Sessile serrated polyp prevalence determined by a colonoscopist with a high lesion detection rate and an experienced pathologist

Background: The prevalence of sessile serrated adenomas and/or polyps (SSA/Ps) is uncertain. Objective: To determine the prevalence of SSA/Ps and SSA/Ps with cytologic dysplasia (SSA/P-CD) by using a colonoscopist with a high lesion detection rate and an expert in serrated lesion pathology. Design: Retrospective screening colonoscopy study. Setting: Academic endoscopy unit. Patients: A total of 1910 average risk, asymptomatic patients aged >= 50 years underwent screening colonoscopy between August 2005 and April 2012 by a single colonoscopist with a high lesion detection rate. Interventions: Slides of all lesions in the serrated class proximal to the sigmoid colon and all rectal and sigmoid colon serrated lesions >5 mm in size were reviewed by an experienced GI pathologist. Main Outcome Measurements: Prevalence of SSA/Ps, defined as the proportion of patients with >= 1 SSA/P. Results: There were 1910 patients, of whom 389 had 656 lesions in the serrated class. Review by the experienced GI pathologist determined a prevalence of SSA/Ps without cytologic dysplasia of 7.4% and SSA/Ps-CD of 0.6% (total SSA/P prevalence 8.1%). SSA/Ps and SSA/Ps-CD comprised 5.6% and 0.3%, respectively, of all resected polyps. The mean size of SSA/Ps was 7.13 mm (standard deviation [SD] 4.66), and 51 of 77 (66.2%) polyps >= 10 mm in the serrated class were SSA/Ps. Limitations: Retrospective design. Conclusion: A colonoscopist with a high lesion detection rate and an experienced pathologist identified a high prevalence (8.1%) of SSA/Ps in a screening population. SSA/Ps are more common than previously believed.