Outcomes after endoscopic mucosal resection of highly complex colorectal polyps

Aims The primary objective of this study was to evaluate the outcomes of endoscopic mucosal resection (EMR) for highly complex colorectal polyps, with a focus on technical success, adverse events, and endoscopic recurrence.

Methods This was a single-center, retrospective observational study conducted at a tertiary hospital between 2020 and 2024. Patients with highly complex polyps defined as fulfilling the SMSA 4 score (SMSA>12 points) who underwent EMR, were included. Technical success was defined as complete macroscopic resection. Intraprocedural events included significant bleeding requiring endoscopic control and was treated with snare-tip soft coagulation, and deep mural injury (DMI) was defined according to the Sydney classification (type III/IV). Recurrence was defined as the endoscopic appearance of recurrent neoplasia (confirmed histologically) at the scar site, evaluated at 6 months (SC1) and 12 months (SC2). Clinically significant post-endoscopic bleeding, such as prolonged hospital admission, blood transfusion, or the need for additional procedures, was also analyzed.

Results A total of 158 lesions in 147 patients (mean age 69.6±12.0 years; 45.6% women) classified as SMSA 4 were included. Fourteen endoscopists were involved in the procedures. 44.9% of lesions were larger than 40 mm; 96.2% were sessile or flat; 77.2% were located in the right colon; 67.7% had difficult access; 6.3% arose on a scar; and 13.9% on a difficult location (ileocecal valve, anal verge, or appendix). Histological findings showed adenomas in 63.9%, serrated lesions in 22.8%, and adenocarcinomas in 12%. Technical success on the first attempt was achieved in 144/158 lesions (91.1%). Intraprocedural bleeding occurred in 16 of 158 lesions (10.1%), and deep mural injury in 2/158 lesions (1.3%). Clinically significant post-procedural bleeding occurred in 8/147 patients (5.4%). No late perforations or deaths were reported. Among the 118 lesions that underwent follow-up at SC1, 27 (22.9%) showed recurrence. Among the 70 lesions that underwent follow-up at SC2, 8 (11.4%) showed recurrence. All recurrences, except for one, were treated endoscopically. Finally, 3(2%) patients required surgery due to technical issues.

Conclusions Endoscopic mucosal resection is an effective and safe technique for treating SMSA 4 colorectal polyps when performed by experienced endoscopists. Ongoing surveillance is essential to ensure proper management of these lesions.