Comparison of robot-assisted partial nephrectomy for complex (RENAL scores ≥10) and non-complex renal tumors: A single-center experience

OBJECTIVES To compare functional and surgical outcomes of robot-assisted partial nephrectomy for complex tumors with RENAL scores ≥10 and non-complex tumors at a single academic institution. METHODS We retrospectively analyzed the data of all patients who underwent robot-assisted partial nephrectomy at Kobe University Hospital (Kobe, Hyogo, Japan) from 2011 to 2020. Functional and surgical outcomes for complex tumors (RENAL score ≥10) were compared with those of patients with non-complex tumors (RENAL <10). Outcomes analyzed included blood loss, warm ischemia time, console time, perioperative complications, and preoperative and postoperative renal function. RESULTS A total of 348 patients were included in our present study, with a median follow-up time of 35.1 months. Of these, 299 patients (85.9%) had non-complex tumors and 49 patients (14.1%) had complex tumors. Warm ischemia time and console time were significantly longer in the complex tumors group. Major perioperative complications (Clavien-Dindo classification system ≥3) were significantly more frequent in the complex tumors group than the non-complex tumor group (16.3% vs 5.7%, P = 0.018). Postoperative preservation of estimated glomerular filtration rate and percentage of chronic kidney disease upstage by 1 year were significantly inferior in the complex tumors group. The positive surgical margin rate was 0% and 0.3% in the complex and non-complex tumor groups, respectively. There were no significant differences in recurrence-free survival between the two groups (P = 0.11). CONCLUSIONS Robot-assisted partial nephrectomy for complex renal tumors is safe, with no difference in oncological outcomes, although more postoperative complications and decreased renal function can be observed than non-complex tumors.