An algorithm for the workup of a solitary thyroid nodule is shown in Fig. 38-14.Fine-Needle Aspiration Biopsy FNAB has become the single most important test in the evaluation of thyroid masses and can be performed with or without ultrasound guidance. Ultrasound guidance is recommended for nodules that are difficult to pal-pate, for cystic or solid-cystic nodules that recur after the initial aspiration, and for multinodular goiters. A 23-gauge needle is inserted into the thyroid mass, and several passes are made while aspirating the syringe. After releasing the suction on the syringe, the needle is withdrawn and the cells are immediately placed on prelabeled dry glass slides; some are immersed in a 70% alcohol solution while others are air dried. A sample of the aspirate is also placed in a 90% alcohol solution for


Surgery_Schwartz

Surgery_Schwartz. are immediately placed on prelabeled dry glass slides; some are immersed in a 70% alcohol solution while others are air dried. A sample of the aspirate is also placed in a 90% alcohol solution for cytospin or cell pellet. The slides are stained by Papanicolaou’s or Wright’s stains and examined under the microscope. If a bloody aspirate is obtained, the patient should be repositioned in a more upright position and the biopsy repeated with a finer (25to 30-gauge) needle.After FNAB, the majority of nodules can be classified into several categories that determine further management. To address the issue of variability in the terminology of fine-needle aspiration (FNA), the National Cancer Institute (NCI) hosted the “NCI Thyroid Fine Needle Aspiration State of the Science Conference,” which then defined the Bethesda criteria for thyroid FNA.19 Accordingly, optimum cytology specimens should have at least six follicles each containing at least 10 to 15 cells from at least two aspirates.The


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Surgery_Schwartz. defined the Bethesda criteria for thyroid FNA.19 Accordingly, optimum cytology specimens should have at least six follicles each containing at least 10 to 15 cells from at least two aspirates.The FNA is classified as “nondiagnostic or unsatisfac-tory” in 2% to 20% of cases and typically results from a virtu-ally acellular specimen, cyst fluid, or the presence of blood or clotting artifact. The risk of malignancy in this setting ranges from 1% to 4%, and reaspiration under ultrasound guidance is recommended. A “benign” result is obtained in 60% to 70% of thyroid FNAs. The most common lesion in this setting is a follicular nodule (includes adenomatoid nodule, colloid nodule, and follicular adenoma). Other diagnoses include lymphocytic (Hashimoto’s) thyroiditis and granulomatous thyroiditis. False-negative results are reported in up to 3% of cases, and follow-up is recommended. A result of “atypia of unknown significance (AUS) or follicular lesion of unknown significance (FLUS)” is


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Surgery_Schwartz. False-negative results are reported in up to 3% of cases, and follow-up is recommended. A result of “atypia of unknown significance (AUS) or follicular lesion of unknown significance (FLUS)” is obtained in 3% to 6% of biopsies. The risk of malignancy in this scenario is difficult to determine; however, it is thought to be in the range of 5% to 15%. Clinical correlation and a repeat FNA are recommended for AUS lesions (which often results in 23Table 38-4Familial cancer syndromes involving nonmedullary thyroid cancerSYNDROMEGENEMANIFESTATIONTHYROID TUMORCowden’s syndromePTENIntestinal hamartomas, benign and malignant breast tumorsFTC, rarely PTC and Hürthle cell tumorsFAPAPCColon polyps and cancer, duodenal neoplasms, desmoidsPTC cribriform growth patternWerner’s syndromeWRNAdult progeroid syndromePTC, FTC, anaplastic cancerCarney complex type 1PRKAR1αCutaneous and cardiac myxomas, breast and adrenal tumorsPTC, FTCMcCune-Albright syndromeGNAS1Polyostotic fibrous dysplasia, endocrine


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Surgery_Schwartz. syndromePTC, FTC, anaplastic cancerCarney complex type 1PRKAR1αCutaneous and cardiac myxomas, breast and adrenal tumorsPTC, FTCMcCune-Albright syndromeGNAS1Polyostotic fibrous dysplasia, endocrine abnormalities, café-au-lait spotsPTC clear cellDICER 1 syndrome Pleuropulmonary blastoma, cystic nephroma, ovarian sex cord-stromal tumorsMultinodular goiter, thyroid cancerFAP = familial adenomatous polyposis; FTC = follicular thyroid cancer; PTC = papillary thyroid cancer.Brunicardi_Ch38_p1625-p1704.indd 164301/03/19 11:20 AM 1644SPECIFIC CONSIDERATIONSPART IIa more definitive interpretation), although clinical observation or surgery may be appropriate because of worrisome clinical or ultrasound findings. The category of “follicular neoplasm” is intended to identify nodules that might be follicular carcinomas. The term suspicious for a follicular neoplasm is preferred by some laboratories for this category because up to 35% of cases turn out not to be neoplasms but hyperplastic


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Surgery_Schwartz. be follicular carcinomas. The term suspicious for a follicular neoplasm is preferred by some laboratories for this category because up to 35% of cases turn out not to be neoplasms but hyperplastic proliferations of follicular cells, most commonly those of multinodular goiter. Lobectomy is the preferred treatment for this result, and approx-imately 15% to 35% of lesions placed in this category prove to be malignant. Hürthle cell neoplasms are also included in this category. Most papillary and other carcinomas can be diagnosed by FNA, but the features are subtle at times, such as in follicular variant of papillary carcinomas. If the diagnosis is uncertain, the lesions are classified as “suspicious for malignancy.” Lobec-tomy or near-total thyroidectomy is recommended because 60% to 75% turn out to be malignant. This category also includes lesions suspicious for medullary carcinoma and lymphoma, and ancillary testing such as immunohistochemical analysis and flow cytometry may be helpful.


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Surgery_Schwartz. out to be malignant. This category also includes lesions suspicious for medullary carcinoma and lymphoma, and ancillary testing such as immunohistochemical analysis and flow cytometry may be helpful. The risk of malignancy in lesions classified as “malignant” by FNA is 97% to 99%, and near-total/total thyroidectomy is recommended.Laboratory Studies Most patients with thyroid nodules are euthyroid. Determining the blood TSH level is helpful. If a patient with a nodule is found to be hyperthyroid, the risk of malignancy is approximately 1%. Serum Tg levels cannot dif-ferentiate benign from malignant thyroid nodules unless the lev-els are extremely high, in which case metastatic thyroid cancer should be suspected. Tg levels are, however, useful in following patients who have undergone total thyroidectomy for thyroid cancer and also for serial evaluation of patients undergoing nonoperative management of thyroid nodules. Serum calcitonin levels should be obtained in patients with MTC or a


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Surgery_Schwartz. thyroidectomy for thyroid cancer and also for serial evaluation of patients undergoing nonoperative management of thyroid nodules. Serum calcitonin levels should be obtained in patients with MTC or a family his-tory of MTC or MEN2. There is insufficient evidence to recom-mend routine calcitonin testing for all nodules. All patients with MTC should be tested for RET oncogene mutations and have a 24-hour urine collection with measurement of levels of vanil-lylmandelic acid (VMA), metanephrine, and catecholamine levels to rule out a coexisting pheochromocytoma. About 10% of patients with familial MTC and MEN2A have de novo RET mutations, so that their children are at risk for thyroid cancer.Imaging Ultrasound is helpful for detecting nonpalpable thy-roid nodules, differentiating solid from cystic nodules, and identifying adjacent lymphadenopathy. Ultrasound evaluation can identify features of a nodule that increase the a priori risk of malignancy, such as fine stippled calcification and


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Surgery_Schwartz. nodules, and identifying adjacent lymphadenopathy. Ultrasound evaluation can identify features of a nodule that increase the a priori risk of malignancy, such as fine stippled calcification and enlarged regional nodes; however, a tissue diagnosis is strongly recom-mended before thyroidectomy.20 Ultrasound also provides a noninvasive and inexpensive method of following the size of suspected benign nodules diagnosed by FNAB and for identi-fying enlarged lymph nodes. Ultrasound elastography is used to evaluate tissue stiffness noninvasively. This technique takes advantage of the fact that malignant nodules tend to be harder than benign nodules and thus deform less compared with the surrounding normal thyroid parenchyma. Larger studies are warranted before elastography and newer techniques such as contrast-enhanced ultrasound can be routinely included in the evaluation of thyroid nodules.21 CT and MRI are unnecessary in the routine evaluation of thyroid tumors except for large, fixed, or


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Surgery_Schwartz. as contrast-enhanced ultrasound can be routinely included in the evaluation of thyroid nodules.21 CT and MRI are unnecessary in the routine evaluation of thyroid tumors except for large, fixed, or substernal lesions. Scanning the thyroid with 123I or 99mTc is rarely necessary, and thyroid scanning currently is recom-mended in the assessment of thyroid nodules only in patients Solitary thyroid noduleFNABBenignMalignantNondiagnosticRepeatFNAB withu/sguidanceCystColloidnoduleAspirateReaccumulates x 3ThyroidectomyObserveContinuedgrowth,compressivesymptoms+/–FNABAUS/FLUSFN orSuspiciousfor FNSuspiciousformalignancyNear-total/ totalThyroidectomyRepeatFNABLobectomyLobectomy ornear-total/totalthyroidectomyFigure 38-14. Management of a solitary thyroid nodule based on Bethesda criteria. a = except in patients with a history of external radia-tion exposure or a family history of thyroid cancer; FNAB = fine-needle aspiration biopsy; AUS = atypia of unknown significance; FLUS = follicular lesion


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Surgery_Schwartz. in patients with a history of external radia-tion exposure or a family history of thyroid cancer; FNAB = fine-needle aspiration biopsy; AUS = atypia of unknown significance; FLUS = follicular lesion of unknown significance; FN = follicular neoplasm.Brunicardi_Ch38_p1625-p1704.indd 164401/03/19 11:20 AM 1645THYROID, PARATHYROID, AND ADRENALCHAPTER 38who have follicular thyroid nodules on FNAB and a suppressed TSH. PET scanning does not play a major role in the primary evaluation of thyroid nodules.Management. Malignant tumors are treated by thyroidectomy, as discussed earlier and later in this chapter in “Surgical Treat-ment under Malignant Thyroid Disease.” Simple thyroid cysts resolve with aspiration in about 75% of cases, although some require a second or third aspiration. If the cyst persists after three attempts at aspiration, unilateral thyroid lobectomy is rec-ommended. Lobectomy also is recommended for cysts >4 cm in diameter or complex cysts with solid and cystic


Surgery_Schwartz

Surgery_Schwartz. If the cyst persists after three attempts at aspiration, unilateral thyroid lobectomy is rec-ommended. Lobectomy also is recommended for cysts >4 cm in diameter or complex cysts with solid and cystic components, as the latter have a higher incidence of malignancy (15%). When FNAB is used in complex nodules, the solid portion should be sampled. If a colloid nodule is diagnosed by FNAB, patients should still be observed with serial ultrasound and Tg measure-ments. If the nodule enlarges, repeat FNAB often is indicated. Although controversial, levothyroxine in doses sufficient to maintain a serum TSH level between 0.1 and 1.0 μU/mL may also be administered. In areas with a high prevalence of iodine deficiency, this can decrease nodule size and potentially prevent the growth of new nodules. In iodine-sufficient populations, the data are less impressive. Randomized controlled trial analyses have shown that less than 25% of benign nodules shrink more than 50% with TSH suppression in


