Colorectal Cancer Screening

Alan Smith, MD
Wenatchee Valley Clinic, Wenatchee, Washington

Colorectal cancer (CRC) is the second leading cause of cancer death in the US for men and women combined. It is also among the most preventable cancers, and there is growing public awareness of the importance of screening.

While women are generally quite informed about the importance of cancer screening utilizing regular mammograms and PAP smears, men need to be aware of similar strategies for prevention and early detection of prostate and colorectal cancer.

Colorectal cancer (CRC) is the second leading cause of cancer death in the US for men and women combined. It is also among the most preventable cancers, and there is growing public awareness of the importance of screening. A useful strategy for CRC screening is to consider one’s relative risk — normal or average risk, or higher risk based on personal and family medical history which will help determine the most appropriate screening strategy. A normal risk individual is one with no prior history of colon cancer or polyps, no history of inflammatory bowel disease, and no significant family history of colon cancer or polyps.

Relative risk based on one’s family history can be further stratified based on how many family members (especially parents or siblings) have had colon cancer or polyps, and at what age. In brief, the highest family risk would be for a patient who has had more than one first-degree relative with one diagnosed at less than 60 years of age. There are a few known inherited syndromes that place patients at very high risk of CRC; patients with strong family histories of polyps and cancers should discuss the possibility of such a condition with their doctor. Another reason to discuss this with one’s physician is the unusually high rate of other cancers in such families including uterine, gastric, ovarian, kidney, and small intestinal cancers.

There are several options available for CRC screening, including checking stool specimens for tiny amounts of blood (fecal occult blood testing or FOBT), flexible sigmoidoscopy, complete colonoscopy, or air-contrast barium enema (ACBE or xray “lower GI” study). While efficacy for these strategies may vary a bit, it must be emphasized that any of these accepted screening options are much better than no screening. The tables at the end of this article on pages 31 and 32, summarizes the recent recommendations of the American Gastroenterological Association, the American Cancer Society, & the American College of Gastroenterology. Note the varying recommendations depending on familial risk, which is summarized in the first table. The second table provides you a quick glance at the recommended surveillance for people who have had colorectal cancer or pre­cancerous polyps.

Colonoscopy is emerging as the dominant technique for CRC screening, but this is an evolving area and will be influenced by overall cost and availability. “Virtual Colonoscopy” using rapid CT (Xray) is being evaluated but cannot yet be endorsed by any group publishing CRC screening guidelines. Genetic testing is now available for the 3-5% of patients with possible inherited CRC syndromes. The utilization of such tests requires appropriate expert genetic counseling to be useful in clinical practice.

What can patients do to affect their own risk of CRC? There is sentiment that low-fat, high-fiber diets are beneficial. This has been difficult to prove in short- term studies, but seems to be a very appropriate good health measure. The role of calcium supplements to help prevent CRC is unproven. Smoking is a recognized risk factor in the develop­ment of gastrointestinal cancers and constitutes yet another argument against smoking.

The above emphasizes screening for CRC. Screening means checking people with no symptoms for possible polyps or cancers. It is very different than a medical evaluation of symptoms. Patients should always seek medical evaluation of any sort of gastrointestinal bleeding, a change in bowel habits, unusual abdominal pain, or really any symptom that is concerning. Average risk men should discuss CRC screening with their doctor starting at age 50. For higher risk men screening should start earlier. Please discuss this with your doctor.

Click Here for a:

Colorectal Prevention Guide Part A

Colorectal Prevention Guide Part B

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