Outcomes of robot-assisted partial nephrectomy (RAPN) for cystic renal tumor

Cystic renal tumors (cRT) pose technical challenges during robot-assisted partial nephrectomy (RAPN) due to the risk of cyst rupture, yet their true impact on perioperative outcomes remains unclear. This study aimed to evaluate the surgical and pathological outcomes of RAPN for cRT compared with solid renal tumors (sRT).

We retrospectively analyzed 694 consecutive RAPN cases (2016-2023) at a high-volume center. Tumors were categorized as sRT (n = 609), partially cystic renal tumors with < 50% cystic component (pcRT), and cRT with ≥ 50% cystic component. Patient background, perioperative outcomes, resection techniques, and oncological results were compared. The SIB score was used as a surrogate measure for tumor resection method, distinguishing between enucleation, enucleoresection, and resection.

Among these 694 cases, 609 (88%), 36 (5%) and 49 (7%) cases were classified into sRT, pcRT and cRT groups, respectively. Age, BMI, RENAL score, or clinical stage showed no differences among the three groups, and tumor size of pcRT and cRT was significantly larger than that of sRT (P = 0.067). No significant differences were observed in operative time, warm ischemia time, blood loss, trifecta achievement, or positive surgical margins. Pathologic up-grade was noted in 28 cases (2.6%) in sRT, while none were noted in pcRT and cRT. Multivariate analysis of predictive factors for WIT, trifecta, and pentafecta, showed that cystic tumor was not identified as predictive factors.

RAPN for cystic renal tumors is safe and feasible, with perioperative, pathological, and functional outcomes comparable to solid tumors. The proportion of cystic components did not adversely influence outcomes, supporting the application of standard resection techniques for both cystic and solid tumors. RAPN should be considered a reliable first-line surgical option for cystic tumors when technically feasible.