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.

Colorectal Cancer Screening for Those Without Symptoms or Known Risk Factors (Average Risk)

According to the American Cancer Society, both men and women should obtain one of the following screening tests for colorectal cancer:

1. Digital rectal exam performed every year after age 50. During this test, the doctor inserts a gloved, lubricated finger into the rectum and feels for abnormalities of the prostate or rectum.
2. 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.
3. 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 three options above, the American Cancer Society prefers yearly fecal occult blood testing along with flexible sigmoidoscopy every 5 years.

1. 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 ½ inch in diameter -- inserted into the rectum to view the rectum and entire colon.
2. Air contrast barium enema performed once every 5-10 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.

Note: Flexible sigmoidoscopy, air contrast barium enema, and colonoscopy are interchangeable. Your doctor will pick which screening test is best for you. However, colonoscopy is the most accurate and offers the possibility of treating polyps when they are found.

Screening Those at Risk for Colorectal Cancer

People with known risk factors for developing colorectal cancer should be screened more frequently, earlier, and with 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:

People With Large or Multiple Polyps

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