Surgery_Schwartz

Surgery_Schwartz. In iodine-sufficient populations, the data are less impressive. Randomized controlled trial analyses have shown that less than 25% of benign nodules shrink more than 50% with TSH suppression in iodine-replete populations. Thyroidectomy should be performed if a nodule enlarges on TSH suppression, causes compressive symptoms, or for cos-metic reasons. An exception to this general rule is the patient who has had previous irradiation of the thyroid gland or has a family history of thyroid cancer. In these patients, total or near-total thyroidectomy is recommended because of the high incidence of thyroid cancer and decreased reliability of FNAB in this setting.Malignant Thyroid DiseaseIn the United States, thyroid cancer accounts for <1% of all malignancies (2% of women and 0.5% of men) and is the most rapidly increasing cancer in women. Thyroid cancer is respon-sible for six deaths per million persons annually. Most patients present with a palpable swelling in the neck, which initiates


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Surgery_Schwartz. is the most rapidly increasing cancer in women. Thyroid cancer is respon-sible for six deaths per million persons annually. Most patients present with a palpable swelling in the neck, which initiates assessment through a combination of history, physical exami-nation, and FNAB.Molecular Genetics of Thyroid Tumorigenesis. Several oncogenes and tumor suppressor genes are involved in thy-roid tumorigenesis,22 as depicted in Table 38-5. The RET proto-oncogene (Fig. 38-15) plays a significant role in the pathogenesis of thyroid cancers. It is located on chromosome 10 and encodes a receptor tyrosine kinase, which binds sev-eral growth factors such as glial-derived neurotrophic factor and neurturin. The RET protein is expressed in tissues derived from the embryonic nervous and excretory systems. Therefore, Table 38-5Oncogenes, tumor suppressor genes, and other genetic alterations implicated in thyroid tumorigenesisGENEFUNCTIONTUMOROncogenes RETMembrane receptor with tyrosine kinase


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Surgery_Schwartz. Therefore, Table 38-5Oncogenes, tumor suppressor genes, and other genetic alterations implicated in thyroid tumorigenesisGENEFUNCTIONTUMOROncogenes RETMembrane receptor with tyrosine kinase activitySporadic and familial MTC, PTC (RET/PTC rearrangements)METSameOverexpressed in PTCTRK1SameActivated in some PTCTSH-RLinked to heterotrimeric G proteinHyperfunctioning adenomaGsα (gsp)Signal transduction molecule (GTP binding)Hyperfunctioning adenoma, follicular adenomaRasSignal transduction proteinFollicular adenoma and carcinoma, PTCPAX8/PPARγ1OncoproteinFollicular adenoma, follicular carcinomaB-Raf (BRAF)Signal transductionPTC, tall cell and poorly differentiated, anaplasticCTNNB1 (β-catenin)Signal transductionUpregulated in poorly differentiated and anaplastic cancersTERT promoterChromosome integrityMutated in thyroid cancers including PTC, FTC and anaplastic cancersTumor suppressors p53Cell cycle regulator, arrests cells in G1, induces apoptosisDedifferentiated PTC, FTC, anaplastic


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Surgery_Schwartz. integrityMutated in thyroid cancers including PTC, FTC and anaplastic cancersTumor suppressors p53Cell cycle regulator, arrests cells in G1, induces apoptosisDedifferentiated PTC, FTC, anaplastic cancersp16Cell cycle regulator, inhibits cyclin-dependent kinaseThyroid cancer cell linesPTENProtein tyrosine phosphataseFollicular adenoma and carcinomaOther genetic alterations microRNASmall, noncoding RNASpecific types upregulated in papillary and some follicular carcinomasFTC = follicular thyroid cancer; GTP = guanosine triphosphate; MTC = medullary thyroid cancer; PTC = papillary thyroid cancer.Brunicardi_Ch38_p1625-p1704.indd 164501/03/19 11:20 AM 1646SPECIFIC CONSIDERATIONSPART IIReceptorGDNFTyrosinekinaseIntracellularExtracellularSubstrateATP620618811609634830804768= MEN2A & FMTC mutation= MEN2B mutation= FMTC mutation= Hirschsprung's disease mutation918Figure 38-15. Structure of the RET tyrosine kinase receptor. Multiple endocrine neoplasia type 2A (MEN2A) and type 2B


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Surgery_Schwartz. mutation= MEN2B mutation= FMTC mutation= Hirschsprung's disease mutation918Figure 38-15. Structure of the RET tyrosine kinase receptor. Multiple endocrine neoplasia type 2A (MEN2A) and type 2B (MEN2B), famil-ial medullary thyroid cancer (FMTC), and Hirschsprung’s disease result from germline mutations in the RET proto-oncogene. The extracel-lular domain binds the ligand glial-derived neurotrophic factor (GDNF) and contains 28 cysteine residues. Mutations in cysteine residues at codons 609, 611, 618, 620, and 634, which are in the juxtamembrane region of the receptor, are associated with MEN2A and FMTC. The ATP-binding site is located intracellularly near the site, which binds the substrate for the tyrosine kinase catalytic domain. Mutations at codon 918 (Met to Thr) alter the substrate binding pocket located in the intracellular region and cause MEN2B. FMTC is associated with mutations at codons 768 and 804. ATP = adenosine triphosphate. (Reproduced with permission from Wells S,


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Surgery_Schwartz. binding pocket located in the intracellular region and cause MEN2B. FMTC is associated with mutations at codons 768 and 804. ATP = adenosine triphosphate. (Reproduced with permission from Wells S, Franz C. Medullary carcinoma of the thyroid gland, World J Surg. 2000 Aug;24(8):952-956.)RET disruption can lead to developmental abnormalities in organs derived from these systems, such as the enteric nervous system (Hirschsprung’s disease) and kidney. Germline muta-tions in the RET proto-oncogene are known to predispose to MEN2A, MEN2B, and familial MTCs, and somatic mutations have been demonstrated in tumors derived from the neural crest, such as MTCs (30%) and pheochromocytomas. The tyrosine kinase domain of RET can fuse with other genes by rearrange-ment. These fusion products also function as oncogenes and have been implicated in the pathogenesis of PTCs. At least 15 RET/PTC rearrangements have been described and appear to be early events in tumorigenesis. Young age and radiation


Surgery_Schwartz

Surgery_Schwartz. as oncogenes and have been implicated in the pathogenesis of PTCs. At least 15 RET/PTC rearrangements have been described and appear to be early events in tumorigenesis. Young age and radiation expo-sure seem to be independent risk factors for the development of RET/PTC rearrangements. Up to 70% of papillary cancers in children exposed to the radiation fallout from the 1986 Cher-nobyl disaster carry RET/PTC rearrangements, the most com-mon being RET/PTC1 and RET/PTC3. These rearrangements confer constitutive activation of the receptor tyrosine kinases. RET/PTC3 is associated with a solid type of PTC that appears to present at a higher stage and to be more aggressive. It has now been established that RET/PTC signaling involves the mitogen-activated protein kinase (MAPK) pathway via other signaling molecules such as Ras, Raf, and MEK. In normal cells, physi-ologic activation of Raf kinases occurs via direct interaction with guanosine triphosphate (GTP)–bound Ras, a membrane-bound small


Surgery_Schwartz

Surgery_Schwartz. molecules such as Ras, Raf, and MEK. In normal cells, physi-ologic activation of Raf kinases occurs via direct interaction with guanosine triphosphate (GTP)–bound Ras, a membrane-bound small G protein. Activated Raf, a serine-threonine kinase, in turn phosphorylates MEK, another serine-threonine kinase. This leads to phosphorylation of ERK/MAPK, which phosphor-ylates regulatory molecules in the nucleus, thereby altering gene expression. Aberrant activation of the MAPK pathway leads to tumorigenesis. Aside from RET/PTC alterations, mutations in the Ras genes can also activate the MAPK pathway. Mutated RAS oncogenes have been identified in up to 20% to 40% of thyroid follicular adenomas and carcinomas, multinodular goi-ters, and papillary and anaplastic carcinomas. There are three Raf kinases, A-Raf, B-Raf (BRAF), and C-Raf. Mutations in BRAF also have been implicated in aberrant MAPK pathway activation and tumorigenesis. Of the various identified BRAF mutations, T1799A (V600E amino


Surgery_Schwartz

Surgery_Schwartz. A-Raf, B-Raf (BRAF), and C-Raf. Mutations in BRAF also have been implicated in aberrant MAPK pathway activation and tumorigenesis. Of the various identified BRAF mutations, T1799A (V600E amino acid substitution) is the most common and occurs frequently in thyroid cancers. Interestingly, BRAF mutations occur in papillary and anaplastic tumors (aver-age prevalence of 44% and 22%, respectively),23 but not in fol-licular thyroid cancers, suggesting a role in the pathogenesis of these malignancies. Studies also show that BRAF mutations are associated with more aggressive clinicopathologic features, including larger tumor size, invasion, and lymphadenopathy, and may have a role as prognostic markers.The p53 gene is a tumor suppressor gene encoding a transcriptional regulator, which causes cell cycle arrest allow-ing repair of damaged DNA, thus helping to maintain genomic integrity. Mutations of p53 are rare in PTCs but common in undifferentiated thyroid cancers and thyroid cancer cell


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Surgery_Schwartz. cell cycle arrest allow-ing repair of damaged DNA, thus helping to maintain genomic integrity. Mutations of p53 are rare in PTCs but common in undifferentiated thyroid cancers and thyroid cancer cell lines. Other cell cycle regulators and tumor suppressors such as p15 and p16 are mutated more commonly in thyroid cancer cell lines than in primary tumors. An oncogene resulting from the fusion of the DNA binding domain of the thyroid-transcription fac-tor PAX8 gene to the peroxisome proliferator-activated receptor gamma 1 (PPARγ1) has been noted to play an important role Brunicardi_Ch38_p1625-p1704.indd 164601/03/19 11:21 AM 1647THYROID, PARATHYROID, AND ADRENALCHAPTER 38in the development of follicular neoplasms, including follicular cancers. Mutations in the telomerase reverse transcriptase cata-lytic subunit (TERT) promoter unit have also been recently been identified in well-differentiated thyroid cancers and appear to be related to poor prognosis. Thyroid cancer stem cells have


