IDDF2021-ABS-0025 Discriminating endoscopic features of sessile serrated lesions: a systematic review and meta-analysis

Sessile serrated lesion(SSL) is notorious for its malignancy potential and the difficulty to be detected and distinguished under endoscopy. This systematic review and meta-analysis aimed to evaluate endoscopic characteristics of SSL and delineate features that inform distinction between SSA/P and other types of lesions, including hyperplastic polyp (HP) and conventional adenoma. MEDLINE, Embase and Cochrane Library from the inception to September 9, 2020, were searched for cohort, cross-sectional or case-control studies comparing endoscopic characteristics of SSL and other polyps. The primary outcome measure was the odds of finding specific endoscopic characteristics in patients with SSL compared with other types of polys in patients undergoing colorectal cancer screening. We included 74 studies from 16 countries comprising 34,535 SSL. Compared with HP, SSL was more likely to be in the right colon (OR 5.45; 95% CI 4.13-7.17; P<0.01); larger in size (>5mm vs. <=5mm OR 5.60; 95% CI 3.82-8.22; P<0.01); in Paris-0-II morphology (OR 2.33; 95%CI 1.45-3.70; P<0.01); having mucus cap (OR 8.48; 95% CI 4.86-14.8; P<0.01); vague margin under white light endoscopy (OR 2.71; 95% CI 1.88-3.92; P<0.01); having expended crypt opening (OR 5.09; 95% CI 1.87-13.9; P<0.01), varicose microvascular vessels (OR 6.17; 95% CI 1.57-24.3; P<0.01) and thick branched vessel (OR 5.17; 95% CI 1.81-15.8; P<0.01) under magnified narrow band imaging and type II-O pit pattern (OR 18.56; 95% CI 8.45-40.7; P<0.01) under magnified chromoendoscopy. We systematically synthesised current evidence on the discriminating endoscopic features of SSL. These findings could enhance the detection of SSL in endoscopy practice.