Low rate of advanced adenoma formation during a 5-year colonoscopy surveillance period after adequate polypectomy of non-advanced adenoma.

Abstract

Patients with non-advanced adenoma (NAA) underwent surveillance colonoscopy at intervals shorter than the interval recommended by the guidelines. We aimed to assess the incidence of recurrent advanced adenoma (AA) over a 5-year period and to identify risk factors for recurrence. Patients with and without NAA identified at baseline colonoscopy who had had at least two colonoscopy examinations during the subsequent 5 years were included in the study. Data on the patients' demographics and colorectal findings were extracted from a specially designed colonoscopy database. The primary outcome was the finding of recurrent AA formation. Multivariate analysis was used to identify factors that predict subsequent AA formation at surveillance colonoscopy. Among 43 155 colonoscopy procedures, 828 cases were identified with NAA (374) and without an adenoma (454). Forty-eight (51.1%) of 94 received a follow-up colonoscopy within 1 year due to an inadequate baseline colonoscopy. Patients with NAA at baseline had a low incidence of AA at an interval of 1-5 years which was not statistically different from patients without adenoma formation at the initial baseline colonoscopy (1.5% vs 2.2%, P = 0.51). The incidence of AA at follow-up colonoscopy performed at 1-3 years and 3-5 years in patients with a baseline NAA was 1.7% and 1.4% (P = 0.59). Age over 50 years and male gender were independent risk factors for AA recurrence within 5 years. Surveillance colonoscopy within 5 years is of little benefit to patients who had an adequate polypectomy of an NAA at baseline. Too frequent reexamination due to concerns about AA recurrence should be avoided.