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Surgery_Schwartz. cata-lytic subunit (TERT) promoter unit have also been recently been identified in well-differentiated thyroid cancers and appear to be related to poor prognosis. Thyroid cancer stem cells have also been identified; however, their role in thyroid carcinogenesis remains to be determined.24 Mutations in the kinases PIK3CA and AKT1 are rare in thyroid cancers and tend to occur as late events in tumorigenesis.Specific Tumor Types Papillary Carcinoma Papillary carcinoma accounts for 80% of all thyroid malignancies in iodine-sufficient areas and is the predominant thyroid cancer in children and individuals exposed to external radiation. Papillary carcinoma occurs more often in women, with a 2:1 female-to-male ratio, and the mean age at presentation is 30 to 40 years. Most patients are euthyroid and present with a slow-growing painless mass in the neck. Dys-phagia, dyspnea, and dysphonia usually are associated with locally advanced invasive disease. Lymph node metastases are common,


Surgery_Schwartz

Surgery_Schwartz. and present with a slow-growing painless mass in the neck. Dys-phagia, dyspnea, and dysphonia usually are associated with locally advanced invasive disease. Lymph node metastases are common, especially in children and young adults, and may be the presenting complaint. “Lateral aberrant thyroid” almost always denotes a cervical lymph node that has been invaded by metastatic cancer. Suspicion of thyroid cancer often originates through physical examination of patients and a review of their history. Diagnosis is established by FNAB of the thyroid mass or lymph node. Once thyroid cancer is diagnosed on FNAB, a complete neck ultrasound is strongly recommended to evalu-ate the contralateral lobe and for lymph node metastases in the central and lateral neck compartments. Distant metastases are uncommon at initial presentation, but may ultimately develop in up to 20% of patients. The most common sites are lungs, fol-lowed by bone, liver, and brain.Pathology. On gross examination, PTCs


Surgery_Schwartz

Surgery_Schwartz. are uncommon at initial presentation, but may ultimately develop in up to 20% of patients. The most common sites are lungs, fol-lowed by bone, liver, and brain.Pathology. On gross examination, PTCs generally are hard and whitish and remain flat on sectioning with a blade, in contrast to normal tissue or benign nodular lesions that tend to bulge. Mac-roscopic calcification, necrosis, or cystic change may be appar-ent. Histologically, papillary carcinomas may exhibit papillary projections (Fig. 38-16A), a mixed pattern of papillary and fol-licular structures, or a pure follicular pattern (follicular variant). The diagnosis is established by characteristic nuclear cellular features. Cells are cuboidal with pale, abundant cytoplasm, crowded nuclei that may demonstrate “grooving,” and intranu-clear cytoplasmic inclusions (leading to the designation of Orphan Annie nuclei [Fig. 38-16B]), which allow diagnosis by FNAB. Psammoma bodies, which are microscopic, calcified deposits representing


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Surgery_Schwartz. cytoplasmic inclusions (leading to the designation of Orphan Annie nuclei [Fig. 38-16B]), which allow diagnosis by FNAB. Psammoma bodies, which are microscopic, calcified deposits representing clumps of sloughed cells, also may be present. Mixed papillary-follicular tumors and follicular variant of papillary thyroid carcinoma (FVPTC) are classified as papil-lary carcinomas because they behave biologically as papillary carcinomas. Two main subtypes of FVPTC are recognized: encapsulated and nonencapsulated (infiltrative). The for-mer is challenging to diagnose. Since the tumors have no invasion, the diagnosis relies on the finding of characteristic nuclei, which can be subjective. In addition, several studies have shown that the encapsulated tumors have an indolent behavior and are genetically distinct from their infiltrative counterparts. As such, these tumors are now designated noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP).25 Multifocality is


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Surgery_Schwartz. distinct from their infiltrative counterparts. As such, these tumors are now designated noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP).25 Multifocality is common in papillary carcinoma and may be present in up to 85% of cases on microscopic examination. Mul-tifocality is associated with an increased risk of cervical nodal metastases, and these tumors may rarely invade adjacent struc-tures such as the trachea, esophagus, and RLNs. Other variants of papillary carcinoma include tall cell, insular, columnar, dif-fuse sclerosing, clear cell, trabecular, and poorly differentiated types. These variants account for about 1% of all papillary car-cinomas and are generally associated with a worse prognosis.Minimal or occult/microcarcinoma refers to tumors of 1 cm or less in size with no evidence of local invasiveness through the thyroid capsule or angioinvasion, and that are not associated with lymph node metastases. They are nonpalpable and usually are


Surgery_Schwartz

Surgery_Schwartz. 1 cm or less in size with no evidence of local invasiveness through the thyroid capsule or angioinvasion, and that are not associated with lymph node metastases. They are nonpalpable and usually are incidental findings at operative, histologic, or autopsy examination. Studies have demonstrated occult PTC to be present in 2% to 36% of thyroid glands removed at autopsy. These tumors are also being identified more frequently due to the widespread use of ultrasound. These occult tumors are generally associated with a better prognosis than larger tumors, but they may be more aggressive than previously appreciated. About 25% of patients with these tumors have associated occult lymph node metastases.Prognostic Indicators. In general, patients with PTC have an excellent prognosis with a >95% 10-year survival rate. Sev-eral prognostic indicators have been incorporated into various 4Figure 38-16. A. Histomicrograph of a papillary thyroid cancer (hematoxylin-eosin stain). B. Fine-needle


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Surgery_Schwartz. 10-year survival rate. Sev-eral prognostic indicators have been incorporated into various 4Figure 38-16. A. Histomicrograph of a papillary thyroid cancer (hematoxylin-eosin stain). B. Fine-needle aspiration biopsy specimen from a papillary thyroid cancer showing typical intranuclear cytoplasmic inclusions in the center of the slide.Brunicardi_Ch38_p1625-p1704.indd 164701/03/19 11:21 AM 1648SPECIFIC CONSIDERATIONSPART IIstaging systems, which enable patients to be stratified into low-risk and high-risk groups. Unfortunately, all of these classifica-tion systems rely on data that are not available preoperatively.In 1987, Hay and colleagues26 at the Mayo Clinic proposed the AGES scoring system, which incorporates Age, histologic Grade, Extrathyroidal invasion, and metastases and tumor Size to predict the risk of dying from papillary cancer. Low-risk patients are young, with well-differentiated tumors, no metas-tases, and small primary lesions, whereas high-risk patients are older,


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Surgery_Schwartz. Size to predict the risk of dying from papillary cancer. Low-risk patients are young, with well-differentiated tumors, no metas-tases, and small primary lesions, whereas high-risk patients are older, with poorly differentiated tumors, local invasion, dis-tant metastases, and large primary lesions. The MACIS scale is a postoperative system modified from the AGES scale. This scale incorporates distant Metastases, Age at presentation (<40 or >40 years old), Completeness of original surgical resection, extrathyroidal Invasion, and Size of original lesion (in centime-ters) and classifies patients into four risk groups based on their scores. Cady proposed the AMES system27 to classify differen-tiated thyroid tumors into lowand high-risk groups using Age (men <40 years old, women <50 years old), Metastases, Extra-thyroidal spread, and Size of tumors (< or >5 cm). A simplified system by DeGroot and associates28 uses four groups—class I (intrathyroidal), class II (cervical nodal metastases),


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Surgery_Schwartz. Metastases, Extra-thyroidal spread, and Size of tumors (< or >5 cm). A simplified system by DeGroot and associates28 uses four groups—class I (intrathyroidal), class II (cervical nodal metastases), class III (extrathyroidal invasion), and class IV (distant metastases)—to determine prognosis. Another classification system is the TNM system (Tumor, Nodal status, Metastases; Table 38-6), which used by most medical centers in North America and has been recently updated.29 In this new version, minimal extrathyroidal extension is no longer considered T3a disease. Thyroglobulin doubling time (using levels obtained when TSH is <0.1 mIU/L) has also been demonstrated to be an independent prognostic marker for metastatic disease and recurrence.30Several molecular and genetic markers such as tumor DNA aneuploidy, decreased cyclic adenosine monophosphate response to TSH, increased epidermal growth factor binding, presence of N-ras and gsp mutations, overexpression of c-myc, and presence of p53


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Surgery_Schwartz. DNA aneuploidy, decreased cyclic adenosine monophosphate response to TSH, increased epidermal growth factor binding, presence of N-ras and gsp mutations, overexpression of c-myc, and presence of p53 mutations also have been associated with a worse prognosis. The presence of BRAF V600E mutation, as previously mentioned, is associated with aggressive tumor characteristics, including extrathyroidal extension, older age at presentation, and lymph node and distant metastases. This muta-tion also appears to be an independent predictor of both tumor recurrence (even for early-stage disease) and tumor-related mortality. Some studies propose that BRAF mutation status on FNAB can be used to tailor initial management including more extensive initial surgical excision, high-dose postoperative RAI therapy, increased TSH suppression, and closer follow-up.31 The correlation of RET/PTC rearrangements and Ras mutations with prognosis is less clear. TERT promoter mutations have been associated with


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Surgery_Schwartz. therapy, increased TSH suppression, and closer follow-up.31 The correlation of RET/PTC rearrangements and Ras mutations with prognosis is less clear. TERT promoter mutations have been associated with poor disease-specific and disease-free survival.Surgical Treatment. Most authors agree that patients with high-risk tumors (judged by any of the classification systems discussed earlier in “Prognostic Indicators”) or bilateral tumors should undergo total or near-total thyroidectomy. The optimal surgical strategy in the majority of patients with low-risk (small, unilateral) cancers was controversial for many years, with the focus of the debate centering around outcome data and risks associated with extent of thyroidectomy in this group of patients. Proponents of total thyroidectomy indicate that it enables the use of RAI to effectively detect and treat residual thyroid tissue or metastatic disease and makes serum Tg level a more sensitive marker of recurrent or persistent disease. It is


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Surgery_Schwartz. that it enables the use of RAI to effectively detect and treat residual thyroid tissue or metastatic disease and makes serum Tg level a more sensitive marker of recurrent or persistent disease. It is also known that a significant proportion (33% to 50%) of patients who develop a recurrence die from their disease,32 and even though the data are retrospective, long-term, follow-up studies suggest that recur-rence rates are lowered and that survival is improved in patients undergoing near-total or total thyroidectomy28,32-36 (Fig. 38-17). In addition, diminished survival is noted in patients with low-risk disease (mortality rates of 5% at 10 to 20 years), and it is not possible to accurately risk stratify patients preoperatively. In the last 10 years, a large study of >50,000 patients with papillary cancer demonstrated that, in multivariate analyses, total thyroid-ectomy led to a significantly improved recurrence and survival for tumors >1 cm. Furthermore, the authors also showed that


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Surgery_Schwartz. papillary cancer demonstrated that, in multivariate analyses, total thyroid-ectomy led to a significantly improved recurrence and survival for tumors >1 cm. Furthermore, the authors also showed that patients with tumors 1 to 2 cm in diameter who were treated with lobectomy had a 24% higher risk of recurrence and a 49% higher risk of thyroid cancer mortality.37 Based on this informa-tion, the American Thyroid Association 2009 guidelines for the evidence-based management of thyroid cancers recommended a near-total or total thyroidectomy for primary cancers >1 cm unless there are contraindications to the surgery.38 However, additional studies since then have demonstrated no survival dif-ferences based on initial surgical procedure when adjusting for complexity/risk and comorbid diseases.39 This finding, coupled with a trend for increased use of ultrasound and Tg measure-ments to assess for recurrences and the declining use of RAI ablation, led to revised guidelines in 2015. Accordingly,


