Understanding Colon Cancer -- Diagnosis and Treatment

How Is Colorectal Cancer Diagnosed?

Beginning at the age of 50, everyone should be screened regularly for colorectal cancer (earlier screening is recommended for some high-risk groups). There are several options.

The traditional screening routine was for the doctor to perform a digital rectal exam once a year and for you to collect three stool samples to be tested for traces of blood. Also, every three to five years you would receive a sigmoidoscopy and a double-contrast barium enema to look at the lower part of the bowel. If anything were abnormal then you would be referred for a colonoscopy. The colonoscopy is a complete evaluation of the colon and rectum with a scope or long, flexible tube similar to the sigmoidoscope but longer.

Biopsies or tissue samples of any suspicious-looking areas can be obtained during a colonoscopy for laboratory analysis.

Now, most doctors advocate going right to colonoscopy at age of 50. However, other studies are sometimes recommended when a patient is unable or unwilling to undergo colonoscopy.

A noninvasive screening procedure called virtual colonoscopy is available. It does away with the tube and instead uses spiral computed tomography, which produces a three-dimensional image of the colon after it has been emptied and partially inflated with air.

The current American Cancer screening guidelines for colon cancer in an average risk patient begin at the age of 50 and include the following options:

  • Flexible sigmoidoscopy every 5 years, or
  • Colonoscopy every 10 years, or
  • Double-contrast barium enema every 5 years, or
  • CT colonography (virtual colonoscopy) every 5 years.

Alternative screening options include a fecal or stool tests done on a yearly basis.

However, if you are at high risk of colon cancer due to a family history of colon cancer or polyps, screening intervals should begin earlier and be more frequent.

Any suspicious symptoms or abnormalities will alert your doctor to perform a colonoscopy to get a biopsy.

Should a biopsy confirm cancer, imaging tests using chest X-rays and CT scans of the abdomen, pelvis, and possibly chest are performed to find out whether the cancer has spread to other sites.

Blood tests will also be ordered to find out how well the liver and kidneys are functioning, to determine if you are anemic, and to measure the blood level of a substance called carcinoembryonic antigen (CEA), often found in higher-than-normal concentration in the presence of colorectal cancer, especially if it has spread.



What Are the Treatments for Colorectal Cancer?








Radiation therapy can be used in people with colon cancer when the tumor has attached to another organ in the abdomen, or if a tumor is found near the margins of the cancer that was removed.

Chemotherapy drugs are used to treat various stages of colorectal cancer. They include 5-flurouracil, capecitabine (Xeloda), irinotecan (Camptosar), and oxaliplatin (Eloxatin). These drugs are commonly used in combination with one another. Chemotherapy can also be administered directly into the liver if the colon cancer has metastasized there.

The FDA has approved five drugs for treating colon cancer that work an entirely different way. The drugs, bevacizumab (Avastin), cetuximab (Erbitux), panitumumab (Vectibix), regorafenib (Stivarga), and ziv-aflibercept (Zaltrap) are a form of cancer therapy called biologic therapy. These drugs work by blocking the cancer’s blood supply or blocking a protein made by the cancer to enhance its growth. They can be used to treat advanced colorectal cancer that has spread (metastasized) to other parts of the body.

Once cancer of either the colon or rectum is in remission, follow-up exams to check for recurrence are essential. But hundreds of thousands of people are living comfortable, normal lives even after colorectal surgery and a colostomy. Although adjusting to life after a colostomy requires time, support, and understanding, people with stomata have discovered for the most part they can eat, play, and work as well as they did before.




American Cancer Society. 

National Cancer Institute. 

WebMD Medical Reference from the American College of Physicians: “Section 12 V Colorectal Cancer.” 

FDA: "FDA approves new treatment for advanced colorectal cancer."

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