Importance of Resection Margins in the Treatment of Rectal Adenomas by Transanal Endoscopic Surgery

Background Polypectomy is the gold standard for treating colorectal adenomas up to 2 cm in size. For larger lesions, various procedures ranging from endoscopy to transanal surgery can be performed and achieve varying results for en bloc resection and recurrence. There are no clear guidelines for dealing with involved resection margins. We assess the recurrence of rectal adenomas operated using TEM with full-thickness wall excision with or without free resection margins and define optimal endoscopic follow-up. Method Observational study with prospective data collection, including patients undergoing TEM between 6/2004 and 11/2017, with definitive diagnosis of rectal adenoma. Data on epidemiological, preoperative, surgical, postoperative, pathological, and follow-up variables were recorded. Univariate analysis, follow-up risk function, and multivariate logistic regression analysis were performed to detect risk factors for recurrence. Results TEM was indicated in 736 patients; 481 adenomas were identified in the preoperative biopsy, of which 95 were infiltrating adenocarcinomas (19.8%) in the definitive pathology study. With a minimum follow-up of 1 year, 372 patients were included. Pathology study showed free margins in 324 (87%). Recurrences were recorded in 15 patients (4%), up to 18 months in the free margins group and up to 24 months in the involved margins group. Thirteen patients with recurrence (86.6%) were treated with TEM. No predictors of recurrence were found in the multivariate analysis. Conclusion TEM is the technique of choice for treating rectal adenomas and recurrences, achieving a low relapse rate. Follow-up must be adapted to resection margins and should be extended to 24 months.