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Surgery_Schwartz. finding, coupled with a trend for increased use of ultrasound and Tg measure-ments to assess for recurrences and the declining use of RAI ablation, led to revised guidelines in 2015. Accordingly, either near-total/total thyroidectomy or lobectomy constitute appropriate initial treatment for tumors >1 cm and <4 cm without extrathyroidal extension or lymph node involvement (cN0). Of note, the guidelines do state that the treatment team may elect near-total/total thyroidectomy to facilitate RAI ther-apy, enhance follow-up based on disease features, or if the patient expresses a preference for complete thyroid excision.40There has also been in change in the management of pap-illary microcarcinomas (<1 cm) since at least two trials from Japan have shown that active surveillance (defined as observa-tion without immediate surgery) can be a viable and safe first line of treatment for these very-low-risk tumors without extra-thyroidal extension or lymph node metastases.41 Tumors that progress


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Surgery_Schwartz. without immediate surgery) can be a viable and safe first line of treatment for these very-low-risk tumors without extra-thyroidal extension or lymph node metastases.41 Tumors that progress during monitoring are treated by surgery. If surgery is chosen as initial treatment for these patients, a thyroid lobec-tomy is considered sufficient.When PTC is diagnosed by FNAB, the definitive operation can be done without confirming the diagnosis by frozen section during the operation. Patients with a nodule that is suspicious for papillary cancer should be treated by thyroid lobectomy, isthmu-sectomy, and removal of any pyramidal lobe or adjacent lymph nodes. If intraoperative frozen-section examination of a lymph node or primary tumor confirms carcinoma, completion total or near-total thyroidectomy is performed. If a definitive diagnosis cannot be made or the surgeon is concerned about the viability of the parathyroid glands or the status of the RLN, the opera-tion is terminated. When final


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Surgery_Schwartz. is performed. If a definitive diagnosis cannot be made or the surgeon is concerned about the viability of the parathyroid glands or the status of the RLN, the opera-tion is terminated. When final histology confirms carcinoma, completion thyroidectomy is performed if deemed necessary based on risk-stratification. During thyroidectomy, enlarged or obviously involved central neck nodes should be removed (ther-apeutic central-compartment, level VI), along with nodes with known lateral neck metastases. Some investigators recommend routine bilateral central neck dissection due to the high inci-dence of microscopic metastases and data showing improved rates of recurrence and survival (compared to historic controls). 5Brunicardi_Ch38_p1625-p1704.indd 164801/03/19 11:21 AM 1649THYROID, PARATHYROID, AND ADRENALCHAPTER 38Table 38-6TNM classification of thyroid tumors PAPILLAEY or FOLLICULAR TUMORSDIAGNOSIS AGETUMORNODEMETASTASISSTAGE<55 yearsAny TAny NM0I<55 yearsAny TAny NM1II≥55


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Surgery_Schwartz. PARATHYROID, AND ADRENALCHAPTER 38Table 38-6TNM classification of thyroid tumors PAPILLAEY or FOLLICULAR TUMORSDIAGNOSIS AGETUMORNODEMETASTASISSTAGE<55 yearsAny TAny NM0I<55 yearsAny TAny NM1II≥55 yearsT1N0/NXM0I≥55 yearsT1N1M0II≥55 yearsT2N0/NXM0I≥55 yearsT2N1M0II≥55 yearsT3a/T3bAny NM0II≥55 yearsT4aAny NM0III≥55 yearsT4bAny NM0IVA≥55 yearsAny TAny NM1IVBMEDULLARY THYROID CANCERTUMORNODEMETASTASISSTAGET1N0M0IT2N0M0IIT3N0M0IIT1–3N1aM0IIIT4aAny NM0IVAT1–3N1bM0IVAT4bAny NM0IVBAny TAny NM1IVCANAPLASTIC CANCERTUMORNODEMETASTASISSTAGET1–T3aN0/NXM0IVAT1–T3aN1M0IVBT3bAny NM0IVBT4Any NM0IVBAny TAny NM1IVCDEFINITIONSPrimary tumor (T)TX = Primary tumor cannot be assessedT0 = No evidence of primary tumorT1 = Tumor ≤2 cm in greatest dimension limited to the thyroid T1a = Tumor ≤1 cm in greatest dimension limited to the thyroid T1b = Tumor >1 cm but ≤2 cm in greatest dimension limited to the thyroidT2 = Tumor >2 cm but ≤4 cm in greatest dimension limited to the thyroidT3 = Tumor >4 cm limited to


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Surgery_Schwartz. limited to the thyroid T1b = Tumor >1 cm but ≤2 cm in greatest dimension limited to the thyroidT2 = Tumor >2 cm but ≤4 cm in greatest dimension limited to the thyroidT3 = Tumor >4 cm limited to the thyroid, or gross extrathyroidal extension invading only strap muscles T3a = Tumor >4 cm limited to the thyroid T3b = Gross extrathyroidal extension invading only strap muscles (sternohyoid, sternothyroid, thyrohyoid, or omohyoid muscles) from a tumor of any sizeT4 = Includes gross extrathyroidal extension beyond the strap muscles T4a = Gross extrathyroidal extension invading subcutaneous soft tissues, larynx, trachea, esophagus, or recurrent laryngeal nerve from a tumor of any size T4b = Gross extrathyroidal extension invading prevertebral fascia or encasing the carotid artery or mediastinal vessels from a tumor of any sizeRegional lymph nodes (N)NX = Regional lymph nodes cannot be assessedN0 = No evidence of locoregional lymph node metastasis N0a = One or more cytologically or


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Surgery_Schwartz. vessels from a tumor of any sizeRegional lymph nodes (N)NX = Regional lymph nodes cannot be assessedN0 = No evidence of locoregional lymph node metastasis N0a = One or more cytologically or histologically confirmed benign lymph nodes N0b = No radiologic or clinical evidence of locoregional lymph node metastasisN1 = Metastasis to regional nodes N1a = Metastasis to level VI or VII (pretracheal, paratracheal, or prelaryngeal/Delphian, or upper mediastinal) lymph nodes. This can be unilateral or bilateral disease. N1b = Metastasis to unilateral, bilateral, or contralateral lateral neck lymph nodes (levels I, II, III, IV, or V) or retropharyngeal lymph nodesDistant Metastasis (M)M0 = No distant metastasisM1 = Distant metastasisUsed with the permission of the American College of Surgeons. Amin MB, Edge SB, Greene FL, et al. (Eds.) AJCC Cancer Staging Manual, 8th Ed. Springer New York, 2017.Brunicardi_Ch38_p1625-p1704.indd 164901/03/19 11:21 AM 1650SPECIFIC CONSIDERATIONSPART IIHowever,


Surgery_Schwartz

Surgery_Schwartz. MB, Edge SB, Greene FL, et al. (Eds.) AJCC Cancer Staging Manual, 8th Ed. Springer New York, 2017.Brunicardi_Ch38_p1625-p1704.indd 164901/03/19 11:21 AM 1650SPECIFIC CONSIDERATIONSPART IIHowever, these risks need to be balanced with the increased risk of hypoparathyroidism with routine central neck dissection and the fact that some studies do not show any difference in recur-rence rates or rates of low or undetectable Tg levels. The updated 2015 ATA guidelines for thyroid cancer management suggest that prophylactic (ipsilateral or bilateral) dissection may be per-formed in patients with advanced (T3 or T4) papillary thyroid carcinoma, or if the lateral neck nodes are involved with tumor (N1b), or if the information will help in treatment planning.40 The American Head and Neck Society urges the involvement of multidisciplinary teams in the decision-making process for pro-phylactic CND and indicates that it can be considered in patients with high risk of recurrence (to include older


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Surgery_Schwartz. the involvement of multidisciplinary teams in the decision-making process for pro-phylactic CND and indicates that it can be considered in patients with high risk of recurrence (to include older or young age, mul-tifocal disease and extrathyroidal extension in addition to the aforementioned factors).42 Further prospective studies are needed before definitive recommendations can be made in this regard.Biopsy-proven lymph node metastases detected clini-cally or by imaging in the lateral neck in patients with papil-lary carcinoma are managed with modified radical or functional neck dissection,40 as described later in this chapter in “Thyroid Surgery.” Dissection of the posterior triangle and suprahyoid dissection usually are not necessary unless there is extensive metastatic disease in levels 2, 3, and 4, but should be performed when appropriate. Prophylactic lateral neck node dissection is not necessary in patients with PTC because these cancers do not appear to metastasize systemically


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Surgery_Schwartz. 2, 3, and 4, but should be performed when appropriate. Prophylactic lateral neck node dissection is not necessary in patients with PTC because these cancers do not appear to metastasize systemically from lymph nodes, and micrometastases often can be ablated with RAI therapy.Follicular Carcinoma Follicular carcinomas account for 10% of thyroid cancers and occur more commonly in iodinedeficient areas. The overall incidence of this tumor is declining in the United States, probably due to iodine supplementation and improved histologic classification. Women have a higher incidence of follicular cancer, with a female-to-male ratio of 3:1, and a mean age at presentation of 50 years old. Follicular cancers usually present as solitary thyroid nodules, occasion-ally with a history of rapid size increase, and long-standing goi-ter. Pain is uncommon, unless hemorrhage into the nodule has occurred. Unlike papillary cancers, cervical lymphadenopathy is uncommon at initial presentation (about 5%),


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Surgery_Schwartz. and long-standing goi-ter. Pain is uncommon, unless hemorrhage into the nodule has occurred. Unlike papillary cancers, cervical lymphadenopathy is uncommon at initial presentation (about 5%), although distant metastases may be present. In <1% of cases, follicular cancers may be hyperfunctioning, leading patients to present with signs and symptoms of thyrotoxicosis. FNAB is unable to distinguish benign follicular lesions from follicular carcinomas. Therefore, preoperative clinical diagnosis of cancer is difficult unless dis-tant metastases are present. Large follicular tumors (>4 cm) in older men are more likely to be malignant.Due to the limitations inherent in the FNAB diagnosis, a number of studies have focused on identifying molecular mark-ers to distinguish benign from malignant follicular lesions. Many of these genetic changes can be identified using tissue obtained during FNAB. While no single marker has met the ideal charac-teristics of being simple to use, reproducible, and


