Glossary of Terms

Adenocarcinoma: Specific form of breast cancer arising in gland-forming tissue

Alopecia: Hair loss, a common side effect of chemotherapy

Areola: The pigmented area around the nipple

Aromatase Inhibitors (AIs): Type of hormone therapy for breast cancer patients with estrogen receptor positive breast cancer. AIs decrease the circulating estrogen in a woman’s body by preventing the aromatase enzyme from converting androgen (androstenedione and testosterone) into estrogen (estrone and estradiol), which is the principal source of estrogen for postmenopausal women. These drugs should only be prescribed to women who are postmenopausal or who have had an oophorectomy.

Axillary lymph nodes:  Glands in the armpit that fight harmful invaders such as bacteria.  The presence of breast cancer cells in these lymph nodes generally indicates that cancer is more likely to spread elsewhere in the body.

Axillary lymph node dissection:  Surgical removal of lymph nodes in the armpit area.

Atypical hyperplasia: A condition that occurs when cells become abnormal in number, size, shape, and appearance.

Benign: Not cancerous

Bilateral: Involving both sides, such as both breasts

Biopsy: Removal of tissue, either with a needle or through surgery, to determine if a mass is benign or malignant; this term does not indicate how much tissue will be removed.

Bone marrow: Tissue that fills the center of bones

BRCA-1 and BRCA-2:  Normal genes which can carry a mutation that may increase a person’s risk of developing breast cancer.

Breast reconstruction: Creation of an artificial breast by a plastic surgeon after mastectomy

Calcification: Small calcium deposits in the breast tissue that can be seen by mammography

Carcinogen: A substance that causes cancer

Carcinoma: Cancer arising in epithelial tissue (outer layer tissue such as skin, glands, and lining of internal organs); most cancers are carcinomas.

Chemotherapy: Treatment of disease with certain chemicals; the term usually refers to cancer cell killing drugs given for cancer treatment.

Core biopsy: Type of needle biopsy where a small core of tissue is removed from a lump without surgery.

Cyst: Fluid-filled sac

Dissection:  Surgical removal

Ductal carcinoma in situ (DCIS): Ductal cancer cells that have not grown outside of their site of origin, sometimes referred to as pre-cancer.

Estrogen: Female sex hormone produced by the ovaries, placenta, and adrenal glands.

Estrogen receptor-positive (ER+):  Tumor status indicating sensitivity to hormones; breast cancer patients with ER+ tumors are often treated with chemical estrogen blockers such as tamoxifen or anastrozole.

Fine needle aspiration:  Procedure in which a surgeon uses a needle and syringe to remove cells from tissue to determine whether cancer cells are present.

Genetic: Relating to genes or inherited characteristics

Hyperplasia: Excessive growth of cells

In situ: Literally, in the site of; in regard to cancer, in situ refers to tumors that have not spread past their site of origin.

Invasive cancer: Cancer that is capable of going beyond the site of origin and invading neighboring tissue.

Lesion:  A point or patch of a disease

Lumpectomy: Surgery to remove a cancerous tumor from the breast and a small rim of normal tissue around it.

Lymph nodes:  Glands found throughout the body that fight harmful invaders such as bacteria; the presence of cancer cells in lymph nodes adjacent to a primary tumor generally indicates that cancer is more likely to spread elsewhere in the body.

Lymphedema: Swelling of the arm that can follow axillary node removal as part of breast cancer surgery; it can be temporary or permanent and occur immediately or any time after surgery.

Malignant: Cancerous

Mastectomy: Surgery to remove the breast

  • Partial: A form of breast-conserving therapy in which the part of the breast containing the tumor is removed.
  • Radical: Surgical removal of a breast along with the nipple, overlying skin, muscle beneath the breast, and lymph nodes.
  • Preventive (aka prophylactic): Can be a total mastectomy with the removal of the entire breast and nipple, or it may be a subcutaneous mastectomy, where the breast is removed but the nipple is left intact.

Metastasis: Spread of cancer to an organ beyond the location in which it originated.

Oncogene: Gene with the potential to cause cancer; these can be activated by carcinogens and cause cells to grow uncontrollably.

Oncology:  The study of cancer

Pathologist: Health care provider who specializes in examining tissue and diagnosing disease.

Progesterone receptor-positive (PR+): Tumor status indicating sensitivity to progesterone; patients with PR+ tumors are often treated with hormone suppression drugs.

Radiation therapy: Treatment with high-energy rays (x-rays) to kill cancer cells

Radiologist:  An individual specializing in the use of X-rays to diagnose or treat disease

Recurrence: Return of cancer after it seems to have completely disappeared

Remission: Disappearance of detectable disease

Sentinel Node Biopsy: Removal of only one or a few lymph nodes to determine whether breast cancer is likely to spread elsewhere in the body.  The sentinel node is the first lymph node to which a tumor drains and therefore, the most appropriate lymph node to examine for evidence of cancer.

Side effect: Unintentional or undesirable secondary effect of treatment

Staging of breast cancer:  Stage is determined by the size of the tumor and the presence or absence of cancer cells in lymph nodes and in other parts of the body.  Staging is important because it establishes how far the disease has spread, helping doctors to develop a treatment plan.

  • Stage 1:  The tumor is ¾”or less with no evidence of spread to lymph nodes or distant sites.
  • Stage 2A: A tumor is less than ¾” with spreading to lymph nodes, or is a large tumor and no spreading to lymph nodes. 
  • Stage 2B:  A tumor is between ¾” and 2” with spreading to lymph nodes, or is a very large tumor without spreading to lymph nodes. 
  • Stage 3A:  A big tumor (over 2”) with spreading to lymph nodes or fixation of lymph nodes to one another or other structures. 
  • Stage 3B:  If the lymph nodes inside the chest are involved or the tumor extends into the chest wall or involves and ulcerates the skin. 
  • Stage 4:  There are distant metastasis (to bone, liver, or lung for example) or skin, and chest wall involvement beyond breast area. 

Tamoxifen (Nolvadex®):  Drug that blocks hormones from stimulating cell or tumor growth in the breast, reducing the risk of recurrence for women whose breast cancer is receptive to estrogen.

Triple-negative breast cancer (ER-/PR-/HER2 -): Tumor status indicating a lack of sensitivity to estrogen, progesterone, and Her2; because these cancer cells are not hormone-driven, they will not respond to treatment that blocks the effects or production of these hormones.

Tumor: Abnormal mass of tissue; the tumor can be benign or malignant.

Ultrasound:  The use of sound waves to obtain images for medical diagnosis.


* Definitions taken from our newsletters and from Love, S., Dr. Susan Love’s Breast Book (5th Ed.), Perseus Publishing: MA. 2010., and WebMD.