Background and aim: Repeat colonoscopy is often performed within a short time after polypectomy due to the fear that colorectal adenomas were missed during the initial colonoscopy or that new adenomas have developed. The aim of this study was to estimate the actual recurrence rate of adenoma and its association with the length of the surveillance interval after polypectomy in a southern Chinese population.
Methods: A total of 1,356 patients undergoing endoscopic polypectomy and completing three or more surveillence colonoscopies between 1976 and 2007 were retrospectively analyzed. The recurrence rates of adenoma and advanced adenoma and surveillance intervals after polypectomy were identified based on the features of adenomas detected on initial colonoscopy.
Results: The recurrence rates of advanced adenoma in patients with non-advanced adenoma on the initial colonoscopy were 0.9, 3.9, 5.8, and 29.2% during surveillance intervals of 1-3, 3-5, 5-10, and 10-20 years post-initial colonoscopy; for patients with advanced adenoma on the initial colonoscopy, the recurrence rates were 3.8, 13.1, 34.7, and 52.0% during the same surveillance intervals, respectively. Older age (p < 0.05 for trend) and male sex [hazard ratio (HR) 2.11, 95% confidence interval (CI) 1.27-3.53] were significantly associated with recurrence for advanced adenoma, as were the size and number of baseline adenoma (p < 0.05 for trend), tubulovillous, villous adenoma (HR 2.57, 95% CI 1.24-5.32), and high-grade dysplasia (HR 1.61, 95% CI 1.07-2.42). When 5% of patients had recurring advanced adenoma, the surveillance interval was estimated to be 6.9 (95% CI 6.3-12.2) years in the low-risk group and 3.0 (95% CI 2.7-3.2) years in the high-risk group.
Conclusions: Among our patient group, the recurrence of advanced adenoma after polypectomy increased with the length of the surveillance interval. Based on our results, a 3-year follow-up of patients after polypectomy could be effective in preventing the recurrence of advanced adenoma in high-risk patients.