Margin marking before colorectal endoscopic mucosal resection and its impact on neoplasia recurrence (with video).

BACKGROUND AND AIMS Ablation of resection margins after endoscopic mucosal resection (EMR) of large nonpedunculated colorectal polyps decreases recurrence. Margin marking before EMR (EMR-MM) may represent an alternative method to achieve a healthy resection margin. We aimed to determine the efficacy of EMR-MM in reducing neoplasia recurrence. METHODS Single-center historical control study of EMR cases (EMR-MM vs conventional EMR) for nonpedunculated polyps ≥20 mm between 2016 to 2021. For EMR-MM, cautery marks were placed along the lateral margins of the polyp with the snare tip. EMR was then performed to include resection of the healthy mucosa containing the marks. We compared recurrence at surveillance colonoscopy after EMR-MM versus historical controls. Multivariable logistic regression was performed to identify factors associated with recurrence. RESULTS A total of 210 patients with 210 polyps (median size 30 mm; IQR: 25-40 mm) underwent EMR-MM (n=74) or conventional EMR (n=136). Patient and lesion characteristics were similar between the groups. At a median follow-up of 6 months, the recurrence rate was lower with EMR-MM (6/74; 8%) compared with historical control (39/136; 29%) (p<.001). EMR-MM was not associated with increased rate of adverse events. On multivariable analysis, EMR-MM remained the strongest predictor of recurrence (OR, 0.20; 95% CI, 0.13-0.64; p=0.003) aside from polyp size (OR, 2.81; 95% CI, 1.35-6.01; p=0.008). CONCLUSION In this single-center historical control study, margin marking before EMR of large nonpedunculated colorectal polyps reduced recurrence risk by 80% when compared with conventional EMR. This simple technique may provide an alternative to margin ablation.