FAMILY MEDICINE® COLUMN

By John C. Wolf, D.O.Associate Professor of Family Medicine Ohio University College of Osteopathic Medicine

DESPITE READER'S CONCERN, COLONOSCOPY BENEFITS OUTWEIGH RISKS

Question: I'm scheduled to have a colonoscopy, which my doctor assures me has few risks associated with it. However, a friend had a perforation from this procedure and nearly died. I'm confident about my doctor and my need for the examination, but I am unsure about how to assess its real risk. How great is the risk of having a serious complication with colonoscopy?

Answer: Colonoscopy is an examination of the colon (large intestine) that is principally done to look for signs of colon cancer and other colon abnormalities. It is an important procedure because colon cancer strikes about 30 out of each 100,000 people in the Northeast, with slightly lower rates in other parts of the U.S. About 130,000 individuals are diagnosed with colon cancer each year and more than 56,000 die from it.
To date there is no perfect test for detecting this killer when it is small and usually curable, but colonoscopy is certainly a great step in that direction. You see, over 90 percent of colon cancers develop from benign colon growths called polyps, and these polyps cause no symptoms. By looking at the colon's surface, these polyps become as apparent as moles, warts and other skin abnormalities are to the careful examination of the skin.

OK, as I'm sure you've figured out, colonoscopy involves the passage of an almost five-foot long instrument through the anus and on through the entire length of the colon to where it joins the small intestine. The tip of this high-tech fiber optic marvel sends an image to a TV screen that the doctor can look at to see the surface of the colon. The individual twists and folds of the colon are carefully evaluated as the instrument is passed and then withdrawn.

As you have probably guessed, this procedure is uncomfortable. Therefore, the only common "complication" is pain. To deal with this, most doctors administer one or more drugs to make the procedure tolerable. I know I've recently had a colonoscopy and don't remember a thing about it because of the medicine I was given. The drugs, however, do add a very small but real risk of allergic reaction to the drug(s), or circulation or breathing problems from the direct effect of the medicine. These problems, though uncommon, are well known. Therefore, if these drugs are required for your exam, your doctor will monitor both oxygen levels in the blood and your EKG. When looking at the benefits versus risks, the scale tips dramatically toward the benefits side.

The complication your friend had, perforation, occurs when the tip of the scope or biopsy instrument breaks through the wall of the colon. This is most common when a large polyp must be removed or when there is significant weakening of the colon wall because of disease. The perforation produces a passageway for colon bacteria to enter into the sterile abdominal space. A perforation requires surgery to close the rent in the colon and antibiotics to prevent widespread infection. Fortunately, only about 0.1 percent of colonoscopies result in perforations. And, the rate is even less when the exam is performed by a highly skilled individual.

Rectal bleeding after colonoscopy occurs in about 0.2 percent of cases. This makes bleeding the most common complication. This risk increases in those who have bleeding disorder or those who take aspirin or other medicines that increase bleeding. Fortunately, most episodes of bleeding stop with minimal treatment such as fluid replacement. Only rarely are transfusions or additional procedures, including surgery, necessary to stop it.
It is wise to be aware of the risks associated with every medical decision -- or life decision for that matter. Make an informed choice. I talked to my doctor and reviewed the medical literature before choosing to have colonoscopy. You make up your own mind.

"Family Medicine" is a weekly column.

To submit questions, write to John C. Wolf, D.O., at Post Office Box 110, Athens, Ohio 45701.

Past columns are available online at http://www.FamilyMedicineNews.org.