Comparison of laparoscopic versus robot-assisted sugery for rectal cancer after neo-adjuvant therapy: a large volume single center experience.

Purpose: This study aims to assess the short- and long-term outcomes of rectal cancer patients undergoing robotic versus laparoscopic surgery after receiving neo-adjuvant therapy. There is a lack of clarity on this topic, necessitating a comprehensive comparison.

Method: Between January 2017 and December 2021, consecutive patients who underwent laparoscopic and robotic rectal resection at a major public medical center were enrolled. All participants received neo-adjuvant chemoradiotherapy (nCRT) before surgery. The primary objective of this study was to assess the sphincter preservation rate and the rate of conversion to open surgery, using propensity score matching (PSM) analysis. Secondary endpoints included 5-year disease-free survival (DFS), 5-year overall survival (OS), short-term postoperative complications, long-term oncological prognosis, and the occurrence of low anterior resection syndrome (LARS).

Result: A total of 575 patients diagnosed with rectal cancer participated in the cohort study, with 183 individuals undergoing robotic surgery and 392 undergoing laparoscopic surgery. Patients in the robotic group tended to be younger and had higher ypT, cT, and cN stages, lower tumor locations, and higher rates of extramural vascular invasion (EMVI) and circumferential resection margin (CRM) positivity. PSM resulted in 183 patients in the robotic group and 187 in the laparoscopic group. We found a higher sphincter preservation rate in robotic group compared with laparoscopic group (92.9% vs. 86.1%, P = 0.033), with no significant difference in conversion to open surgery(P > 0.05). The robotic group had a higher incidence of postoperative chylous ascites (4.9% vs. 1.1%, P = 0.029) and potentially lower sepsis occurrence (0% vs. 1.6%, P = 0.085). No significant differences were observed in long-term oncological prognosis or 5-year survival rates (P > 0.05). The median survival time for each group was 34 months. Subgroup analysis of 76 rectal cancer patients who underwent intersphincteric resection (ISR) surgery indicated that those who selected robotic surgery had higher cN and cT stages. Furthermore, no statistically significant differences were observed in short-term and long-term clinical outcomes, LARS, OS time, and DFS time between the two surgical modalities. The primary outcomes of interest, specifically the rate of sphincter preservation and the rate of conversion to open laparotomy, showed no significant differences.

Conclusion: Robotic surgery for rectal cancer, following preoperative nCRT, demonstrates comparable technical safety and oncological outcomes to laparoscopic surgery. Further comprehensive studies are needed to to confirm the potential advantages of robotic surgical interventions.