Understanding colon testing

Various procedures are available for detecting cancer and other problems in the colon or rectum, the lowest parts of your digestive tract. Early detection of cancer is essential, offering a high likelihood of cure. It is important not to forego these tests because of embarrassment or unpleasantness. They are critical for saving lives.

1. About the test. This is an inexpensive method for detecting the presence of hidden (or occult) blood in your feces, which cannot be seen with the naked eye. Blood may be a sign of colon cancer or a precancerous polyp in the gastrointestinal tract.
2. How is it done? Your doctor will give you a packet for taking samples of your stool at home. Using a wooden applicator, smear a stool sample on a specimen card on three consecutive days then promptly drop the samples at your doctor’s office or mail them to a lab for analysis.
3. How often is it needed? Experts recommend that everyone have a fecal occult blood test every two years starting at age 50.

1. About the test. Your doctor performs sigmoidoscopy to check for polyps, cancer, bowel inflammation, hemorrhoids and other problems in the lower third of your colon.
2. How is it done? At your doctor’s office, undress and lie on your side on a table with your knees drawn up, a cloth draped over you for modesty. Your doctor will first perform a digital rectal exam. Then a thin, flexible, lighted viewing tube called a sigmoido-scope is inserted into your anus and rectum and advanced up the lower 60 centimetres (two feet) of your colon to view the walls of your bowel. If polyps are found, they may be removed and sent to a lab. Sometimes sedatives are given for mild cramping. The procedure takes 10 to 15 minutes. You may have some gas afterwards. If you have any fever, bleeding or pain, call your doctor.
3. How often is it needed? The Canadian ­Cancer Society recommends screening with sigmoidoscopy after a positive FOB test. If abnormalities are found, a follow-up colonoscopy may be required.

1. About the test. Unlike a sigmoidoscopy, a colonoscopy checks the entire length of the colon. This exam is considered the gold-standard technique for visualizing the colon. Colonoscopy is performed by a gastro­enterologist who looks for ulcers, obstructions, polyps, tumours, inflammation and other bowel problems.
2. How is it done? Your doctor will give you instructions on fasting, laxatives and enemas for the day or two preceding the procedure. You may be given a mild intravenous sedative before the doctor snakes a flexible viewing tube through your anus and along the entire length of your colon. The procedure is usually painless and takes 30 to 60 minutes. If a polyp or suspicious area is found, it can be removed or a small sample taken (biopsied) for later examination. If you are awake during the procedure, you may experience slight cramping, but this dissipates soon after the procedure is finished. You may feel tired or groggy for several hours afterwards, and a friend will need to escort you home from the hospital. If you experience any fever, bleeding, or pain call your doctor.
3. How often is it needed? Follow-up colonoscopy is required if polyps, tumours or other abnormal findings are detected via the fecal occult blood test, sigmoidoscopy or digital rectal exam.