Clinical Implementation and Perioperative Outcomes of Robot-Assisted Pelvic Exenteration for Primary Rectal Cancer: A Multicenter Japanese Experience.

Aim: Robot-assisted pelvic exenteration (RPE) has been introduced as a minimally invasive option for selected patients; however, its clinical implementation, patient selection, and perioperative outcomes for primary rectal cancer remain unclear. This study describes the use and outcomes of RPE in a multicenter Japanese cohort. Methods: This retrospective observational secondary analysis included patients who underwent pelvic exenteration (PE) for primary rectal cancer at 26 Japanese institutions between January 2012 and October 2022. Patient characteristics, surgical indications, temporal trends in operative approach, and perioperative outcomes were summarized descriptively. Propensity score-matched analyses were performed as supplementary exploratory analyses. Results: Among 135 patients, 43 (32%) underwent RPE, 57 (42%) underwent laparoscopic PE, and 35 (26%) underwent open PE. In the RPE cohort, median operative time was 690 min, median blood loss was 360 mL, and 13 patients (30%) received intraoperative transfusion. One patient (2%) required conversion to open surgery, and RM0 resection was achieved in 42 (98%). Clavien-Dindo Grade II or higher and Grade III or higher complications within 30 days occurred in 16 (37%) and seven (16%) patients, respectively. No patient underwent reoperation during hospitalization or died within 30 days. Grade III or higher morbidity between 31 and 90 days occurred in five patients (12%). Median hospital stay was 23 days. Conclusion: RPE was performed with acceptable perioperative outcomes in selected patients with primary rectal cancer. It may serve as a complementary approach at institutions with sufficient experience in PE, whereas open surgery remains essential for extensive or technically demanding disease.