Risk of metachronous polyps in individuals with serrated polyps

BACKGROUND: Surveillance colonoscopy is recommended for patients with serrated polyps, but the risk of metachronous polyps is not well established. OBJECTIVE: The aim of this study was to determine the risk of metachronous polyps in patients with serrated polyps and assess the relationship of coexistent adenomas in polyp recurrence. DESIGN AND SETTING: This prospective cohort study was conducted in a single tertiary center in the United States. PATIENTS: Patients were included if they had a hyperplastic polyp ≥10 mm a sessile serrated polyp or a traditional serrated adenoma with or without coexistent adenomas, or only adenomas at baseline colonoscopy MAIN OUTCOME MEASUREMENTS: The cumulative incidence of advanced adenomas and advanced serrated polyps was the primary outcome measured. RESULTS: The incidence of metachronous advanced adenomas was highest in patients with baseline advanced adenoma (40%) and 10% in those with serrated polyps only. The coexistence of serrated polyps and adenomas did not increase the risk of metachronous advanced adenoma (27% in serrated polyps + advanced adenoma and 7% in serrated polyps + nonadvanced adenoma). Metachronous serrated polyps ≥10 mm were seen exclusively in patients with baseline serrated polyps (serrated polyps only, 7%; serrated polyps + nonadvanced adenoma, 11%; serrated polyps +advanced adenoma, 9%) and not in patients with only adenomas at baseline. LIMITATION: The small cohort and the data collected retrospectively were limitations of this study. CONCLUSIONS: Patients with baseline large hyperplastic polyps, sessile serrated polyps with or without dysplasia, or traditional serrated adenoma have a low risk of metachronous advanced adenoma, but were the sole group with recurrent large serrated polyps. No effect of coexistent serrated polyps and adenomas was seen for the recurrence of advanced adenoma.