Prevalence of serrated polyps and association with synchronous advanced neoplasia in screening colonoscopy.

Background and study aims: Serrated polyps of the large intestine comprise a heterogeneous group of lesions with distinct histological and malignant features. The aim of the study was to estimate the prevalence of serrated polyp subtypes in a cohort of individuals undergoing screening colonoscopy, and to identify associations between the detection of serrated polyp subtypes and advanced neoplasia. Patients and methods: Data on serrated polyps, adenomas, and cancers were collected from participants of a randomized screening trial that compared colonoscopy with computed tomography colonography. Only data from participants in the colonoscopy arm were used. Logistic regression analyses were performed to identify associations between patients' age, sex, and prevalence of the different types of serrated polyps and to identify associations between the detection of these polyps and advanced neoplasia (defined as an adenoma >= 10mm, villous component, high grade dysplasia or colorectal cancer). Results: A total of 1426 screen-naive individuals (51% male) with a median age of 60 years (IQR 55-65) were included. The prevalence of hyperplastic polyps, sessile serrated adenomas/polyps (SSA/Ps), and traditional serrated adenomas (TSAs) was 23.8 %, 4.8 %, and 0.1 %, respectively. SSA/Ps comprised 7.3% of all polyps. No differences based on age or sex were observed in the prevalence of SSA/Ps. Proximal and large (>= 10 mm) hyperplastic polyps, as well as proximal and large (>= 10mm) SSA/Ps, were associated with synchronous advanced neoplasia. Conclusions: Serrated polyps, including SSA/Ps, were frequently encountered in routine screening colonoscopies. Large and proximal hyperplastic polyps, as well large and proximal SSA/Ps, were associated with advanced neoplasia.