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Surgery_Schwartz. lesions. Many of these genetic changes can be identified using tissue obtained during FNAB. While no single marker has met the ideal charac-teristics of being simple to use, reproducible, and cost-effective, several combinations of markers appear to be useful in differen-tiating benign from malignant lesions. A commonly used panel of seven genes used to “rule in” malignancy detects mutations in BRAF, Ras, RET/PTC, and PAX/PPARg and has been associated with a sensitivity of 57% to 75%, specificity of 97% to 100%, PPV of 87% to 100%, and NPV of 79% to 86% in the case of nodules consistent with Follicular/Hürthle cell neoplasm or sus-picious of the same.43 In contrast, the Afirma Gene Expression Classifier (GEC) uses a “rule out” strategy to identify benign nodules. This method uses material from additional FNA passes (in an RNA-preserving solution) to analyze a 167 gene panel, and the results obtained are reported as benign or suspicious.44 It is reported to have a lower PPV of 37% but


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Surgery_Schwartz. from additional FNA passes (in an RNA-preserving solution) to analyze a 167 gene panel, and the results obtained are reported as benign or suspicious.44 It is reported to have a lower PPV of 37% but a better NPV of 94% for Follicular/Hürthle cell neoplasms. Next generation sequenc-ing techniques have been used to enhance malignancy detection Less than near-totalthyroidectomyP = 0.02Less thannear-totalthyroidectomy00510152025303524681012Cumulative death (%)Near-total or totalthyroidectomyNear-totalor totalthyroidectomyYears after initial therapy04361135262907227218111200640290698555464416365131432092100032Figure 38-17. Improved survival in patients with papillary or follicular thyroid cancer following total or near-total thyroidectomy compared to those who underwent less than near-total thyroidectomy. (Reproduced with permission from Mazzaferri E, Jhiang S: Long-term impact of initial surgical and medical therapy on papillary and follicular thyroid cancer, Am J Med. 1994


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Surgery_Schwartz. near-total thyroidectomy. (Reproduced with permission from Mazzaferri E, Jhiang S: Long-term impact of initial surgical and medical therapy on papillary and follicular thyroid cancer, Am J Med. 1994 Nov;97(5):418-428.)Brunicardi_Ch38_p1625-p1704.indd 165001/03/19 11:21 AM 1651THYROID, PARATHYROID, AND ADRENALCHAPTER 38by including additional mutations and gene arrangements. The advanced version of this assay (ThyroSeqV2) had a sensitivity of 90%, specificity of 93%, PPV of 83%, and NPV of 96% in a study of Follicular/Hüurthle cell neoplasm/suspicious of the same nodules, making it useful as both a “rule in” and “rule out” test.45 Of note, these assays have also been evaluated in “AUS/FLUS” and “suspicious for malignancy” nodules with varying results, i.e., the performance characteristics of these tests have been noted to change depending upon the prevalence of malig-nancy in the tested population (pretest probability). At this time, the ATA guidelines do not advise molecular


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Surgery_Schwartz. of these tests have been noted to change depending upon the prevalence of malig-nancy in the tested population (pretest probability). At this time, the ATA guidelines do not advise molecular testing in the work-up of “suspicious for malignancy” nodules. Molecular testing may be used to supplement cytology results for malignancy risk assessment in “AUS/FLUS” or “follicular/Hürthle cell neo-plasm/suspicious of the same” nodules depending on feasibility and informed patient preference.40 Expression arrays also have been used to investigate the role of microRNAs, which are a new class of small, noncoding RNAs that have been implicated in carcinogenesis. The specific microRNAs miR-197 and miR-346 are upregulated in follicular thyroid cancers46 and have the potential to be used as diagnostic markers. Additional studies have also demonstrated the feasibility of studying a panel of microRNAs in a small number of FNA samples. ThyGenX/ThyraMIR uses a mutation panel supplemented with 10 miRNA


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Surgery_Schwartz. markers. Additional studies have also demonstrated the feasibility of studying a panel of microRNAs in a small number of FNA samples. ThyGenX/ThyraMIR uses a mutation panel supplemented with 10 miRNA markers,47 whereas Rosetta GX Reveal is exclusively based on miRNA markers; however, both require further validation.48Pathology. Follicular carcinomas usually are solitary lesions, and the majority are surrounded by a capsule. Histologically, follicles are present, but the lumen may be devoid of colloid. Architectural patterns depend on the degree of differentiation demonstrated by the tumor. Malignancy is defined by the pres-ence of capsular and vascular invasion (Fig. 38-18). In general, minimally invasive tumors appear grossly encapsulated and have microscopic invasion through the tumor capsule without extension into the parenchyma and/or invasion into smallto medium-sized vessels (venous caliber) in or immediately out-side the capsule, but not within the tumor. On the other hand,


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Surgery_Schwartz. capsule without extension into the parenchyma and/or invasion into smallto medium-sized vessels (venous caliber) in or immediately out-side the capsule, but not within the tumor. On the other hand, widely invasive tumors demonstrate evidence of large vessel invasion and/or broad areas of tumor invasion through the cap-sule. They may, in fact, be unencapsulated. It is important to note that there is a wide variation of opinion among clinicians and pathologists with respect to the above definitions. Tumor infiltration and invasion, as well as tumor thrombus within the middle thyroid or jugular veins, may be apparent at operation.Surgical Treatment and Prognosis. Patients diagnosed by FNAB as having a follicular lesion should undergo thyroid lobectomy because at least 70% to 80% of these patients will have benign adenomas. Total thyroidectomy is recommended by some surgeons in older patients with follicular lesions >4 cm because of the higher risk of cancer in this setting (50%) and


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Surgery_Schwartz. patients will have benign adenomas. Total thyroidectomy is recommended by some surgeons in older patients with follicular lesions >4 cm because of the higher risk of cancer in this setting (50%) and certainly should be performed in patients with atypia on FNA, a family history of thyroid cancer, or a history of radiation exposure. Intraoperative frozen-section examination usually is not helpful, but it should be performed when there is evidence of capsular or vascular invasion or when adjacent lymphadenopa-thy is present. Total thyroidectomy should be performed when thyroid cancer is diagnosed. There is debate among experts about whether patients with minimally invasive follicular can-cers should undergo completion thyroidectomy because the prognosis is so good in these patients. A diagnosis of frankly invasive carcinoma or follicular carcinoma with angioinvasion, with or without capsular invasion, necessitates completion of total thyroidectomy primarily so that 131I can be used to


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Surgery_Schwartz. of frankly invasive carcinoma or follicular carcinoma with angioinvasion, with or without capsular invasion, necessitates completion of total thyroidectomy primarily so that 131I can be used to detect and ablate metastatic disease. Prophylactic nodal dissection is not needed because nodal involvement is infrequent, but in the unusual patient with nodal metastases, therapeutic neck dissec-tion is recommended. Prophylactic central neck dissection may be considered in patients with large tumors. The cumulative mortality from follicular thyroid cancer is approximately 15% at 10 years and 30% at 20 years. Poor long-term prognosis is predicted by age over 50 years old at presentation, tumor size >4 cm, higher tumor grade, marked vascular invasion, extrathy-roidal invasion, and distant metastases at the time of diagnosis.Hürthle Cell Carcinoma Hürthle cell carcinomas account for approximately 3% of all thyroid malignancies and, under the World Health Organization classification, are


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Surgery_Schwartz. at the time of diagnosis.Hürthle Cell Carcinoma Hürthle cell carcinomas account for approximately 3% of all thyroid malignancies and, under the World Health Organization classification, are considered to be a subtype of follicular thyroid cancer. Hürthle cell cancers also are characterized by vascular or capsular invasion and, there-fore, cannot be diagnosed by FNAB. Tumors contain sheets of eosinophilic cells packed with mitochondria, which are derived from the oxyphilic cells of the thyroid gland. Hürthle cell tumors differ from follicular carcinomas in that they are more often multifocal and bilateral (about 30%), usually do not take up RAI (about 5%), are more likely to metastasize to local nodes (25%) and distant sites, and are associated with a higher mortal-ity rate (about 20% at 10 years). Hence, they are considered to be a separate class of tumors by some groups.Management is similar to that of follicular neoplasms, with lobectomy and isthmusectomy being sufficient surgical


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Surgery_Schwartz. 10 years). Hence, they are considered to be a separate class of tumors by some groups.Management is similar to that of follicular neoplasms, with lobectomy and isthmusectomy being sufficient surgical treatment for unilateral Hürthle cell adenomas. When Hürthle cell neoplasms are found to be invasive on definitive paraffin-section histology, then total thyroidectomy should be performed. These patients should also undergo routine central neck node removal, similar to patients with MTC, and modified radical neck dissection when lateral neck nodes are palpable or identi-fied by ultrasonography. Although RAI scanning and ablation usually are ineffective, they probably should be considered to ablate any residual normal thyroid tissue and occasionally ablate tumors because there is no other good therapy.Postoperative Management of Differentiated Thyroid Cancer Radioiodine Therapy The issue of whether RAI therapy offers any benefit to patients with differentiated thyroid cancer Figure


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Surgery_Schwartz. good therapy.Postoperative Management of Differentiated Thyroid Cancer Radioiodine Therapy The issue of whether RAI therapy offers any benefit to patients with differentiated thyroid cancer Figure 38-18. Hematoxylin-eosin–stained section from follicular thyroid carcinoma showing capsular invasion.Brunicardi_Ch38_p1625-p1704.indd 165101/03/19 11:21 AM 1652SPECIFIC CONSIDERATIONSPART IIremains controversial in the absence of prospective, random-ized controlled trials. Long-term cohort studies by Mazzaferri and associates and DeGroot and colleagues demonstrate that postoperative RAI therapy reduces recurrence (Fig. 38-19) and provides a small improvement in survival, even in low-risk patients.28,34 Screening with RAI is more sensitive than chest X-ray or CT scanning for detecting metastases; however, it is less sensitive than Tg measurements for detecting metastatic disease in most differentiated thyroid cancers except Hürthle cell tumors. Screening and treatment are facilitated by


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Surgery_Schwartz. however, it is less sensitive than Tg measurements for detecting metastatic disease in most differentiated thyroid cancers except Hürthle cell tumors. Screening and treatment are facilitated by the removal of all normal thyroid tissue, which effectively competes for iodine uptake. Metastatic differentiated thyroid carcinoma can be detected and treated by 131I in about 75% of patients. Multiple studies show that RAI effectively treats >70% of lung micrometastases that are detected by RAI scan in the presence of a normal chest X-ray, whereas the success rates drop to <10% with pulmonary macrometastases. Early detection therefore is very important to improve prognosis.Several features place patients at increased risk for local recurrences or metastases. The 2015 ATA guidelines use various features to risk-stratify tumors.40 Low-risk papillary thyroid cancer includes those without local tumor invasion, all macroscopic tumor resected, absence of aggressive histol-ogy (e.g., tall cell,


