Screening for Those at Increased Risk of Colorectal Cancer

If you are at high risk of colorectal cancer, or if other screening tests (FOB test or flexible sigmoidoscopy) indicate an abnormality, your health care provider will recommend a colonoscopy.

Colonoscopy
Colonoscopy is considered the gold standard when it comes to diagnosing colorectal cancer. A colonoscope consists of a long flexible tube with a tiny video camera on the end. It is similar to a sigmoidoscope except it is longer and allows your doctor to view the entire colon. With this instrument, a physician can inspect the entire colon and rectum, and remove polyps or biopsy any abnormalities, which can then be examined in the lab.

If you are having a colonoscopy, you will be given a preparation the day before your procedure, to clear your colon. A colonoscopy is usually done as a day surgery procedure. You will generally be given a mild sedative intravenously. The procedure takes about 30 minutes. It may cause mild bloating and discomfort for a few hours following the procedure.

Colonoscopy is recommended when abnormalities are found using FOB test or flexible sigmoidoscopy. Regular colonoscopies are also recommended for those with family or personal histories of colorectal cancer, polyps or inflammatory bowel disease, as outlined in the previous section. This may be at one- to five-year intervals, depending on your situation.

Barium Enema
Another procedure sometimes used to examine the colon is a barium enema. This can identify abnormalities in the lining of the bowel. An enema is used to partially fill the colon with a chalky substance. Air is then added to expand the colon and x-rays are taken.

Your doctor will tell you how to prepare for the procedure. Test preparations include a diet of clear liquids, a laxative and an enema, the day before your procedure, to clear your colon and rectum.

Barium enemas are done in the radiology department of a hospital or clinic. The procedure usually takes 45 minutes to an hour and may cause some bloating and discomfort.

It is not possible to remove polyps or to take biopsies using a barium enema. Generally, if an abnormality is found, a colonoscopy will be recommended so that the abnormality can be biopsied.