Quality of Local Excision for Rectal Neoplasms Using Transanal Endoscopic Microsurgery Versus Transanal Minimally Invasive Surgery: A Multi-institutional Matched Analysis.

Background: There are no data comparing the quality of local excision of rectal neoplasms using transanal endoscopic microsurgery and transanal minimally invasive surgery.

Objective: The purpose of this study was to compare the incidence of tumor fragmentation and positive margins for patients undergoing local excision of benign and malignant rectal neoplasms using transanal endoscopic microsurgery versus transanal minimally invasive surgery.

Design: This was a multi-institutional cohort study using coarsened exact matching.

Settings: The study was conducted at high-volume tertiary institutions with specialist colorectal surgeons.

Patients: Patients undergoing full-thickness local excision for benign and malignant rectal neoplasms were included.

Interventions: Transanal endoscopic microsurgery and transanal minimally invasive surgery were the included interventions.

Main Outcome Measures: The incidence of poor quality excision (composite measure including tumor fragmentation and/or positive resection margin) was measured.

Results: The matched cohort consisted of 428 patients (247 with transanal endoscopic microsurgery and 181 with transanal minimally invasive surgery). Transanal minimally invasive surgery was associated with shorter operative time and length of stay. Poor quality excision was similar (8% vs 11%; p = 0.233). There were also no differences in peritoneal violation (3% vs 3%; p = 0.965) and postoperative complications (11% vs 9%; p = 0.477). Cumulative 5-year disease-free survival for patients undergoing transanal endoscopic microsurgery was 80% compared with 78% for patients undergoing transanal minimally invasive surgery (log rank p = 0.824). The incidence of local recurrence for patients with malignancy who did not undergo immediate salvage surgery was 7% (8/117) for transanal endoscopic microsurgery and 7% (7/94) for transanal minimally invasive surgery (p = 0.864).

Limitations: All of the procedures were also performed at high-volume referral centers by specialist colorectal surgeons with slightly differing perioperative practices and different time periods.

Conclusions: High-quality local excision for benign and rectal neoplasms can be equally achieved using transanal endoscopic microsurgery or transanal minimally invasive surgery. The choice of operating platform for local excisions of rectal neoplasms should be based on surgeon preference, availability, and cost. See Video Abstract at http://links.lww.com/DCR/A382.