The efficacy and safety of endoscopic resection for multiple rectal neuroendocrine tumors: a retrospective cohort study from a tertiary center

Multiple rectal neuroendocrine tumors (MR-NETs) are rare. There is no consensus on their characteristics and treatment. We aimed to evaluate the efficacy and safety of endoscopic resection (ER) for MR-NETs. We performed a retrospective review of 24 patients with 57 rectal NETs who underwent ER at Zhongshan Hospital, Fudan University. Baseline information, procedure-related characteristics and postoperative outcomes were analyzed. The mean maximal diameter was 8.2 ± 4.5 mm, with 43 lesions < 10 mm and 14 lesions ≥ 10 mm. Seventeen patients had 2 lesions, 6 patients had 3 lesions and 1 patient had 5 lesions. There were 53 lesions treated by endoscopic submucosal dissection, 2 lesions treated by endoscopic mucosal resection, and 2 lesions treated by endoscopic submucosal excavation. The en bloc resection rate and technical success rate were both 100%. There were no delayed bleeding or perforation. All patients were eventually discharged safely, with a mean post-procedure hospital stay of 1.81 ± 0.48 days. Tumor grade was G1 in 54 (94.7%) lesions and G2 in 3 lesions (5.3%). Positive margins were found in 10 lesions, including 2 lesions (3.5%) with lateral margin involvement, and 8 cases (14.0%) with basal margin involvement. Mean follow-up was 34.96 ± 23.20 months, with only 3 local recurrences which were successfully managed by salvage ER. There were no recurrences in the 10 lesions with positive margins. ER is a safe and effective technique for small MR-NETs. Positive resection margins do not appear to adversely affect the prognosis of small MR-NETs. Salvage ER may be a viable option in recurrent cases.