Detection of clinically relevant serrated polyps during screening colonoscopy: results from seven cooperating centers...

Serrated polyps have been recognized as precursors of colorectal cancer (CRC) via the serrated pathway. Endoscopic detection and histopathological evaluation of serrated polyps are challenging. The aims of this study were to determine detection rates of the recently proposed entity of clinically relevant serrated polyps (crSPs) and to identify factors that influence their detection in a primary colonoscopy screening cohort.

We retrospectively analyzed average-risk screening colonoscopies performed at a tertiary academic hospital and six community-based private practices in Germany between 01/01/2012 and 14/12/2016. Exclusion criteria were age < 50 years, conditions with increased risk for CRC (e. g. inflammatory bowel disease, history of CRC, hereditary cancer syndromes), and incomplete procedures. CrSPs were defined as serrated polyps ≥ 10 mm and/or > 5 mm located proximally to the splenic flexure. Conventional adenomas were defined as adenomas excluding serrated polyps.

A total of 4161 colonoscopies from average-risk individuals were included (median age 62 years [interquartile range 56 - 69]; 48.6 % male). CrSPs were detected in 6.9 %, with a mean detection rate of 4.7 % (95 % confidence interval 2.3 % - 7.2 %). Detection rates ranged from 0 % to 16.2 %. In multivariate analysis, simultaneous detection of conventional adenomas and an endoscopist adenoma detection rate of ≥ 25 % were significantly associated with increased detection of crSPs, with odds ratios of 1.43 (95 %CI 1.11 - 1.85; P = 0.01) and 7.35 (95 %CI 4.43 - 12.19; P < 0.001). The individual endoscopist's detection rate for conventional adenomas and crSPs were significantly correlated (r = 0.54, P = 0.02).

Detection rates for crSPs differed between participating endoscopists. However, individual skills to detect polypoid lesions have a relevant bearing on the detection rate of crSPs.