Left-sided colorectal neoplasms reduced 10-years postcolonoscopy in community setting

Colonoscopies performed in the community setting reduced the risk for advanced neoplasms by 67% in the left colon and rectum; however, no risk reduction was noted for advanced neoplasms in the right colon.

Data on the efficacy of colonoscopy for preventing colon cancer are sparse in the community setting, according to researchers. To assess the efficacy of colonoscopy overall and by anatomical site, they examined data from 2,701 participants with no previous colonoscopy and 586 participants with a previous colonoscopy within ten years prior to the screening colonoscopy.

Among those who had a previous colonoscopy, 6.1% had an advanced neoplasia; 11.4% of those with no previous colonoscopy had an advanced neoplasia.

In site-specific analyses there was a strong and inverse association between having a prior colonoscopy and prevalence of advanced neoplasia in the left-sided colon and rectum, but no association was noted in the right-sided colon.

“The potential limitations of colonoscopy for prevention of incidence and mortality from colorectal cancer that develops in the proximal colon, as identified by this study and others, raise very important questions,” Nancy N. Baxter, MD, PhD, and Linda Rabeneck, MD, wrote in an accompanying editorial.

Baxter is assistant professor in the departments of surgery and health policy, St. Michael’s Hospital at the University of Toronto. Rabeneck is professor of medicine and health policy, Dalla Lana School of Public Health at the University of Toronto.

“Simply put, is the effectiveness of colonoscopy ‘good enough’ for population-based screening? As more observational evidence accumulates, the answer to this question becomes less certain,” they wrote.

Brenner H. J Natl Cancer Inst. 2009;dio:10.1093/jnci/djp436.