Long-Term Outcomes Following Endoscopic Resection of Rectal Neuroendocrine Tumors

Abstract

Introduction: Colonoscopy enables the diagnosis of rectal neuroendocrine tumors (NETs) at an early stage. Rectal NETs measuring less than 10 mm in diameter and confined to the submucosal layer are currently treated with endoscopic resection (ER) techniques, such as endoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD), due to the negligible risk of lymph node and distant metastasis. However, long-term outcomes following ER are yet to be evaluated. Therefore, we retrospectively evaluated the efficacy, safety, and long-term outcomes after ER of rectal NETs. Methods: We included 75 patients (48 males, 27 females, age range: 31-81 years) in our study, and they were treated using ER (EMR; 19 cases, ESD; 56 cases) from October 2003 to March 2015. All tumors were limited to the submucosal layer on endosonography and diagnosed as NETs based on pathological analysis of preoperative biopsies, according to the World Health Organization (WHO) classifications. Follow-up colonoscopy and computed tomography were performed every year following ESD.We retrospectively evaluated tumor size, en bloc resection rates and pathological free margin resection, lymphovascular invasion, complications of bleeding and perforation, and recurrence following ER. Informed written consent was obtained from all the patients. Results: Long term outcomes following ER are presented in Table 1. Totally, 65 tumors were histopathologically diagnosed as grade 1 NETs after analysis of the resected specimens. Although lymphovascular invasion was identified in 5 cases (7%) and the pathological margins were positive in 3 cases (4%), additional surgery was not performed in these cases because of the patients' request. Postoperative bleeding occurred in 2 cases (2%), which were successfully managed by endoscopic clipping. No recurrence was observed during the median follow-up period of 25 months (range, 1-94).Table 1: resultsConclusion: ER is an effective treatment for rectal NETs and is associated with favorable long-term outcomes. Results: