Transanal vs Laparoscopic and Robotic Total Mesorectal Excision for Mid-to-low Rectal Cancer: A Systematic Review of Oncological Functional and Postoperative Outcomes.

Aims and background: Minimally invasive approaches to rectal cancer surgery, including transanal, robotic, and laparoscopic total mesorectal excision (L-TME), continue to evolve. Comparative evidence regarding their efficacy and safety remains limited. This study compared oncological, functional, and postoperative outcomes of transanal vs laparoscopic and robotic TME (R-TME) for mid-to-low rectal cancer. Methods: A systematic review of randomized controlled trials (RCTs) published between 2015 and 2025 was conducted using PubMed, Medline, Cochrane, and Embase. Studies comparing transanal TME (TaTME) with laparoscopic or robotic approaches in adults with mid-to-low rectal cancer were included. Assessed outcomes included oncological, functional, and postoperative outcomes. Risk of bias was assessed using the Joanna Briggs Institute (JBI) checklist. Due to heterogeneity, findings were synthesized narratively. Results: Of 1,085 studies screened, five RCTs comparing transanal with L-TME met inclusion criteria; no trials compared transanal with robotic approaches. Oncological outcomes were comparable between groups. Transanal TME demonstrated a possible trend toward improved sexual function, although findings were limited by small sample sizes. One trial had a low risk of bias, and four had a moderate risk. Conclusion: Current randomized evidence suggests that TaTME has oncological and postoperative outcomes comparable to laparoscopic surgery in selected patients and experienced centers, although evidence of functional benefit remains limited and inconclusive. Further randomized trials comparing it with robotic approaches are warranted. Clinical significance: These findings may help clinicians counsel selected patients with mid-to-low rectal cancer regarding minimally invasive surgical options, particularly where anatomical challenges make conventional laparoscopic dissection difficult. Transanal total mesorectal excision should be considered within experienced centers with appropriate training and governance until stronger comparative evidence with R-TME becomes available.