Circumferential submucosal incision prior to endoscopic mucosal resection provides comparable clinical outcomes to submucosal dissection for well-differentiated neuroendocrine tumors of the rectum

Background: Small rectal neuroendocrine tumors (NETs) can be treated with endoscopic resection. Endoscopic submucosal dissection (ESD) has been accepted as a reliable technique, but it is difficult. We evaluated the feasibility and efficacy of precut and endoscopic mucosal resection (CSI-EMR) for rectal NETs compared to ESD. Methods: Patients with rectal NETs were enrolled consecutively. ESD or CSI-EMR was performed at operator’s discretion. Histological and clinical outcomes were measured and compared between the two treatment modalities. Results: Thirty-three patients were enrolled in the study. Seventeen NETs were treated by the ESD method and 16 were treated by CSI-EMR. Both groups had similar mean tumor diameters (ESD 7.53 ± 1.94 vs. CSI-EMR 6.63 ± 1.99 mm; p = 0.197). En bloc resection was achieved in 100 % of ESD group and 87.5 % of CSI-EMR group. Lateral margin involvement occurred in one patient in ESD group and two in CSI-EMR group. The histologically complete resection rate was 88.2 % (15 of 17) in the ESD group and 81.2 % (13 of 16) in CSI-EMR group (p = 0.592). One case of perforation occurred in both groups. Delayed bleeding did not occur. None of the measured outcomes were different between the two groups. Operating time was significant shorter in CSI-EMR group than in ESD group (9.69 vs. 20.12 min, respectively; p value = 0.004). Conclusions: CSI-EMR results in reliable clinical outcomes for small rectal NETs comparable to those of ESD. CSI-EMR is technically feasible and more time saving.