HealthDay News — Participants with an advanced adenoma at diagnostic colonoscopy have increased risk of developing colorectal cancer (CRC) relative to those with no adenoma, according to a study published in the May 15 issue of the Journal of the American Medical Association.

Benjamin Click, MD, from the University of Pittsburgh, and colleagues conducted a multicenter, prospective cohort study involving participants in the Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer randomized clinical trial of flexible sigmoidoscopy (FSG). Data were included for 154,900 men and women enrolled in PLCO, of whom 15,935 underwent colonoscopy after their first positive FSG screening result. 

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The researchers found that on initial colonoscopy, 18.1, 31.8, and 50.1% of participants had an advanced adenoma, a non-advanced adenoma, and no adenoma, respectively; the median follow-up for CRC incidence was 12.9 years. Per 10,000 person-years of observation, the incidence rates of CRC were 20, 9.1, and 7.5 for advanced adenoma, non-advanced adenoma, and no adenoma, respectively. Compared to participants with no adenoma, those with advanced adenoma were significantly more likely to develop CRC (rate ratio, 2.7; 95% confidence interval, 1.9 to 3.7; P<.001). No significant difference in CRC risk was seen for participants with non-advanced adenoma versus those with no adenoma (rate ratio, 1.2; 95% CI, 0.8 to 1.7; P=.3).

“Identification of non-advanced adenoma may not be associated with increased colorectal cancer risk,” the authors write.

One author disclosed financial ties to Medtronic.

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