Open Partial Nephrectomy vs. Robot-assisted Partial Nephrectomy for a Renal Tumor Larger than 4 cm: a Propensity Score Matching Analysis

Background: To compare open partial nephrectomy (OPN) and robot-assisted partial nephrectomy (RAPN) in the management of renal tumors larger than 4 cm. Methods: Clinical records of 220 patients who underwent OPN or RAPN for a single renal tumor >= 4.0 cm with a normal contralateral kidney were reviewed. After determining the propensity score, surgical parameters, functional outcomes, and oncological outcomes were compared between OPN (n = 67) and RAPN (n = 67) groups of patients. Results: The RAPN group had longer operation time (149.0 min vs. 173.3 min, P = 0.030) and longer ischemic time (20.3 min vs. 29.4 min, P = 0.001), but shorter hospital stay (8.2 days vs 6.0 days, P = 0.001) than the OPN group. Estimated blood loss (P = 0.053), pain visual analog score at 1 day postoperatively (P = 0.194), and complications of grade III or higher (P = 0.403) were similar between OPN and RAPN groups. There was no radical conversion or positive surgical margin in either group. Mean change in 6-month estimated glomerular filtration rate was significantly better in the RAPN group (-8.2 vs. -3.1, P = 0.027). There was no statistical difference in recurrence-free survival (P = 0.970) or cancer-specific survival (P = 0.345) between the two groups. Conclusion: RAPN is a safe and feasible surgical modality comparable to OPN for managing renal tumors larger than 4 cm in terms of surgical, functional, and oncological outcomes.