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Colonoscopy

Colon cancer is the third most common cancer in the US. All colon cancer begins as a polyp, which means it's fully preventable by screening. For that reason, colonoscopy is recommended at age 50 and, assuming no polyps are found, every 10 years thereafter.

Should a cancerous growth be found, that section of the colon would be removed by a subsequent surgery. Early detection indicates a high cure rate (60-90%), providing another reason to get over your dismay over the idea of the test. The colon and rectum lining is normally smooth and without abnormalities. Colonoscopy can detect and remove polyps before cancer develops, growths can be biopsied or diagnosis can be made of abnormalities such as bleeding or inflammation.

This visual review of your entire colon is done under mild sedation with a colonoscope, which illuminates the lining of the colon and sends the image back to a TV screen for the doctor's review. If polyps are found, instruments are passed through the tube of the scope to remove the growth (or growths) or to take a tissue sample. Because of the sedation, you won't be released from the surgical clinic without someone to drive you home.

Air is used to expand the colon during the procedure; you may feel some pressure or cramping after you get home. Take a walk if you're awake enough; that will speed up the release. Either way, you'll feel normal within a few hours.

Your doctor can also review just the lower portion of the colon -- the sigmoid colon -- via sigmoidoscopy with a flexible sigmoidoscope, which allows the doctor to view the inside of the bowel through a tiny video camera. Sigmoidoscopy can also be used to obtain tissue samples for testing. It's done without sedation, takes less time and does not require someone to drive you home. However, it does not enable the doctor to review the upper part of the colon, so there may still be polyps developing there, and if there are problems a full colonoscopy will still be required.

A lesser option is a hemoccult stool test, which is done by providing fecal material of three consequtive bowel movements on a test card to determine if blood is in the stool. If there's a postive lab result, a colonoscopy will still need to be done. Additionally, false positives are fairly common. So just get the colonosopy already.

If you have external or internal hemorrhoids, the doctor can fix these at the same time by a procedure called hemorrhoid ligation, basically using a sterile rubber band to cut off the blood supply. If this is done, slight dietary changes are required for a week or so (no raw fruits or vegetables), and exercise is minimized for a couple of weeks. This is done easily during the colonoscopy and no additional medical visits are required.

For a successful colonoscopy, your colon needs to be empty. You'll be given a prescription for a laxative to clean out your colon quickly, which you'll do the day prior to the procedure. There are several medicines that can be used; your doctor probably has a preference and will give you a script for that one. Most often this will be a salty liquid, up to a gallon, that you'll drink over the course of a few hours the day before. Some of the medicines are used differently, so follow the pharmicist's instructions. Once you're done with the cleanout, no further food will be eaten that day; you can drink gatorade or other clear liquids, although be careful not to drink anything red as that affects the scoping.

Eat yogurt after procedure to replenish the good bacteria purged during the preparation cleanout.

Here's our recent colonoscopy thread, complete with the requisite jokes, which will give you an indication of what's involved over the two days.

And here's a list of colorectal diseases provided by the American Society of Colon and Rectal Surgeons.

This recent NY Times article discusses the variance of colonoscopy success based upon the skill of the doctor, in particular how much time he or she takes doing the procedure.