Outcomes of Deep Mural Injury After Endoscopic Resection: An International Cohort of 3717 Large Non-Pedunculated Colorectal Polyps.

Background & 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 (≥20 mm) non-pedunculated colorectal polyps (LNPCPs).

Methods: Consecutive patients who underwent EMR for a LNPCP ≥20 mm 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). Three (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 = .62) or SC1 recurrence (12 (20.0%) vs 363 (13.6%); P = .15) were identified.

Conclusions: Significant DMI is readily managed endoscopically and does not appear to affect technical success or recurrence.