Robot-assisted partial nephrectomy for complex renal tumors: Analysis of a large multi-institutional database.

INTRODUCTION: Highly complex renal masses pose a challenge to urologic surgeons' ability to perform robotic partial nephrectomy (RPN). Given the increased utilization of the robotic approach for small renal masses, we sought to characterize the outcomes and determine the safety and feasibility of RPN for complex renal masses from our large multi-institutional cohort. METHODS: We performed a retrospective analysis of patients with R.E.N.A.L. Nephrometry Scores ≥10 who underwent RPN in our multi-institutional cohort (N = 372). Baseline demographic, clinical and tumor related characteristics were evaluated with the primary endpoint of trifecta achievement (defined as negative surgical margin, no major complications, and warm ischemia time ≤25 min). Relationships between variables were assessed using the chi-square test of independence, Fisher exact test, Mann-Whitney U test, and Kruskal Wallis test. Logistic regression was used to evaluate the relationship between baseline characteristics and trifecta achievement. RESULTS: Of 372 patients in the study, mean age was 58 years, and median BMI was 30.49 kg/m2. The median tumor size was 4.3 cm (3.0-5.9 cm). Most of the patients had R.E.N.A.L. scores of 10 (n = 253; 67.01%). Overall, trifecta was achieved in 72.04% of patients. Stratifying intraoperative and postoperative outcomes by R.E.N.A.L. scores, there was no significant difference in trifecta achievement, operative time, warm ischemia time (WIT), open conversion, major complication, or positive margin rates. Length of hospital stay was significantly longer for higher R.E.N.A.L. scores (median days 2 vs. 1, P = 0.012). Multivariate analyses for factors associated with trifecta achievement concluded that age and baseline eGFR were independently associated with trifecta achievement. CONCLUSION: RPN is a safe and reproducible procedure for complex tumors with R.E.N.A.L. Nephrometry scores ≥10. Our results suggest excellent rates of trifecta achievement and short-term functional outcomes when performed by experienced surgeons. Long-term oncological and functional evaluation are needed to further support this conclusion.