Long-term prognosis of an endoscopically treated rectal neuroendocrine tumor: 10-year experience in a single institution

Abstract

Background and aim: The endoscopic techniques for treating a small rectal neuroendocrine tumor (NET) are performed in most large centers; however, the endoscopic management of this condition is not well established. This study was designed to determine the long-term prognosis of endoscopically resected NET.

Methods: We prospectively studied patients with endoscopically treated rectal NET in Seoul St Mary's hospital, between January 2000 and June 2010. The long-term outcomes were analyzed in association with the pathological complete resection and resection procedures.

Results: Seventy-seven patients (48 men and 29 women; mean age, 52.3 years; range, 23-77 years) were included. The average NET size was 7.0±2.8 mm (range, 3-16 mm). There was no procedure-related complication. En-bloc removal was achieved for all lesions, and the rate of histological complete resection was 75.3% (58/77). Histological complete resection rates were 71.4% (10/14) by conventional endoscopic mucosal resection (EMR), 74.1% (43/58) by a two-channel EMR, and 100.0% (5/5) by endoscopic submucosal dissection (ESD). Among six patients with incomplete histological resection, two underwent additional EMR, two underwent transanal endoscopic microsurgery, and two underwent low anterior section with lymph node dissection. The remaining 13 patients with 'possible' remnant NET underwent regular endoscopic surveillance without additional resection. In the latter group, only one patient had local recurrence, detected on regular colonoscopic surveillance, after 56 months and was treated with additional EMR. All of the patients are alive and 98.7% (76/77) of the patients are free from disease during the follow-up periods.

Conclusion: Endoscopic resection is a safe and effective modality and may potentially be used for the treatment of NETs smaller than 15 mm in diameter, those confined to the submucosal layer, and those without metastasis. Local treatment was believed to be curative in cases with complete histological resection. In addition, this treatment may have an excellent prognosis in patients with 'possible' remnant NET.