Polypectomy rate: a surrogate for adenoma detection rate varies by colon segment, gender, and endoscopist

The adenoma detection rate (ADR) is an important measure of the quality of colonoscopy; it is associated with interval colorectal cancer and varies among sexes and locations. Recommended indicators of competence for colonoscopy include minimal ADRs >25% for average-risk men and >15% for women. These ADRs are rigorous, so polypectomy detection rate (PR) has been suggested as a surrogate. Colonoscopy is less effective in the proximal colon, where interval cancers are more likely to occur. We compared ADRs and PRs in different segments of colon and between sexes.

We performed a cross-sectional review of findings from 2167 screening colonoscopies performed by 65 endoscopists on average-risk outpatients at the Cleveland Clinic, 2008-2009. We reviewed colonoscopy and pathology reports of randomly selected procedures (mean, 33 ± 16 procedures per endoscopist). We calculated PRs, ADRs, and correlation between PR and ADR for each colon segment and sex.

The mean overall PR was 42% ± 16.7%, and ADR was 25% ± 3.3%. The correlation between overall ADR and PR was strong (r = 0.80). PR of 40% in men and 30% in women correlated with the established minimum benchmark ADRs of 25% and 15% for men and women, respectively. PR was more strongly correlated with ADR in the proximal colon (r = 0.92) than the distal colon (r = 0.58). The correlation was stronger in men than in women, as well as in the entire colon (r = 0.88 vs 0.75), the proximal colon (r = 0.91 vs 0.87), and the distal colon (r = 0.75 vs 0.55). The advanced ADR was 4% and did not correlate with PR (r = 0.32).

On the basis of a review of findings from screening colonoscopies, overall PR correlates with ADR for the entire colon, but PR and ADR correlate most strongly for the proximal colon, where many adenomas can be missed and interval cancers develop. The correlation between PR and ADR is weaker for women than men and for distal colon. If PR is used as a surrogate for ADR, colon location and patient sex should be considered.