Long-term functional and oncological outcomes of robot-assisted partial nephrectomy for cystic renal tumors: a single-center retrospective study.

OBJECTIVES To evaluate the outcomes of robot-assisted partial nephrectomy (RAPN) in cystic renal tumors. MATERIALS AND METHODS We retrospectively analyzed patients who underwent RAPN for either cystic (n = 46) or solid (n = 271) renal tumors at Fujita Health University between 2010 and 2019. Cystic renal tumors were diagnosed using cross-sectional imaging. Perioperative, oncological, and functional outcomes were assessed. RESULTS The median follow-up periods were 38, 41, and 37 months in the total, cystic, and solid groups, respectively. Most patient characteristics were similar among both groups, while the median age of the cystic group was significantly lower than that of the solid group (P = 0.02). Most perioperative variables and complications were comparable between the two groups. There was no significant difference between the groups in perioperative renal function. The estimated glomerular filtration rate (eGFR) preservation rates were 93.1% and 89.2% in the cystic and solid groups, respectively (P = 0.17). The cystic group showed a higher benign histology rate (19.6% vs. 7%) and lower Fuhrman grade than the solid group (24.3% vs. 15.1% in grade 1, 73% vs. 81.3% in grade 2), although there was no statistically significant difference between the two groups. In the solid group, 10 patients (3.7%) experienced recurrence, and two patients (0.7%) died of renal cell carcinoma, while none of the patients with cystic tumors experienced recurrence. There was no statistically significant difference between the cystic and solid tumors with respect to 5-year recurrence-free survival (P = 0.18), cancer-specific survival (P = 0.55), and overall survival (P = 0.35). CONCLUSIONS RAPN for cystic renal tumors appears to be safe and feasible with perioperative, long-term functional, and oncological outcomes comparable to those in solid tumors. RAPN can be a safe and effective surgical option for cystic renal tumors.