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Surgery_Schwartz. features to risk-stratify tumors.40 Low-risk papillary thyroid cancer includes those without local tumor invasion, all macroscopic tumor resected, absence of aggressive histol-ogy (e.g., tall cell, columnar cell carcinoma), no known dis-tant metastases (clinical or on RAI scan if done), no vascular invasion, clinical N0 or ≤5 pathologic N1 micrometastases (<0.2 cm in largest dimension), intrathyroidal, encapsulated fol-licular variant of papillary thyroid cancer, intrathyroidal, well differentiated follicular thyroid cancer with capsular invasion and no or minimal (<4 foci) vascular invasion and intrathyroi-dal papillary microcarcinoma (unifocal or multifocal, including BRAFV600E mutated). Intermediate-risk tumors include those showing microscopic invasion of tumor into the perithyroidal soft tissues or RAI-avid metastatic foci in the neck on the first posttreatment whole-body RAI scan. This group also includes tumors with aggressive histology (e.g., tall cell, columnar cell


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Surgery_Schwartz. soft tissues or RAI-avid metastatic foci in the neck on the first posttreatment whole-body RAI scan. This group also includes tumors with aggressive histology (e.g., tall cell, columnar cell carcinoma), papillary thyroid cancer with vascular invasion, clinical N1 or >5 pathologic N1 with all involved lymph nodes <3 cm in largest dimension and multifocal papillary microcar-cinoma with extra-thyroidal extension (ETE) and BRAFV600E mutated (if known). High-risk tumors include those demon-strating macroscopic invasion of tumor into the perithyroidal soft tissues (gross ETE), incomplete tumor resection, and pres-ence of distant metastases (or postoperative serum thyroglobu-lin suggestive of distant metastase) or pathologic N1 with any metastatic lymph node ≥3 cm in largest dimension. Follicular thyroid cancers with extensive vascular invasion (>4 foci of vascular invasion) also fall into this category. It is important to note that this risk assessment represents a continuum with recurrence


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Surgery_Schwartz. thyroid cancers with extensive vascular invasion (>4 foci of vascular invasion) also fall into this category. It is important to note that this risk assessment represents a continuum with recurrence rates from 1% to 2% for low-risk cancers to >50% for high-risk cancers.The current ATA guidelines recommend RAI therapy after surgical treatment for all patients with high-risk disease, i.e., those with gross ETE and M1 disease. RAI therapy is not rec-ommended for patients with papillary microcarcinomas, either uni -or multifocal. RAI remnant ablation is not routinely recom-mended after thyroidectomy for ATA low-risk DTC patients. However, it may be considered in patients with aggressive histology or vascular invasion. Consideration of RAI is recom-mended for patients with intermediate-risk disease and “gen-erally favored” for patients with microscopic ETE due to the risk of recurrent disease, large (>2–3 cm) or clinically evident lymph nodes (central, mediastinal, and lateral neck) or


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Surgery_Schwartz. disease and “gen-erally favored” for patients with microscopic ETE due to the risk of recurrent disease, large (>2–3 cm) or clinically evident lymph nodes (central, mediastinal, and lateral neck) or presence of extranodal extension. Advancing age may also favor RAI use. However, RAI is not needed for patients with a few (<5) microscopic nodal metastases in the central compartment in the absence of other adverse features as there is insufficient evi-dence for its utility in this setting. It is generally favored for patients with lateral neck disease. There is currently no estab-lished role for molecular testing in determining RAI therapy.Remnant ablation can be performed with either thyroid hormone withdrawal or recombinant TSH (rTSH) stimula-tion. This is based on randomized studies showing that both techniques are equally effective in preparing patients for abla-tion, with the latter being associated with an improved quality of life.49,50 In patients with ATA high-risk disease


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Surgery_Schwartz. showing that both techniques are equally effective in preparing patients for abla-tion, with the latter being associated with an improved quality of life.49,50 In patients with ATA high-risk disease (including distant metastases), there is insufficient data to recommend thy-rogen-mediated ablation, and hormone withdrawal is preferred. Furthermore, if patients have comorbidities that can be exac-erbated by severe hypothyroidism (cardiac or psychiatric con-ditions), consideration should be given to thyrogen-mediated RAI. If hormone withdrawal is used, T4 therapy should be dis-continued for approximately 6 weeks before scanning with 131I. Patients should receive T3 during this time period to decrease the period of hypothyroidism. T3 has a shorter half-life than T4 (1 day vs. 1 week) and needs to be discontinued for 2 weeks to allow TSH levels to rise before treatment. Levels >30 mU/L are considered optimal, based on noncontrolled studies. A low-iodine diet also is recommended during this


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Surgery_Schwartz. to be discontinued for 2 weeks to allow TSH levels to rise before treatment. Levels >30 mU/L are considered optimal, based on noncontrolled studies. A low-iodine diet also is recommended during this 2-week period. The usual protocol involved administering a screening dose of 1 to 3 mCi and measuring uptake 24 hours later. After a total thy-roidectomy, this value should be <1%. A “hot” spot in the neck after initial screening usually represents residual normal tissue in the thyroid bed. Some investigators recommend omitting the scanning dose altogether to minimize thyrocyte “stunning” and subsequent requirement for higher treatment doses. Others recommend scanning only if the size of the remnant cannot be determined by the operative report or ultrasound, or if the results would alter the decision to treat or the dose to be administered. Current guidelines recommend using either 123I or low-activity 131I (1to 3-mCi dose) and delivering a therapeutic dose within 72 hours.The recommended


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Surgery_Schwartz. to treat or the dose to be administered. Current guidelines recommend using either 123I or low-activity 131I (1to 3-mCi dose) and delivering a therapeutic dose within 72 hours.The recommended dose of RAI is 30 mCi if remnant abla-tion is performed after total thyroidectomy for ATA low-risk thyroid or intermediate-risk cancer with lower risk features (i.e., low-volume central neck nodal metastases with no other known gross residual disease or any other adverse features). If RAI is given for adjuvant treatment to treat suspected microscopic dis-ease (in the absence of metastatic disease), doses ranging from 30 to 150 mCi are recommended, and there is no solid evidence to show that higher doses reduce the recurrence rates for T3 and N1 disease in this setting.If patients have an elevated Tg level, but negative RAI scan on follow-up, some physicians recommend treating once with 100 mCi of 131I and repeating the imaging 1 to 2 weeks later. Approximately one-third of these patients


Surgery_Schwartz

Surgery_Schwartz. Tg level, but negative RAI scan on follow-up, some physicians recommend treating once with 100 mCi of 131I and repeating the imaging 1 to 2 weeks later. Approximately one-third of these patients demonstrate uptake on posttreatment imaging, and Tg levels usually decrease in these patients, documenting therapeutic benefit. The maxi-mum dose of radioiodine that can be administered at one time without performing dosimetry is approximately 200 mCi with a cumulative dose of 1000 to 1500 mCi. Up to 500 mCi can be given with proper pretreatment dosimetry. Recent studies also Brunicardi_Ch38_p1625-p1704.indd 165201/03/19 11:21 AM 1653THYROID, PARATHYROID, AND ADRENALCHAPTER 38Initial medical therapyall recurrencesNoneT4 aloneP< .05403530252015105P< .0001Years after initial therapyPercent cancer recurrences605040302010004035302520151050NoneT4 + RAI T4 alone T4 + RAI remnant


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Surgery_Schwartz. therapyall recurrencesNoneT4 aloneP< .05403530252015105P< .0001Years after initial therapyPercent cancer recurrences605040302010004035302520151050NoneT4 + RAI T4 alone T4 + RAI remnant ablation34/16315/230101/78922/1120/13551/6035/823/10217/4621/661/847/3782/541/6710/3264/390/386/2290/250/2610/1350/130/181/51Initial medical therapydistant recurrencesNoneT4 aloneP<.0002P<.02Years after initial therapyPercent distant recurrence35302520151050None 8/163 9/112 3/82 0/66 1/54 4/39 0/25 0/13T4 alone 19/789 15/603 7/462 0/378 2/326 4/229 8/135 1/51T4 + RAI 2/230 0/135 1/102 0/84 1/67 0/38 0/26 0/11T4 + RAI remnant ablationABFigure 38-19. Tumor recurrence at a median of 16.7 years after thyroid surgery. The numerator is the number of patients with recurrence, and the denominator is the number of patients in each time interval. The P values


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Surgery_Schwartz. recurrence at a median of 16.7 years after thyroid surgery. The numerator is the number of patients with recurrence, and the denominator is the number of patients in each time interval. The P values are derived from log-rank statistical analysis of 40-year life-table data. Figure shows that all recurrences (A) and distant metastases (B) were reduced in patients who received radioactive iodine (RAI) in addition to thyroxine (T4) therapy. (Reproduced with permission from Mazzaferri E, Kloos R: Current approaches to primary therapy for papillary and follicular thyroid cancer, Clin Endocrinol Metab. 2001 Apr;86(4):1447-1363.)Brunicardi_Ch38_p1625-p1704.indd 165301/03/19 11:21 AM 1654SPECIFIC CONSIDERATIONSPART IIshow an increase in the number of second cancers in patients treated with RAI.51 The early and delayed complications of RAI therapy are listed in Table 38-7.Thyroid Hormone T4 is necessary as replacement therapy in patients after total or near-total thyroidectomy, and also has


Surgery_Schwartz

Surgery_Schwartz. The early and delayed complications of RAI therapy are listed in Table 38-7.Thyroid Hormone T4 is necessary as replacement therapy in patients after total or near-total thyroidectomy, and also has the additional effect of suppressing TSH and reducing the growth stimulus for any possible residual thyroid cancer cells. TSH suppression reduces tumor recurrence rates. Current guidelines advise maintaining initial TSH levels <0.1 mU/mL in patients with high-risk thyroid cancer and in the range of 0.1 to 0.5 mU/mL in patients with intermediate-risk disease. For low-risk patients (with or without remnant ablation) with undetectable serum Tg levels, TSH levels can be maintained at the lower end of the reference range (0.5–2 mU/L). If these patients have low measureable Tg levels, it is recommended that TSH be maintained at or slightly below lower limit of normal (0.1 to 0.5 mU/L) while continuing surveillance for recurrence. In low-risk patients treated with lobectomy alone, it is advised


Surgery_Schwartz

Surgery_Schwartz. that TSH be maintained at or slightly below lower limit of normal (0.1 to 0.5 mU/L) while continuing surveillance for recurrence. In low-risk patients treated with lobectomy alone, it is advised to keep TSH in the mid to lower reference range (0.5–2 mU/L), and hor-mone therapy may be needed to maintain these levels. Further TSH suppression levels are determined by response to therapy. The risk of tumor recurrence must be balanced with the side effects associated with prolonged TSH suppression, including osteopenia and cardiac problems, particularly in older patients.Follow-Up of Patients With Differentiated Thyroid Cancer Thyroglobulin Measurement Tg and anti-Tg antibody levels should be measured initially at 6 to 12 month intervals and more frequently in patients with high-risk tumors. Further measure-ments are guided by response to therapy. Patients are considered to have an excellent response to treatment if suppressed Tg is <0.2 ng/mL and stimulated Tg is <1 ng/mL with negative


