Delayed surveillance colonoscopy after piecemeal EMR is not associated with increased recurrence rates

Background and study aims: First surveillance colonoscopy (SC1) following piecemeal endoscopic mucosal resection (pEMR) is recommended at 3 to 6 months. We aimed to investigate whether delayed SC1 is associated with increased risk of recurrence. Patients and methods: This was a retrospective analysis of a prospective cohort of patients undergoing pEMR for large non-pedunculated colorectal polyps (LNPCPs). Patients were categorized into standard SC1 (3-6 months) and delayed SC1 (> 6 months) groups. The primary endpoint was recurrence at SC1. Secondary outcomes included recurrence at second surveillance colonoscopy (SC2) and features of lesion recurrence. Subgroup analyses of very delayed SC1 and high-risk lesions were performed. Recurrence rates were also evaluated with propensity score matching (PSM). Results: We analyzed 577 lesions (standard: 407, delayed: 170) with a median polyp size of 30 mm (interquatile range [IQR] 25-40). Median time to SC1 was 5 months (IQR 5-6) in the standard versus 9 months (IQR 7-13) in the delayed group (P < 0.01). There were no significant differences in SC1 recurrence rates between groups (6.4% versus 6.5% in the standard and delayed respectively, P = 1). At SC2, recurrence rate was also similar between groups (3.8% versus 8.8% respectively, P = 0.43). Recurrence rates did not differ significantly among the analyzed subgroups. Recurrence rates did not differ significantly among the analyzed subgroups or in the PSM analyses. No advanced recurrences were detected at SC1 or SC2. Conclusions: Delayed SC1 is not associated with increased recurrence rates. Complete resection can be anticipated for most lesions and SC1 at 1-year post resection may be sufficient.