Outcomes of deep mural injury after endoscopic resection: An international cohort of 3717 large non-pedunculated colorectal polyps

Abstract Background and Aims Although perforation is the most feared adverse event associated with endoscopic mucosal resection (EMR), limited data exists concerning its management. Therefore, we sought to evaluate the short- and long-term outcomes of intra-procedural deep mural injury (DMI) in an international multi-center observational cohort of large (≥ 20mm) non-pedunculated colorectal polyps (LNPCPs). Methods Consecutive patients who underwent EMR for a LNPCP ≥ 20mm were evaluated. Significant DMI (S-DMI), was defined as Sydney DMI Classification type III (muscularis propria injury, target sign) or type IV/V (perforation without or with contamination, respectively). The primary outcome was successful S-DMI defect closure. Secondary outcomes included technical success (removal of all visible polypoid tissue during index EMR), surgical referral and recurrence at first surveillance colonscopy (SC1). Results Between July 2008 to May 2020, 3717 LNPCPs underwent EMR. Median lesion size was 35mm (interquartile range (IQR) 25 to 45mm). Significant DMI was identified in 101 cases (2.7%), with successful defect closure in 98 (97.0%) using a median of 4 through-the-scope clips (TTSCs; IQR 3 to 6 TTSCs). 3 (3.0%) patients underwent S-DMI-related urgent surgery. Technical success was achieved in 94 (93.1%) patients, with 46 (45.5%) admitted to hospital (median duration 1 day; IQR 1 to 2 days). Comparing LNPCPs with and without S-DMI, no differences in technical success (94 (93.1%) vs. 3316 (91.7%) p = 0.62) or SC1 recurrence (12 (20.0%) vs. 363 (13.6%); p = 0.15) were identified. Conclusion Significant DMI is readily managed endoscopically and does not appear to affect technical success or recurrence.