The Long-Term Risk of Metachronous Advanced Adenoma Recurrence After Endoscopic Submucosal Dissection for Colorectal Neoplasia: A Propensity-Score Matched Longitudinal Cohort With 5-Year Follow-Up.

Introduction: Long-term data on metachronous advanced adenoma (AA) recurrence after endoscopic submucosal dissection (ESD) remain scarce, leading to a lack of a standardized surveillance strategy. This study aims to evaluate the long-term risk of recurrent AA after ESD.

Materials and methods: A longitudinal retrospective cohort study with propensity-score matching was conducted in a tertiary hospital in Hong Kong. Subjects who underwent colorectal ESD between 2011 and 2017 were enrolled and defined as the post-ESD group. Selected subjects who underwent polypectomy in their index colonoscopy between 2011 and 2017 were enrolled and stratified into the low- intermediate- and the high-risk groups according to the US Multi-Society Task Force (USMSTF) guideline. The risks of recurrent AA were assessed by Cox proportional hazards regression in the matched cohorts.

Results: A total of 1745 subjects were included, with 203 post-ESD subjects fully matched with 729 high-risk and 813 low-intermediate-risk subjects, respectively. The 5-year cumulative incidence of recurrent AA in the post-ESD group was 7.8%. After 5 years, the post-ESD group was not associated with a higher rate of recurrent AA to the low-intermediate-risk group (7.8% vs. 5.5%; adjusted HR [aHR] 1.64, 95% CI 0.77-3.48, p = 0.197) but a lower rate of recurrent AA (7.8% vs. 11.8%; aHR 0.40, 95% CI 0.19-0.85, p = 0.017) than the high-risk group.

Conclusion: Subjects who underwent ESD were not associated with an increased 5-year risk of metachronous AA recurrence than low-intermediate or high-risk groups in USMSTF. The findings will inform future guidelines on post-ESD surveillance colonoscopy strategies.