Overview of Colonoscopy Risks

The Cost-Benefit Analysis of Colonoscopies

A colonoscopy calendar reminder.
A colonoscopy calendar reminder.. Catherine Lane/Getty Images

So, you've heard ad nauseam how great colonoscopies are at preventing colon cancer. But your skeptical side (perhaps egged on by the child in you who insists you don't need screening) says there must be more to the story. Here are some facts to help you decide if the risks from a colonoscopy are worth the benefits.

What Are the Risks of a Colonoscopy?

Colonoscopy risks include heavy bleeding, intestinal perforation (poking a hole in the gut), infection, adverse reaction to the sedatives, and bowel infection.

However, these complications rarely occur and are even less common with colonoscopies that don't involve polyp removal.

How Often Do Colonoscopy Risks Become Colonoscopy Complications?

Rarely, but what does that mean exactly? A study published in the Annals of Internal Medicine provided some.

When researchers reviewed colon cancer screening data from 1966 to 2001, they discovered the following:

  • Perforation occurred in 0.029 percent to 0.72 percent of colonoscopies.
  • Heavy bleeding occurred in 0.2 percent to 2.67 percent of colonoscopies.
  • Death occurred in about 0.003 percent to 0.03 percent of colonoscopies.

Put another way:

  • Perforation occurred in about 1/3,450 to 1/139 colonoscopies.
  • Heavy bleeding occurred in about 1/500 to 1/37 colonoscopies.
  • Death occurred in about 1/30,000 to 1/3,000 colonoscopies.

How Can You Minimize Colonoscopy Risks?

Proper colonoscopy prep will help make sure your doctor has a clear view while navigating through your colon.

Some other things I'd suggest:

  • Choose a board-certified gastroenterologist to perform the procedure as opposed to your family doctor.
  • Make sure an experienced anesthesiologist will be present in case you have an adverse reaction to the sedative.
  • Have the procedure in or near a hospital. If bowel perforation occurs, you want to be able to get it repaired right away.

    You may also want to ask your doctor if he plans to apply abdominal pressure during the colonoscopy. A study published in Gastroenterology Nursing found that colonoscopy risks, duration, and discomfort could be minimized if the doctor used certain abdominal pressure techniques during the procedure.

    Do Colonoscopy Risks Outweigh the Procedure's Benefits?

    That's one for you and your doctor to discuss, but the general answer is yes. Colonoscopies and removal of precancerous polyps during the procedure are among the most successful tools available in the prevention of cancer. But, if your medical history indicates a colonoscopy isn't needed, then it may be more test than you need and put you at unnecessary risk.


    Common Questions about Colonoscopy. American Society for Gastrointestinal Endoscopy. Nov. 2005. 13 Oct. 2006.

    Farley, D. and Bannon, M. "Management of Colonoscopic Perforations." Mayo Clinic Proceedings 72.8 (Aug. 1997): 729-733. PubMed. 13 Oct. 2006.

    Makins, R. and Ramptom, D. "Patients' Understanding of Colonoscopy Risk is Suboptimal." Gut 53 (2004): 915. 13 Oct. 2006.

    Pignone, M. and Rich, M. "Screening for Colorectal Cancer in Adults at Average Risk: A Summary of the Evidence for the U.S. Preventive Services Task Force." Annals of Internal Medicine 137.2 (Jul. 2002): 132-141. PubMed. 13 Oct. 2006.

    Pignone, M. and Rich, M. Summary of the Evidence: Screening for Colorectal Cancer in Adults at Average Risk. Agency for Healthcare Research and Quality. 13 Oct. 2006.

    Prechel, J. and Young, C. "The Importance of Abdominal Pressure During Colonoscopy: Techniques to Assist the Physician and to Minimize Injury to the Patient and Assistant." Gastroenterology Nursing 28.3 (May 2005): 232-236. PubMed. 13 Oct. 2006.

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