Clinical Outcome in Colonic Neuroendocrine Neoplasms

Abstract

Introduction: Colonic Neuroendocrine Neoplasms (NEN) is classified of Neuroendocrine Tumor (NET) G1, NET G2, Neuroendocrine Carcinoma (NEC) in according with the 2010 WHO Classification. Herein we report the clinical outcome of colonic NEN. Methods: 52 patients treated in our hospital between 2004 and 2014 were reviewed, which were defined pathologically as colonic NEN. Results: The mean follow-up time was 37 months. 36 patients were male and 16 patients were female. Median age of 52 patients were 61.2 years (30-85 years). 46 tumors (88.5%) were NET. The tumor localization of NET is lower rectum: upper rectum: recto-sigmoid = 40:5:1. 98% of NET (n=45) were diagnosed stage I. 28 cases were underwent endoscopic resection. The mean tumor size was 5.8mm (2-11mm) in these cases, and had no recurrence. In other cases, transanal partial excision, transsacral partial excision or rectum excision with regional lymph node dissection were performed. Liver metastases and local recurrence were identified in 1 case at Stage I after surgery. Without this 1 case, no recurrences were not identified. 6 tumors (11.5%) were NEC including 5 MANEC (Mixed Adenoneuroendocrine Caricinoma). Tumors were located at the cecum, ascending colon and transverse colon. The mean tumor size was 58.3mm (25-80mm). Right hemicolectomy with regional lymph node dissection was performed in all cases. These were diagnosed at stage IIb (n=2), stage IIIb (n=2) and stage IV (n=2). Two cases had recurrence and were administered chemotherapy. However, because of limited therapeutic effect the disease progressed. Conclusion: In colonic NET G1 and G2, which located mostly in rectum, and good overall survival is expected by resection. In tumor size≤10mm cases, endoscopic resection can be useful. In tumor size>10mm and lower rectum location cases, careful selection of operation such as transanal partial excision or rectum excision is needed from the perspective for conservating anus. In colonic NEC, the most frequent location is ascending colon and these have highly malignancy. When these are diagnosed as NEC, the disease already progress and its prognosis is poor. It is difficult to treat colonic NEC by only surgical resection. No effective chemotherapy has been established. It is thus important to gather more evidence on this disease. The optimal strategy and strong chemotherapy for the management of NEN.