Surgery_Schwartz

Surgery_Schwartz. Further measure-ments are guided by response to therapy. Patients are considered to have an excellent response to treatment if suppressed Tg is <0.2 ng/mL and stimulated Tg is <1 ng/mL with negative imag-ing. In these patients, Tg levels can be followed every 12 to 24 months while on thyroid hormone as their risk of recurrence is low (1–4%). Patients with structurally or biochemically incomplete (negative imaging but suppressed Tg ≥1 ng/mL or stimulated Tg ≥10 ng/mL or rising anti-Tg levels) or indeter-minate responses (nonspecific imaging findings, suppressed Tg detectable but <1 ng/mL, and stimulated Tg detectable but <10 ng/mL or stable or declining anti-Tg levels) require addi-tional investigations.40 Tg measurements in FNAB aspirates have also been shown to be useful in the detection of nodal metastatic disease.52Imaging After the first posttreatment scan, lowand some intermediate-risk patients with negative TSH-stimulated Tg and cervical ultrasound do not require routine


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Surgery_Schwartz. of nodal metastatic disease.52Imaging After the first posttreatment scan, lowand some intermediate-risk patients with negative TSH-stimulated Tg and cervical ultrasound do not require routine diagnostic whole-body radioiodine scans. However, diagnostic whole-body scans 6 to 12 months after remnant ablation may be of value in the follow-up of patients with highor intermediate-risk patients with higher risk features. Other scenarios for follow-up scans include patients with abnormal uptake outside the thyroid bed on posttherapy scan, those with poorly informative postablation scans (e.g., due to high thyroid bed uptake), and patients with Tg antibodies.Cervical ultrasound be performed to evaluate the thyroid bed and central and lateral cervical nodal compartments at 6 and 12 months after thyroidectomy and then annually for at least 3 to 5 years, depending on the patient’s risk for recurrent disease and Tg status. Sonographically suspicious nodes ≥8 to 10 mm on the smallest diameter


Surgery_Schwartz

Surgery_Schwartz. thyroidectomy and then annually for at least 3 to 5 years, depending on the patient’s risk for recurrent disease and Tg status. Sonographically suspicious nodes ≥8 to 10 mm on the smallest diameter measurement should be biopsied for cytology as well as Tg measurement in the aspirate washout. Smaller nodes can be followed and biopsied if there is contin-ued growth. FDG-PET and PET-CT scans have been shown to be useful to localize recurrent or persistent thyroid cancer in patients who have Tg-positive, RAI scan–negative disease. FDG-PET can also be useful for the initial staging of patients with poorly differentiated thyroid carcinomas or Hürthle cell tumors, particularly in patients with other evidence of disease on imaging or Tg levels. In addition, they may be used as a prog-nostic tool in patients with metastatic disease and to evaluate the response to treatment in patients with metastatic or locally advanced disease.Additional Treatment Modalities Radiotherapy, Thermal Ablation,


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Surgery_Schwartz. in patients with metastatic disease and to evaluate the response to treatment in patients with metastatic or locally advanced disease.Additional Treatment Modalities Radiotherapy, Thermal Ablation, and Chemotherapy External-beam radiotherapy is occasionally required to control unresectable, locally invasive, or recurrent disease and to treat metastases in support bones to decrease the risk of fractures. It also is of value for the treatment and control of pain from bony metastases when there is minimal or no RAIU. Stereotac-tic brain radiotherapy and intensity-modulated radiation therapy have both been used successfully for metastatic lesions. Percuta-neous thermal ablation by increasing (radiofrequency ablation) or decreasing temperature (cryoablation) in the lesion to induce irreversible cellular damage has shown promise for lung, bone, and liver lesions.53,54 Single-drug and multidrug chemotherapy has been used with little success in disseminated thyroid can-cer, and there is no


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Surgery_Schwartz. cellular damage has shown promise for lung, bone, and liver lesions.53,54 Single-drug and multidrug chemotherapy has been used with little success in disseminated thyroid can-cer, and there is no role for routine chemotherapy. Doxorubicin (Adriamycin) and paclitaxel (Taxol) were previously the most frequently used agents. The former acts as a radiation sensitizer and should be considered in patients undergoing external-beam radiation.Novel Therapies These therapies are directed at the molecular pathways known to be involved in thyroid cancers. Sorafenib Table 38-7Complications of radioactive iodine therapy (131I) and doses at which they are observedACUTELONG-TERMNeck pain, swelling, and tendernessThyroiditis (if remnant present)Sialadenitis (50–450 mCi), taste dysfunctionHemorrhage (brain metastases)Cerebral edema (brain metastases, 200 mCi)Vocal cord paralysisNausea and vomiting (50–450 mCi)Bone marrow suppression (200 mCi)HematologicBone marrow suppression (>500 mCi)Leukemia (>1000


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Surgery_Schwartz. metastases)Cerebral edema (brain metastases, 200 mCi)Vocal cord paralysisNausea and vomiting (50–450 mCi)Bone marrow suppression (200 mCi)HematologicBone marrow suppression (>500 mCi)Leukemia (>1000 mCi)FertilityOvarian/testicular damage, infertilityIncreased spontaneous abortion ratePulmonary fibrosisChronic sialadenitis, nodules, taste dysfunctionIncreased risk of cancerAnaplastic thyroid cancerGastric cancerHepatocellular cancerLung cancerBreast cancer (>1000 mCi)Bladder cancerHypoparathyroidismBrunicardi_Ch38_p1625-p1704.indd 165401/03/19 11:21 AM 1655THYROID, PARATHYROID, AND ADRENALCHAPTER 38and lenvatinib are U.S. Food and Drug Administration (FDA) and European Medical Agency (EMA)-approved for use in patients with advanced differentiated thyroid cancer that is non-responsive to RAI after evaluation in phase 3 placebo-controlled double blinded trials (the DECISION study and the SELECT study, respectively).55,56 Both drugs are multikinase inhibitors and target RET kinase


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Surgery_Schwartz. to RAI after evaluation in phase 3 placebo-controlled double blinded trials (the DECISION study and the SELECT study, respectively).55,56 Both drugs are multikinase inhibitors and target RET kinase and the vascular endothelial growth factor (VEGF)-receptor; however, lenvatinib also inhib-its the fibroblast growth factor and the platelet-derived growth factor receptor. Sorafenib demonstrated progression-free sur-vival (PFS) improvement by 5 months with about 12% partial response rates, whereas lenvatinib prolonged median PFS by 15.7 months compared with placebo with response rates of 65%, including some complete responses. Vandetanib is mainly a RET-kinase inhibitor, but it also affects the VEGF-receptor and epidermal growth factor receptor. It has been evaluated in a phase 2 trial and also demonstrated an improved PFS.57 However, none of the agents show improvements in overall survival. Moreover, they are associated with significant side effects (diarrhea, fatigue hypertension,


Surgery_Schwartz

Surgery_Schwartz. also demonstrated an improved PFS.57 However, none of the agents show improvements in overall survival. Moreover, they are associated with significant side effects (diarrhea, fatigue hypertension, hepatotoxicity, bleed-ing, and thrombosis) that affect patient quality of life. As such, they are considered only in patients with metastatic, rapidly progressive, symptomatic disease that is unable to respond to other local treatment approaches and generally in the context of clinical trials. Oncogenic kinase inhibitors that selectively inhibit the mutant V600E BRAF kinase (dabrafenib) has also shown promise in treating a subset of patients with advanced differentiated thyroid cancer.58Medullary Carcinoma MTC accounts for about 5% of thyroid malignancies and arises from the parafollicular or C cells of the thyroid, which, in turn, are derived from the ultimobranchial bod-ies. These cells are concentrated superolaterally in the thyroid lobes, and this is where MTC usually develops. C cells


Surgery_Schwartz

Surgery_Schwartz. cells of the thyroid, which, in turn, are derived from the ultimobranchial bod-ies. These cells are concentrated superolaterally in the thyroid lobes, and this is where MTC usually develops. C cells secrete calcitonin, a 32-amino-acid polypeptide that functions to lower serum calcium levels, although its effects in humans are mini-mal. Most MTCs occur sporadically. However, approximately 25% occur within the spectrum of several inherited syndromes such as familial MTC, MEN2A, and MEN2B. All these variants are known to result secondary to germline mutations in the RET proto-oncogene. The syndromes also are characterized by geno-type-phenotype correlations, with specific mutations leading to particular clinical manifestations. The salient clinical and genetic features of these syndromes are outlined in Table 38-8. Some clinical features of MEN2B patients are shown in Fig. 38-20.Table 38-8Clinical and genetic features of medullary thyroid cancer syndromesSYNDROMEMANIFESTATIONSRET


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Surgery_Schwartz. are outlined in Table 38-8. Some clinical features of MEN2B patients are shown in Fig. 38-20.Table 38-8Clinical and genetic features of medullary thyroid cancer syndromesSYNDROMEMANIFESTATIONSRET MUTATIONSMEN2A MTC, pheochromocytoma, primary hyperparathyroidism, lichen planus amyloidosis Exon 10—codons 609, 611, 618, 620Exon 11—codon 634 (more commonly associated with pheochromocytoma and primary hyperparathyroidism)MEN2BMTC, pheochromocytoma, Marfanoid habitus, mucocutaneous ganglioneuromatosisExon 16—codon 918Familial MTCMTCCodons 609, 611, 618, 620, and 634 Codons 768, 790, 791, or 804 (rare)MEN2A and Hirschsprung’s diseaseMTC, pheochromocytoma, primary hyperparathyroidism, Hirschsprung’s diseaseCodons 609, 618, 620MEN2 = multiple endocrine neoplasia type 2; MTC = medullary thyroid cancer.BAFigure 38-20. Features of MEN2B: thickened lips (A) and mucosal neuromas (A and B).Brunicardi_Ch38_p1625-p1704.indd 165501/03/19 11:21 AM 1656SPECIFIC CONSIDERATIONSPART IIPatients with MTC


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Surgery_Schwartz. 38-20. Features of MEN2B: thickened lips (A) and mucosal neuromas (A and B).Brunicardi_Ch38_p1625-p1704.indd 165501/03/19 11:21 AM 1656SPECIFIC CONSIDERATIONSPART IIPatients with MTC often present with a neck mass that may be associated with palpable cervical lymphadenopathy (15% to 20%). Pain or aching is more common in patients with these tumors, and local invasion may produce symptoms of dys-phagia, dyspnea, or dysphonia. Distant blood-borne metastases to the liver, bone (frequently osteoblastic), and lung occur later in the disease. The female-to-male ratio is 1.5:1. Most patients present between 50 and 60 years old, although patients with familial disease present at a younger age. Medullary thyroid tumors secrete not only calcitonin and carcinoembryonic anti-gen (CEA), but also other peptides such as calcitonin gene–related peptide, histaminadases, prostaglandins E2 and F2α, and serotonin. Patients with extensive metastatic disease frequently develop diarrhea, which may


