Serrated Polyp Detection Predicted Interval Cancer Independent of Adenoma Detection Rate

Serrated Polyp Detection Predicted Interval Cancer Independent of Adenoma Detection Rate

Douglas K. Rex, MD, MASGE, reviewing van Toledo DEFWM, et al. Lancet Gastroenterol Hepatol 2022 May 9.

The adenoma detection rate (ADR) is currently the recommended measure of the quality of mucosal inspection during colonoscopy. ADR does not include sessile serrated lesions (SSLs) in its current definition. Across the literature, the correlation between detection of adenomas and serrated lesions is at least moderate and sometimes good. There is increasing pressure to establish a detection target for serrated lesions because of imperfect correlation with adenoma detection and because SSLs contribute disproportionately to interval cancer. 

In a Dutch study involving 239,217 colonoscopies performed by 441 endoscopists in fecal immunochemical test-positive patients, the proximal serrated polyp detection rate (PSPDR; any SSL, hyperplastic polyp [HP], or traditional serrated adenoma identified proximal to the descending colon) was 11.9%, and the median ADR was 66.3%. 

There were 305 cases of interval cancer. The postcolonoscopy colorectal cancer (PCCRC) rate dropped by 7% for each 1% increase in PSPDR. Compared with patients of the lowest quintile PSPDR performers, patients of the highest quintile PSPDR endoscopists had a 66% reduction in PCCRC.

Endoscopists were divided into groups of high and low PSPDR and high and low ADR according to median performance. Those with high PSPDR and high ADR comprised 37% of endoscopists. Compared with this group, the hazard ratio (HR) for PCCRC was 1.79 in patients of endoscopists with high ADR and low PSPDR (13% of endoscopists). The HR was 1.97 for patients of endoscopists with high PSPDR and low ADR (13% of endoscopists). For patients of doctors with low PSDPR and low ADR (37% of endoscopists), the HR was 2.55. PSPDR performed as well as the total colon sessile serrated lesion detection rate and the sessile serrated polyp detection rate.

Douglas K. Rex, MD, FASGE


These data add to growing pressure to create a separate detection target for serrated lesions. Seeing that 13% of endoscopists had a high ADR and low PSPDR gives us a sense of how many underperforming endoscopists could be identified by the added effort of measuring a serrated lesion detection target. A good aspect of PSPDR is that it gets around the problem of interobserver variation between pathologists in identifying SSLs versus HPs. In prospective use, PSPDR is inherently more corruptible than ADR because the location of serrated polyps in the colon can be easily gamed. Nevertheless, the call to incorporate serrated detection into quality measures increases.

Note to readers: At the time we reviewed this paper, its publisher noted that it was not in final form and that subsequent changes might be made.


van Toledo DEFWM, IJspeert JEG, Bossuyt PMM, et al. Serrated polyp detection and risk of interval post-colonoscopy colorectal cancer: a population-based study. Lancet Gastroenterol Hepatol 2022 May 9. (Epub ahead of print) (

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