A multi-institutional analysis of 263 hilar tumors during robot-assisted partial nephrectomy

Hilar tumors pose unique challenges during partial nephrectomy. We present the characteristics and outcomes of 263 patients with hilar tumors undergoing robot-assisted partial nephrectomy (RPN) in the largest series to date. Perioperative, pathologic, functional, and oncological outcomes were compared between 1467 (84.8%) patients with a non-hilar tumor and 263 (15.2%) patients with a hilar tumor undergoing RPN. Variables were compared in univariable (unadjusted) analysis and using multivariable linear, logistic, poisson, cox proportional hazards and linear mixed effects regression models adjusting for tumor diameter and RENAL Nephrometry score. Hilar tumors were larger (3.7 vs. 3.0 cm, p < 0.001) and more complex (RENAL Score 9 vs. 7, p < 0.001), leading to longer operative time (186 vs. 161 min, p < 0.001), ischemia time (18 vs. 15, p < 0.001), greater blood loss (150 vs. 100 ml, p < 0.001), eGFR decline at discharge (∆ = 3.9%, p = 0.035) and eGFR decline per month up to 36 months post-RPN (β = − 0.25; p = 0.017). In multivariable analysis, hilar tumors were only associated with a 10% increase in operative time (p ≤ 0.001) and marginally worse eGFR decline over time (β = − 0.19, p = 0.076), with no differences in other outcomes analyzed including ischemia time, blood loss, complication rate, recurrence-free survival, or eGFR decline at discharge. Although hilar tumors were found to be larger and more anatomically complex, there were only marginal differences in outcome when compared to non-hilar tumors. A hilar renal tumor should be considered for partial nephrectomy when feasible without an expected increase in complications or adverse events.