Prevalence of Proximal Serrated Polyps and Conventional Adenomas in an Asymptomatic Average-Risk Screening Population

Background/Aims: Detection of proximal serrated polyps (PSPs) is increasingly recognized as a new qualitative target for colonoscopy. The aims of this study were to assess the detected prevalence of PSPs and synchronous adenomas in an asymptomatic average-risk screening cohort and to evaluate potential factors associated with detection of PSPs. Methods: The study included 1,375 asymptomatic average-risk Korean patients (aged 50 years or older) who underwent screening colonoscopy. In total, 1,710 polyps were evaluated pathologically. Results: The overall PSP detection rate (PSPDR) was low at 3.1%, despite high polyp (54.0%) and adenoma detection rates (ADRs, 43.5%). ADR did not correlate with PSPDR, but it was strongly correlated with PDR (r=0.810; p<0.001). Patients with PSPs were more likely to have longer withdrawal time and more proximal colon adenomas than patients without PSPs (adjusted odds ratio [OR], 1.19; 95% confidence interval [CI], 1.09 to 1.31; p<0.001) (adjusted OR, 2.03; 95% CI, 1.06 to 3.88; p=0.031, respectively). Conclusions: The detected prevalence of PSPs was low (<5%) in an asymptomatic average-risk screening Korean population, despite the high prevalence of conventional adenomas. A longer mucosal inspection of the proximal colon may serve as a practical method to enhance detection of PSPs.