Safety and Efficacy of Simplified EMR Versus ESD for Rectal Neuroendocrine Tumors ≤ 10 Mm: A Retrospective Cohort Study

Abstract

Background: Rectal neuroendocrine tumors (NETs) ≤ 10 mm are commonly managed by endoscopic resection. However, the optimal technique remains controversial. We aimed to compare the efficacy and safety of a simplified endoscopic mucosal resection (sEMR) technique, performed without submucosal injection, with conventional endoscopic submucosal dissection (ESD) for small rectal NETs. Methods: This retrospective, single-center study included 74 patients with histologically confirmed rectal NETs ≤ 10 mm treated with sEMR (n = 37) or ESD (n = 37) between January 2022 and January 2025. Patients in the ESD group were matched 1:1 by age and gender. Baseline characteristics, procedural outcomes, histopathologic findings, and cost were analyzed. The primary outcome was histological complete resection (R0) rate; secondary outcomes included en bloc resection, intraoperative bleeding, tumor-to-margin distance, operation time, and material costs. Results: The R0 resection rate was significantly higher in the sEMR group compared to the ESD group (91.9% vs. 67.6%; p = 0.019). Tumor-to-margin distance was also significantly greater in the sEMR group [median (IQR): 0.2 (0.1-0.3) mm vs. 0.1 (0-0.2) mm; p = 0.024]. Intraoperative bleeding was less frequent in the sEMR group (2.7% vs. 21.6%; p = 0.028). Median operation time (409 vs. 1469 s; p < 0.001) and material cost (1486 vs. 6390 CNY; p < 0.001) were both significantly lower in the sEMR group. Conclusions: Compared with ESD, the simplified EMR technique without submucosal injection demonstrated higher R0 resection rates, lower bleeding risk, shorter operation time, and lower costs for small rectal NETs. sEMR may offer a safe, efficient, and cost-effective alternative in selected patients.

Keywords: R0 resection; cost-effective; endoscopic mucosal resection; endoscopic submucosal dissection; rectal neuroendocrine tumor.

Figure 1

Process of simplified EMR. (a,b) The lesion is localized and elevated with the aid of a titanium clip placed at its base. (c,d) A snare is employed to securely capture the lesion. (e,f) The captured lesion is resected using electrocautery. (g,h) The resection surface is densely closed with titanium clips to prevent postoperative bleeding.

Figure 2

The tumor-to-margin distance was significantly greater in the sEMR group compared with the ESD group (median [IQR]: 0.2 [0.1–0.3] mm vs. 0.1 [0–0.2] mm, p = 0.024).