Surgery_Schwartz

Surgery_Schwartz. other peptides such as calcitonin gene–related peptide, histaminadases, prostaglandins E2 and F2α, and serotonin. Patients with extensive metastatic disease frequently develop diarrhea, which may result from increased intestinal motility and impaired intestinal water and electrolyte flux. About 2% to 4% of patients develop Cushing’s syndrome as a result of ectopic production of adrenocorticotropic hormone (ACTH).Pathology. MTCs typically are unilateral (80%) in patients with sporadic disease and multicentric in familial cases, with bilateral tumors occurring in up to 90% of familial patients. Familial cases also are associated with C-cell hyperplasia, which is considered a premalignant lesion. Microscopically, tumors are composed of sheets of infiltrating neoplastic cells separated by collagen and amyloid. Marked heterogeneity is present; cells may be polygonal or spindle shaped. The presence of amyloid is a diagnostic finding, but immunohistochemistry for calcitonin is more commonly


Surgery_Schwartz

Surgery_Schwartz. and amyloid. Marked heterogeneity is present; cells may be polygonal or spindle shaped. The presence of amyloid is a diagnostic finding, but immunohistochemistry for calcitonin is more commonly used as a diagnostic tumor marker. These tumors also stain positively for CEA and calcito-nin gene–related peptide.Diagnosis. The diagnosis of MTC is established by history, physical examination, raised serum calcitonin, or CEA levels, and FNAB cytology of the thyroid mass. Attention to family history is important because about 25% of patients with MTC have familial disease. Because it is not possible to distinguish sporadic from familial disease at initial presentation, all new patients with MTC should be screened for RET point mutations, pheochromocytoma, and HPT. Screening of patients with famil-ial MTC for RET point mutations has largely replaced using provocative testing with pentagastrin or calcium-stimulated calcitonin levels to make the diagnosis. Calcitonin and CEA are used to identify


Surgery_Schwartz

Surgery_Schwartz. MTC for RET point mutations has largely replaced using provocative testing with pentagastrin or calcium-stimulated calcitonin levels to make the diagnosis. Calcitonin and CEA are used to identify patients with persistent or recurrent MTC. Calcitonin is a more sensitive tumor marker, but CEA is a better predictor of prognosis.Treatment. The ATA published revised guidelines for the man-agement of medullary cancers in 2015.59 A neck ultrasound is recommended to evaluate the central and lateral neck compart-ments and the superior mediastinum. Serum calcitonin, CEA, calcium levels should also be measured, and RET proto-onco-gene mutation testing should be performed. Pheochromocy-tomas need to be excluded. If patients are found to have a pheochromocytoma, this must be operated on first. Primary hyperparathyroidism, if present, is treated at the time of thyroidectomy. These tumors are generally (>50%) bilateral. Total thyroidectomy is the treatment of choice for patients with MTC because of


Surgery_Schwartz

Surgery_Schwartz. hyperparathyroidism, if present, is treated at the time of thyroidectomy. These tumors are generally (>50%) bilateral. Total thyroidectomy is the treatment of choice for patients with MTC because of the high incidence of multicentricity, the more aggressive course, and the fact that 131I therapy usually is not effective.Central compartment nodes frequently are involved early in the disease process, so that a bilateral prophylactic central neck node dissection should be routinely performed. In patients with palpable or imaging-detected cervical nodes, symptoms and signs of distant disease or calcitonin levels >500 pg/mL, additional imaging to include a neck and chest CT and a triple-phase liver CT or contrast-enhanced MRI and an axial MRI/bone scan is recommended to assess for metastatic disease. In patients with no distant disease but nodal involvement, an ipsilateral or bilateral lateral neck dissection (levels IIA, III, IV, and V) is performed. Less aggressive neck surgery should


Surgery_Schwartz

Surgery_Schwartz. disease. In patients with no distant disease but nodal involvement, an ipsilateral or bilateral lateral neck dissection (levels IIA, III, IV, and V) is performed. Less aggressive neck surgery should be consid-ered to preserve speech and swallowing while maintaining locoregional control in patients with limited metastatic disease. The role of prophylactic lateral neck dissection is controversial and may be considered based on calcitonin levels. Some groups favor this procedure if central neck lymph nodes are involved or if the primary tumor is ≥1.5 cm.In the case of locally recurrent or widely metastatic dis-ease, tumor debulking is advised not only to ameliorate symp-toms of pain, flushing, and diarrhea, but also to decrease risk of death from recurrent central neck or mediastinal disease. External-beam radiotherapy is controversial but can be consid-ered for patients with resected T4 disease and for patients with unresectable residual or recurrent tumor and symptomatic bony


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Surgery_Schwartz. disease. External-beam radiotherapy is controversial but can be consid-ered for patients with resected T4 disease and for patients with unresectable residual or recurrent tumor and symptomatic bony metastases. Liver metastases tend to be multiple and are typi-cally not amenable to resection, percutaneous ethanol ablation, or radiofrequency ablation. However, chemoembolization may be helpful in this setting. There is no effective chemotherapy regimen.Various targeted therapies directed against the RET kinase have been investigated for the treatment of MTC.43 Many of these also inhibit VEGF receptor due to their close structural similarities. Sorafenib, sunitinib, lenvatinib, and cabozantinib are some such multikinase inhibitors, whereas axitinib and pazopanib act only on VEGFR. Vandetanib inhibits both targets and is also an EGF receptor inhibitor, and cabozantinib targets c-MET in addition to RET and VEGF receptor. Both drugs are currently approved by the FDA and EMA for the treatment


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Surgery_Schwartz. both targets and is also an EGF receptor inhibitor, and cabozantinib targets c-MET in addition to RET and VEGF receptor. Both drugs are currently approved by the FDA and EMA for the treatment of advanced and progressive MTC based on data that they prolong progression-free survival, in addition to reducing secretion of calcitonin and CEA.60,61 They are recommended as first-line sys-temic therapy in symptomatic patients with advanced MTC. An anti-CEA monoclonal antibody (labetuzumab) also has shown antitumor response in a small group of patients. Patients with recurrent/metastatic disease should be enrolled in well-designed clinical trials.In patients who have hypercalcemia and an increased PTH at the time of thyroidectomy, only obviously enlarged parathy-roid glands should be removed. The other parathyroid glands should be preserved and marked in patients with normocalce-mia, as only about 20% of patients with MEN2A develop HPT. When a normal parathyroid cannot be maintained on a


Surgery_Schwartz

Surgery_Schwartz. The other parathyroid glands should be preserved and marked in patients with normocalce-mia, as only about 20% of patients with MEN2A develop HPT. When a normal parathyroid cannot be maintained on a vascu-lar pedicle, it should be removed, biopsied to confirm that it is a parathyroid, and then autotransplanted to the forearm of the nondominant arm, particularly in patients with MEN2A. Reim-plantation into the sternocleidomastoid muscle is also accept-able for patients with known MEN2B and familial MTC.Prophylactic total thyroidectomy is indicated in RET mutation carriers once the mutation is confirmed. The ATA guidelines stratify mutation into various risk levels to offer recommendations regarding age at which a prophylactic Brunicardi_Ch38_p1625-p1704.indd 165601/03/19 11:21 AM 1657THYROID, PARATHYROID, AND ADRENALCHAPTER 38Figure 38-21. Magnetic resonance imaging scan of a patient with anaplastic thyroid cancer. Note heterogeneity consistent with necrosis.thyroidectomy should be


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Surgery_Schwartz. PARATHYROID, AND ADRENALCHAPTER 38Figure 38-21. Magnetic resonance imaging scan of a patient with anaplastic thyroid cancer. Note heterogeneity consistent with necrosis.thyroidectomy should be performed and to predict phenotypes, including pheochromocytomas.59 In general, in patients with less aggressive mutations (designated ATA moderate-risk), thy-roidectomy may be delayed >5 years, especially if there is a nor-mal annual serum calcitonin, neck ultrasound, less aggressive family history, or family preference. Children with MEN2A and mutations at codon 634 (designated high-risk) are advised to undergo thyroidectomy at <5 years of age, and those with MEN2B-related mutations (designated highest-risk) should undergo the procedure before age 1. Central neck dissection can be avoided in children who are RET-positive and calcitonin-negative with a normal ultrasound examination. When the cal-citonin is increased or the ultrasound suggests a thyroid cancer, a prophylactic central neck


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Surgery_Schwartz. children who are RET-positive and calcitonin-negative with a normal ultrasound examination. When the cal-citonin is increased or the ultrasound suggests a thyroid cancer, a prophylactic central neck dissection is indicated.Postoperative Follow-Up and Prognosis. Patients are fol-lowed by annual measurements of calcitonin and CEA levels, in addition to history and physical examination. Other modalities used to localize recurrent disease include ultrasound, CT, MRI, and more recently, FDG-PET/CT scans. Prognosis is related to disease stage. The 10-year survival rate is approximately 80% but decreases to 45% in patients with lymph node involvement. Survival also is significantly influenced by disease type. It is best in patients with non-MEN familial MTC, followed by those with MEN2A, and then those with sporadic disease. Progno-sis is the worst (survival of 35% at 10 years) in patients with MEN2B. Performing prophylactic surgery in RET oncogene mutation carriers not only improves


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Surgery_Schwartz. and then those with sporadic disease. Progno-sis is the worst (survival of 35% at 10 years) in patients with MEN2B. Performing prophylactic surgery in RET oncogene mutation carriers not only improves survival rates but also ren-ders most patients calcitonin free.Anaplastic Carcinoma Anaplastic carcinoma accounts for approximately 1% of all thyroid malignancies in the United States. Women are more commonly affected, and the majority of tumors present in the seventh and eighth decade of life. The typical patient has a long-standing neck mass, which rapidly enlarges and may be painful. Associated symptoms such as dys-phonia, dysphagia, and dyspnea are common. The tumor is large and may be fixed to surrounding structures or may be ulcerated with areas of necrosis (Fig. 38-21). Lymph nodes usually are palpable at presentation. Evidence of metastatic spread also may be present. Diagnosis is confirmed by FNAB revealing char-acteristic giant and multinucleated cells. Differential diagnoses on


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Surgery_Schwartz. are palpable at presentation. Evidence of metastatic spread also may be present. Diagnosis is confirmed by FNAB revealing char-acteristic giant and multinucleated cells. Differential diagnoses on FNA can include lymphomas, medullary carcinomas, direct extension from a laryngeal carcinoma, or other metastatic car-cinomas or melanoma. When spindle cell elements are present, primary and metastatic sarcomas need to be considered as well. Immunohistochemical markers can aid with excluding other diagnoses. Core or incisional biopsy occasionally is needed to confirm the diagnosis, especially when there is necrotic material on the FNA.Pathology. On gross inspection, anaplastic tumors are firm and whitish in appearance. Microscopically, sheets of cells with marked heterogeneity are seen. The three main histologic growth patterns are spindle cell, squamoid, and pleomorphic giant cell. Tumors may show a predominance of one pattern or a mixture of various patterns. Foci of more differentiated