Organ-sparing transanal endoscopic microsurgery for malignant rectal tumours: long-term survival and predictors of recurrence in a 333-patient cohort

Background: Long-term outcomes and preoperative predictors after organ-sparing transanal endoscopic microsurgery (TEM) for rectal cancer remain incompletely defined. We assessed overall survival (OS), disease-free survival (DFS), and preoperative predictors. Methods: Consecutive patients undergoing TEM with organ-sparing intent for rectal adenocarcinoma between February 1993 and April 2025 were retrospectively analysed. Preoperative variables included age, sex, lesion diameter, distance from the anal verge, location, histology, and endoscopic ultrasound (EUS) uT stage. Survival was estimated by Kaplan-Meier analysis and Cox regression. Results: 333 patients were included (median age 71 years; 63.1% male), with a median follow-up of 24 months. Post-TEM management comprised surveillance (28.5%), completion radical surgery (17.1%), or (chemo)radiotherapy (44.7%). Rectal preservation was achieved in 73.3%. 88 patients died and 71 developed recurrence, including 58 local and 26 distant recurrences. On multivariable analysis, age ≥71 years (adjusted HR 2.35, 95% CI 1.38-4.00; p = 0.002) and EUS uT2-3 (adjusted HR 2.11, 95% CI 1.23-3.63; p = 0.007) independently predicted worse OS. Conclusions: Organ-sparing TEM achieved rectal preservation in nearly three-quarters of patients, although recurrence was predominantly local. Age and EUS uT stage predicted OS, supporting staging and risk-adapted escalation.