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 | Colon Cancer
By Michael Spilane, MD
Too many older folks have a fatalistic "If I get it, then I get it" attitude about cancer. They hope to dodge the "big C", but make no attempt to improve their chances. Colon cancer is one of the Cs where action can make a difference, maybe even a big difference. In the United States, colon cancer is the second most common type of cancer in women (after breast cancer) and the third most common in men (after lung and prostate). Across gender, colon cancer ranks as the number one cancer killer in those who do not smoke. At age 65, an individuals overall risk of eventually developing a colon cancer is about 10%.
Increasing age is the biggest risk factor for colon cancer. Other factors that elevate the risk include a history of colon cancer in a close family member, a personal history of colon cancer or colon polyp, and the presence of certain inflammatory bowel diseases. For unknown reasons, Afro-American men and women have an increased risk for colon cancer. The tumors can develop at an early age in those with hereditary colon polyposis or ulcerative colitis.
Medical experts generally agree that the vast majority of colon and rectal cancers develop from colon polyps, mushroom like growths that protrude from the bowel wall. Polyps are common, but some have the potential to enlarge and eventually turn malignant. The rationale for effective prevention of colon and rectal cancer is based on finding and removing the polyps before they become cancerous, or before a malignant transformation has resulted in the spread of cancer cells beyond the polyp itself.
Screening for colon cancer is now considered a vital part of health maintenance for older individuals. The most conclusive test is colonoscopy. A gastroenterologist uses a long flexible tube equipped with fiberoptic illumination to examine the entire colon. If polyps are discovered, they are snared and removed during the procedure. The polyps, along with biopsies of any other suspicious growths, are submitted to a pathologist and examined for signs of cancer. Colonoscopy requires the use of purgatives to vigorously cleanse the colon on the day before the procedure. The test itself is uncomfortable but tolerable, and usually can be completed by the physician within thirty minutes. Colonoscopy entails some risk, but in the hands of a skilled gastroenterologist the risk is very low.
A flexible tube sigmoidoscopy, or "procto", avoids some of the discomfort associated with colonoscopy, but is less effective in screening for polyps and colon cancer. Only the rectum and distal 20% of the colon are examined. If this region of the bowel is clear of polyps, it is probable (but uncertain) that the entire colon is fine. If polyps are detected, the doctor may recommend a colonoscopy to examine the entire colon. A sigmoidoscopy is very safe, quite tolerable, and requires a less vigorous colon purge than for a colonoscopy.
Checking stool samples for blood is an alternative to actually looking inside the bowel with an instrument. The presumption is that large polyps-the ones most likely to turn malignant or to be malignant-leak microscopic bits of blood into the bowel. The blood will not be noticed by the patient, but can be detected by a simple test of the stool. This is an acceptable screening tool for colorectal cancer, but does not approach the detection sensitivity of direct bowel examination using an instrument.
Medicare has finally seen the light and now covers the cost of colonoscopy and other screening tests for colon cancer. It will pay for one colonoscopy every ten years, or every two years if defined extra risk factors exist. All medical experts agree that older adults should have screening tests for colon cancer, and most recommend that the tests start at age 55. Don't wait for your personal physician to advise a colonoscopy or sigmoidoscopy to screen for colon cancer-put the issue on your own agenda for the next visit.
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