Is Extensive Parenchymal Resection during Robotic Partial Nephrectomy Justified? A Match-Paired Comparison of Two Extirpative Surgical Modalities for Treatment of a Complex Renal Neoplasm

Objective: To analyze the outcomes of robotic partial nephrectomy (RPN) in patients where nephron-sparing surgery would have mandated a large amount of renal volume resection. Methods: Patients undergoing RPN with extensive volume resection (≥30%), from 2006 to 2014, were identified. Pre- and postoperative CT/MRI-based volumetric assessment of the operated kidney was performed. To address the possible benefits of RPN, we matched this cohort to patients undergoing laparoscopic radical nephrectomy (LRN). The groups were matched for tumor size, R.E.N.A.L. nephrometry score, age-adjusted Charlson comorbidity index (ACCI), and preoperative estimated glomerular filtration rate (eGFR). Demographics, perioperative, functional, and oncologic outcomes were compared between the groups. Multivariable analysis of factors predicting chronic kidney disease (CKD) upstaging (type of surgery, R.E.N.A.L. score, ACCI, and baseline eGFR) was performed. Results: In total, 52 patients undergoing RPN were matched to 52 LRN patients. The median R.E.N.A.L. score (interquartile range) was 9 (9-10) for both groups. Demographic variables were comparable between the groups. The median renal volume preservation in the RPN group was 57.0% (47.2-67.2). The rates of overall and major complications were comparable between RPN and LRN. The RPN group had higher overall eGFR preservation (75.8% vs 68.5%; p = 0.01) and a lower rate of CKD upstaging (26.9% vs 50.6%; p = 0.001). On multivariable analysis, LRN and baseline eGFR were significant predictors of CKD upstaging (odds ratio [OR] 4.26; 95% CI [1.80-10.12]; p = 0.001 and OR 0.98; 95% CI [0.96-0.99]; p = 0.03, respectively). During the median follow-up time of 21 (9-36) months, local recurrence, metastasis, and cancer-specific and overall survival were comparable between RPN and LRN. Conclusion: RPN requiring extensive volume resection provides renal functional preservation without significant increase in surgical complications or compromising short-term oncologic outcomes.