LAUSR

BACKGROUND Transanal endoscopic surgery is an organ-sparing treatment for early-stage rectal cancer. Patients with advanced lesions are recommended for total mesorectal excision. However, some patients have prohibitive co-morbidities or refuse major surgery. OBJECTIVE To assess the cancer outcomes of patients with T2 or T3 rectal cancers who received transanal endoscopic surgery as their sole surgical treatment. DESIGN This study used a prospectively maintained database. SETTING A tertiary hospital in Canada. PATIENTS Those who underwent transanal endoscopic surgery for pathology-confirmed T2 or T3 rectal adenocarcinomas from 2007-2020. Excluded those whose surgery was performed for cancer recurrence or subsequently underwent radical resection. MAIN OUTCOME MEASURES Disease-free survival and overall survival, stratified by tumor stage and reason for transanal endoscopic surgery. RESULTS 132 patients (T2, n = 96; T3, n = 36) were included. Average follow-up was 22 months (SD±23.4). 104 patients had significant co-morbidities, while 28 refused oncologic resection. Fifteen patients (11.4%) had disease recurrence (4 local, 11 metastatic). Three-year disease-free survival for T2 tumors was 86.5% (95%CI:77.1-95.9) and 67.9% (95%CI:46.3-89.5) for T3 tumors. Mean disease-free survival was longer for T2 cancers (75.0 months, 95%CI:67.8-82.1) compared to T3 cancers (50 months, 95%CI:37.7-62.3, p = 0.037). Three-year disease-free survival for patients who declined total mesorectal excision was 84.0% (95%CI:67.1-100) whereas patients too medically comorbid for surgery had a three-year disease-free survival of 80.7% (95%CI:69.7-91.7). Three-year overall survival was 84.9% (95%CI:73.9-95.9) for T2 tumors and 49.0% (95%CI:26.7-71.3) for T3 tumors. Patients who declined radical resection had similar three-year overall survival (89.7%, 95%CI:76.2-100), compared to patients who were unable to undergo total mesorectal excision due to medical comorbidities (98.1%, 95%CI:95.6-100). LIMITATIONS Small sample, single institution, surgeon experience. CONCLUSIONS Oncologic outcomes are compromised in patients treated by transanal endoscopic surgery for T2 and T3 rectal cancer. However, transanal endoscopic surgery remains an option for informed patients who prefer to avoid radical resection.