Colorectal Cancer Screening and Prevention Technique (page 1 of 4)
By Sandra J Beck, M.D.
Division of Colon and Rectal Surgery

Screening
The challenge to us all is to prevent colon and rectal cancer. This can be accomplished if one accepts the polyp to cancer progression and that screening for and removal of polyps before they become cancers results in fewer cancers. Screening has been somewhat controversial in the past because the gold standard of screening — colonoscopy — is invasive and expensive. Recently, new guidelines for screening have been proposed based on risk stratification.

For patients in high-risk groups such as those with Familial Adenomatous Polyposis (FAP), ulcerative colitis or other polyposis syndromes, screening begins at an earlier age and should be provided at frequent intervals. For the general population, screening should begin at age 50 for both men and women. In patients with a family history of colon or rectal cancer, screening should be initiated 10 years prior to the age at which their family member was diagnosed. Screening protocols (see Table) utilizing fecal occult blood testing(FOBT), sigmoidoscopy and barium enemas in various combinations have been recommended for low-risk patients. However, the gold standard remains colonoscopy because it allows the visualization of the entire colon and is also therapeutic in that the endoscopist, person performing the colonoscopy, can remove small polyps, biopsy larger masses and identify and biopsy inflammatory conditions. The challenge of effective screening is patient and physician compliance with these recommendations. The general population perceives these procedures as painful and embarrassing, thus many people delay or often refuse to have the procedure altogether. The challenge to clinicians is to educate the patients about their bodies, so that the patients recognize changes in their bodies, and to allay patient fears about invasive tests such as colonoscopy and digital rectal exam(DRE). While colonoscopy is invasive, it is usually performed with conscious sedation and many patients do not remember the procedure. The bowel preparation required is often remembered as the worst part of the process.

The future of screening lies in noninvasive imaging of the colon and other tests such as fecal DNA testing. The current status of noninvasive imaging such as virtual colonoscopy or CT colonography will be discussed later. Recent reports on detection of colon cancer via fecal DNA studies are promising, and this may be an acceptable screening test in the future. However, these tests are still experimental and are not widely available.