Minimally invasive surgery for maximally invasive tumors: pelvic exenterations for rectal cancers.

Purpose: Trials comparing minimally invasive rectal surgery have uniformly excluded T4 tumors. The present study aimed to determine the safety of minimally invasive surgery (MIS) for locally-advanced rectal cancers requiring pelvic exenterations based on benchmarked outcomes from the international PelvEx database.

Methods: Consecutive patients of T4 rectal cancers with urogenital organ invasion that underwent MIS exenterations between November 2015 and June 2022 were analyzed from a single center. A safety threshold was set at 20% for R1 resections and 40% for major complications (≥grade IIIA) for the upper limit of the 95% confidence interval (CI).

Results: The study included 124 MIS exenterations. A majority had a total pelvic exenteration (74 patients, 59.7%). Laparoscopic surgery was performed in 95 (76.6%) and 29 (23.4%) had the robotic operation. Major complications were observed in 35 patients (28.2%; 95% CI, 20.5%-37.0%). R1 resections were found pathologically in nine patients (7.3%; 95% CI, 3.4%-13.4%). The set safety thresholds were not crossed. At a median follow-up of 15 months, 44 patients (35.5%) recurred with 8.1% local recurrence rate. The 2-year overall and disease-free survivals were 85.2% and 53.7%, respectively.

Conclusion: MIS exenterations for locally-advanced rectal cancers demonstrated acceptable morbidity and safety in term of R0 resections at experienced centers. Longer follow-up is required to demonstrate cancer survival outcomes.