Public Release: 

Perforation twice as frequent during colonoscopy as during sigmoidoscopy

Journal of the National Cancer Institute

The risk of perforation to the colon after a sigmoidoscopy, although small, is about half the risk of a perforation after a colonoscopy, according to a new study comparing the two procedures used for the early detection of colorectal cancer. The findings appear in the February 5 issue of the Journal of the National Cancer Institute.

A colonoscopy is used to check the entire length of the colon for cancer or precancerous abnormalities. One potential complication from colonoscopy is perforation, or damage to the colon wall. Past studies have attempted to study the rates of colon perforation from colonoscopy but have been limited by small sample size. A similar technique called sigmoidoscopy is less expensive than colonoscopy and is limited to the section of the colon closest to the rectum. Sigmoidoscopy is expected to have a lower incidence of perforation, but the data to support this are limited.

To compare the risks of perforation associated with colonoscopy and sigmoidoscopy in people age 65 and older, Nicolle M. Gatto, of the Mailman School of Public Health at Columbia University, Alfred I. Neugut, M.D., Ph.D., of Columbia University and New York-Presbyterian Hospital, and their colleagues used a database of Medicare beneficiaries to identify people who were cancer-free and had undergone at least one colonoscopy or sigmoidoscopy between 1991 and 1998. The authors then calculated the incidence and risk of perforation within 7 days of the procedure.

Of 39,286 colonoscopies included in the analysis, there were 77 perforations (1.96 perforations per 1,000 colonoscopies), compared with 31 perforations in 35,298 sigmoidoscopies (0.88 perforations per 1,000 sigmoidoscopies). After adjusting for factors such as age, race, and sex, the risk of perforation from sigmoidoscopy, which examines less than half the colon, was about half that from colonoscopy. In addition, the authors found that roughly 5% of those who had a perforation died within 14 days of the procedure.

The authors noted that the difference in risk between the two procedures has been narrowing because the risk of perforation from colonoscopy has decreased over the years, possibly from improvements in technology and in the training of people performing the procedures.

The authors say that their results should be useful to clinicians weighing the risks and benefits of screening to choose the right test for each individual patient and to public health and policy officials setting guidelines for colorectal cancer screening programs.

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Contact: Alicia Park, New York-Presbyterian Hospital, 212-305-5587, alk9007@nyp.org or Annie Bayne, Columbia University, 212-305-3900, as862@columbia.edu.

Gatto NM, Frucht H, Sundararajan V, Jacobson JS, Grann VR, Neugut AI. Risk of perforation after colonoscopy and sigmoidoscopy: A population-based study. J Natl Cancer Inst 2003;95:230-6.

Note: The Journal of the National Cancer Institute is published by Oxford University Press and is not affiliated with the National Cancer Institute. Attribution to the Journal of the National Cancer Institute is requested in all news coverage.

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