Postoperative Outcomes of Robotic Versus Conventional Surgery in a Multi-Cancer Cohort: A Retrospective Cohort Study

Background/Objectives: Evidence on robotic surgery is largely procedure-specific and depends on the comparator. We examined associations with postoperative outcomes, prioritizing colorectal and uterine cancer and distinguishing laparoscopic from open comparators. Methods: This retrospective cohort included 2139 patients undergoing elective surgery for colorectal, uterine, prostate, or renal cancer at a tertiary referral center in 2019-2023. The primary analysis included 1232 colorectal or uterine cancer patients undergoing robotic (n = 462) or laparoscopic (n = 770) surgery. Generalized linear models adjusted for age, sex, cancer type, and T category/FIGO stage group; operative time and staffing were added in sensitivity analysis. Absolute differences were estimated by G-computation. The four-cancer pooled analysis was secondary. Results: Robotic surgery was associated with a shorter hospital stay (length-of-stay ratio 0.78; 95% CI 0.73-0.83; adjusted difference 2.34 days), which persisted with operative-time/staffing and calendar-year adjustment. Rehospitalization within 30 days after surgery was higher overall (adjusted odds ratio [aOR] 1.82; 95% CI 1.34-2.47), but differed by cancer: aOR 2.50 (95% CI 1.77-3.53) for colorectal and 0.38 (95% CI 0.16-0.90) for uterine cancer (interaction p < 0.001). Estimates for 30-day mortality, postoperative complications, and surgical site infection were imprecise. Conclusions: Rehospitalization differed in direction between these cancers, indicating that cancer type and comparator selection materially affect inference. These associations do not establish a platform-specific benefit or transferable bed-day savings.