Completion Surgery in Unfavorable Rectal Cancer after Transanal Endoscopic Microsurgery: Does It Achieve Satisfactory Sphincter Preservation, Quality of Total Mesorectal Excision Specimen, and Long-term Oncological Outcomes?

Abstract

BACKGROUND: Unfavorable adenocarcinoma after transanal endoscopic microsurgery requires "completion surgery"with total mesorectal excision. The literature on this procedure is very limited. OBJECTIVE: This study aims to assess the percentage of transanal endoscopic microsurgery that will require completion surgery. DESIGN: This is an observational study with prospective data collection and retrospective analysis from patients who were operated on consecutively. SETTINGS: The study was conducted at a single academic institution. PATIENTS: Patients undergoing transanal endoscopic microsurgery from June 2004 to December 2018 who later required total mesorectal excision were included. MAIN OUTCOME MEASURES: All the patients followed the same protocol: preoperative study, indication of transanal endoscopic microsurgery with curative intent, performance of transanal endoscopic microsurgery, and completion surgery indication 3 to 4 weeks after transanal endoscopic microsurgery. RESULTS: Seven hundred seventy-four patients underwent transanal endoscopic microsurgery, 622 with curative intent (group I: adenoma, 517; group II: adenocarcinoma, 105). Completion surgery was indicated in 64 of 622 (10.3%) patients: group I, 40 of 517 (7.7%) and group II, 24 of 105 (22.9%). After applying exclusion criteria, completion surgery was performed in 55 patients (8.8%). Abdominoperineal resection was performed in 23 (45.1%); the initial lesion was within 6 cm of the anal verge in 19 of these 23 (82.6%). The clinical morbidity rate (Clavien Dindo> II) was 3 of 51 (5.9%). Total mesorectal excision was graded as complete in 42 of 49 (85.7%). The circumferential resection margin was tumor-free in 47 of 50 (94%). Median follow-up was 58 months. Local recurrence was recorded in 2 of 51 (3.9%) and systemic recurrence was recorded in 7 of 51 (13.7%); 5-year disease-free survival was 86%. LIMITATIONS: The limitations are defined by the study's observational design and the retrospective analysis. CONCLUSION: The indication of completion surgery after transanal endoscopic microsurgery is low, but is higher in the indication of adenocarcinoma. Compared with initial total mesorectal excision, completion surgery requires a higher rate of abdominoperineal resection, but has similar postoperative morbidity, total mesorectal excision quality, and oncological results.