A Systematic Review of Outcomes after Transanal Mesorectal Resection for Rectal Cancer

BACKGROUND: Transanal mesorectal resection has been developed to facilitate minimally invasive proctectomy for rectal cancer. OBJECTIVE: The purpose of this study was to evaluate the evidence regarding technical parameters, oncological outcomes, morbidity, and mortality after transanal mesorectal resection. DATA SOURCES: The Cochrane Library, PubMed, and MEDLINE databases were reviewed. STUDY SELECTION: Systematic review of the literature from January 2005 to September 2015 was used for study selection. INTERVENTION: Intervention included transanal mesorectal resection for rectal cancer. MAIN OUTCOME MEASURES: Technical parameters, histological outcomes, morbidity, and mortality were the outcomes measured. RESULTS: Fifteen predominately retrospective studies involving 449 patients were included (mean age, 64.3 years; 64.1% men). Different platforms were used. The operative mortality rate was 0.4% and the cumulative morbidity rate 35.5%. Circumferential resection margins were clear in 98%, and the resected mesorectum was grade III in 87% of patients. Median follow-up was 14.7 months. There were 4 local recurrences (1.5%) and 12 patients (5.6%) with metastatic disease. No study followed patients long enough to report on 5-year overall and disease-free survival rates. Functional outcome was only reported in 3 studies. LIMITATIONS: A low number of procedures were performed by expert early adopters. There are no comparative or randomized data included in this study and inconsistent reporting of outcome variables. CONCLUSIONS: Transanal mesorectal resection for rectal cancer may enhance negative circumferential margin rates with a reasonable safety profile. Contemporary randomized, controlled studies are required before there can be universal recommendation.