Colonoscopy Shown to Lower Risk for Right- and Left-Sided Cancers

Colonoscopy is associated with a near-80% reduction in risk for colorectal cancer, according to a population-based case-control study published in the Annals of Internal Medicine.


German investigators ascertained colonoscopy histories of some 1700 patients with a first diagnosis of colorectal cancer and 1900 controls without a history of colorectal cancer. After adjustment for covariates including level of education, smoking status, body-mass index, and use of NSAIDs or hormone replacement, a history of colonoscopy within the preceding 10 years was associated with reduced risk for colorectal cancer on both the left and right sides. Risk reductions were greater for left-sided cancers — at 84% — than for right-sided cancers — at 56%.


The authors say their results reinforce the notion that colonoscopy reduces risks in the community setting as well as in the "highly standardized conditions" of tertiary medical centers. And an editorialist says the results "offer reassurance that colonoscopy can provide substantial protection" against both right- and left-sided disease.