Optimal endoscopic resection method based on vertical margin distance for small rectal neuroendocrine tumors: Propensity score-matched study.

Background and study aims: Advanced endoscopic resection methods are recommended for removing rectal neuroendocrine tumors (NETs) < 10 mm, but there is no consensus on optimal endoscopic technique. This study aimed to determine whether endoscopic mucosal resection with ligation (EMR-L) is superior to endoscopic submucosal dissection (ESD) in terms of efficacy and safety, focusing on achieving adequate vertical margin distance.

Patients and methods: This dual-center cohort study included consecutive patients with rectal NETs ≤ 10 mm. Adequate vertical margins were exploratively defined as a margin distance exceeding 115 μm, the 25th percentile threshold. Propensity score matching (PSM) was applied to compare outcomes between EMR-L and ESD.

Results: The study included 204 rectal NETs from 186 patients, with 61 lesions in each group after PSM. Compared with ESD, the EMR-L group demonstrated a higher R0 resection rate (98.4% vs. 83.6%, P = 0.021), a greater proportion of adequate vertical margins (80.3% vs. 62.3%, P = 0.030), and a lower rate of positive vertical margins (1.6% vs. 13.1%, P = 0.041). Subgroup analysis indicated that lesions ≤ 5 mm without prior biopsy or central depression derived greater benefit from EMR-L. Furthermore, EMR-L was associated with significantly shorter procedure times (median 5.0 vs. 19 minutes) and a markedly lower overall complication rate (8.2% vs. 29.5%, P = 0.005), particularly perforation (3.3% vs. 16.4%, P = 0.028).

Conclusions: EMR-L outperforms ESD for small rectal NETs by achieving higher R0 and better vertical margins in shorter times, while minimizing risk of perforation.