Robot-assisted partial nephrectomy versus standard laparoscopic partial nephrectomy for renal hilar tumor: A prospective multi-institutional study

Objective: To investigate whether robot-assisted partial nephrectomy compared with laparoscopic partial nephrectomy is effective for renal hilar tumor removal. Methods: This was a prospective, multicenter, single-arm, open-label trial with a 2-year enrollment period. A total of 22 academic hospitals in Japan participated in the present study. Comparison with historical control values from reported studies of laparoscopic partial nephrectomy was carried out. The warm ischemia time and positive surgical margin rate were set as primary perioperative and oncological outcomes. In the historical control group, these were 27.7 min and 13%, respectively. Results: The analysis population included 105 participants. The mean warm ischemia time was 20.2 (95% confidence interval 16.7–21.8; P < 0.0001 vs 27.7). Two of 103 participants (1.9%) had a positive surgical margin (95% confidence interval 0.5–6.8%). Both results satisfy the prespecified decision criteria for the superiority of robot-assisted partial nephrectomy over the historical control of laparoscopic partial nephrectomy. Resected weight and preoperative estimated glomerular filtration rate were predictive factors of functional loss of the partially nephrectomized kidney after robot-assisted partial nephrectomy. Conclusion: Robot-assisted partial nephrectomy for clinical T1 renal hilar tumors results in shorter warm ischemia time than and comparable positive surgical margin rate to those reported for laparoscopic partial nephrectomy.