Endoscopic Submucosal Dissection or Conventional Endoscopic Mucosal Resection Is an Effective and Safe Treatment for Rectal Carcinoid Tumors: A Retrospective Study

Background: Various methods for complete endoscopic resection of rectal carcinoid tumors have been reported. The aim of the present study was to evaluate the clinical usefulness of endoscopic submucosal dissection (ESD) as a new method or conventional endoscopic mucosal resection (EMR) in order to remove rectal carcinoid tumors completely. Materials and Methods: Between April 2004 and June 2009, 12 patients with rectal carcinoid tumors, estimated at 10 mm, more or less, in diameter, without atypical features and dissected by ESD or resected by EMR, were recruited for this analysis. The complete dissection or resection rate, complications associated with the procedure, local recurrence, and distant metastases were evaluated. Results: Twelve patients were 9 males and 3 females with a mean age of 47.6 years (range, 32-64). The patients had no complaints of carcinoid syndrome symptoms. Tumor size ranged from 5 to 13mm in diameter, with an average size of 8.8 mm, and 11 of 12 patients (92.7%) had tumors of diameter less than 10 mm. Three of 12 patients (25.0%) were treated by ESD and 9 (75.0%) by conventional EMR. All lesions, including 13-mm-sized carcinoid tumors, were histologically determined to be completely dissected or resected. There were no immediate or late complications (i.e., bleeding or perforation) after ESD or conventional EMR. Histopathologically, there was no tumor invasion beyond the submucosal layer, and all were classified as classical-type carcinoids without lymphovascular invasion. Neither local recurrence nor distant metastasis were detected during a median follow-up period of 28 months. Conclusions: In this study, ESD as a new method or conventional EMR shows promise or potential as a useful, safe procedure to dissect or resect rectal carcinoid tumors of 10 mm, more or less, in diameter. However, long-term outcome remains to be elucidated by a large-scale, prospective study.