Preparation for the procedure begins the day before and involves limiting the diet to clear liquids and ingesting two doses of laxative several hours apart to empty and clean the colon and rectum.
The test is an outpatient procedure.
The patient typically is sedated before the gastroenterologist inserts a thin, flexible, lighted tube, or colonoscope, into the rectum and colon. That enables the doctor to look at the lining of the colon, take pictures, and see whether there are polyps that need to be removed. The colonoscopy usually lasts about 30 minutes, possibly longer if polyps are removed.
An alternative procedure is the virtual colonoscopy, which uses computed tomography — a CT scan — to enable a radiologist to see the interior of the colon in a three-dimensional computer image. However, the procedure is not covered by most insurance companies; and if a polyp is detected, the patient must undergo a conventional colonoscopy to have it removed.
“If a polyp is removed, it is sent to a pathologist for review under a microscope,” Hell says. “The results usually come back in four to five days.”
The incidence of colon cancer increases with age, particularly after 50, so the American Cancer Society recommends people with no family history of the disease have their first screening then.
If no issues are found, the test should be repeated every 10 years. If you have a family history of the disease or other risk factors, talk to your doctor about when to have your first screening and how often it should be done.