Screening Guidelines for Colorectal Cancer

Getting regular doctor check-ups may be the best way to prevent colorectal cancer. Early detection of any abnormal cells allows for prompt treatment and makes curing colorectal cancer more likely. Experts in the medical profession have created screening guidelines based on a person's risk factors, however doctors disagree on which screening test is best.

Screening recommendations for those without known risk factors (average risk)
According to the American Cancer Society, both men and women should obtain one of the following:

• Fecal occult blood test performed once a year, every year after age 50. This is a simple at home test that checks for blood in the stool that you may not be able to see.
• Flexible sigmoidoscopy performed every 5 years beginning at age 50. This is an outpatient procedure for examining the inside of the lower portion of the large intestine, called the sigmoid colon. A special instrument with a tiny camera attached is used.

Of the two options above, the American Cancer Society prefers yearly fecal occult blood testing along with flexible sigmoidoscopy every 5 years. Other options for colorectal screening include:

• Colonoscopy performed once every 10 years starting at age 50. This is an outpatient procedure in which a physician uses a long, flexible instrument -- about Ѕ inch in diameter -- inserted into the rectum to examine the rectum and entire colon.
• Air contrast barium enema performed once every 10 years starting at age 50. During this procedure a barium enema is given and then air is blown in to make the barium spread over the lining of the colon, producing an outline of the colon on X-ray. This helps to reveal any irregularities in the lining, such as a polyp.
• Virtual colonoscopy is a way of examining the colon by reconstructing an image from the results of computerized tomography (CT scan). It is a non-invasive way of examining the colon and shows real promise in accurately detecting significant polyps and cancers.
• DNA stool testing has recently been reported as a major improvement over hemoccult testing. The test extracts DNA for a stool sample and looks for mutations that are likely to have come from a cancer. Recent results report that the test detects 56% of cancers.

Note: Colonoscopy is the most accurate screening test and offers the possibility of treating polyps when they are found. It is a covered expense by Medicare and more private insurance companies are covering it as well. Most professional medical societies concerned with colorectal cancer now recommend colonoscopy as the best screening test.

Screening for those at risk for colorectal cancer
People with known risk factors for developing colorectal cancer should be screened more frequently, earlier, and with the more reliable tests. Your doctor can advise you as to what is best for you. The following are recommendations from the American Cancer Society.

Screening recommendations for people with a history of pre-cancerous polyps (adenomas) or cancer of the colon include the following:

• Colonoscopy at the time of initial polyp diagnosis
• Total colonic examination within 3 years after polyp removal; if normal, screen according to average risk recommendations

• Colonoscopy at the time of initial polyp diagnosis
• Total colonic examination within 3 years after polyp removal; if normal, repeat every 5 years

• Total colonic examination within one year; if normal, repeat in 3 years; if still normal, repeat in 5 years

Screening for those at risk for inherited colorectal cancer
The screening recommendations for people who have close family members (first-degree relatives including parents, children, or siblings) with colorectal cancer or polyps are based on the age and number of relative(s) affected.

Screening begins at age 40, or 10 years earlier than the youngest person in the family who was diagnosed with colon cancer or polyps. For example, if you have a brother who was diagnosed at age 42, you should start getting screened at age 32. For screening purposes, it is recommended that you undergo a colonoscopy every 5 years.

• In puberty, begin surveillance with endoscopy; counseling to consider genetic testing; and referral to a specialty center
• If genetic test is positive or polyposis is confirmed, consider colectomy; otherwise, screen with endoscopy every 1-2 years

• At age 21, colonoscopy and counseling to consider genetic testing; referral to a specialty center
• If genetic test is positive or if you have not had genetic testing, colonoscopy every 2 years until age 40, then every year

• Colonoscopy with biopsy starting 8 years after the start of pancolitis, (colitis occurring throughout the colon), or 12-15 years after the start of left-sided colitis; repeat every 1-2 years