Renal Cryoablation versus Robot-Assisted Partial Nephrectomy: Washington University Long-Term Experience.

Background and Purpose: AUA guidelines endorse partial nephrectomy as the preferred treatment for small renal masses, while considering patients with significant comorbidities potential candidates for ablative therapy. We compared perioperative, renal functional, and oncological outcomes of renal cryoablation and robot-assisted partial nephrectomy (RAPN) based on our long-term institutional experience. Materials and Methods: A retrospective review evaluated 267 patients who underwent laparoscopic or percutaneous cryoablation (7/2000-6/2011) and 233 patients who underwent RAPN (6/2007-9/2012) for enhancing renal masses at Washington University. Results: The perioperative complication rate was 8.6% in the cryoablation group vs. 9.4% in the RAPN group (p=0.75). There was no significant difference in complication risk between the two treatment modalities on multivariate analysis. Glomerular filtration rate (eGFR) at last follow-up was 6.0% lower than preoperative eGFR in the cryoablation group and 13.0% lower in the RAPN group (p<0.01). The advantage of cryoablation in preserving renal function persisted on multivariate analysis (p=0.02). In patients with pathologically proven renal cell carcinoma, 5-year Kaplan-Meier disease-free survival (DFS), cancer-specific survival (CSS), and overall survival was 83.1%, 96.4%, and 77.1% in the cryoablation cohort vs. 100%, 100%, and 91.7% in the RAPN group. Mean time to recurrence was 16.2 months (range=0.03-42.0). Cryoablation was associated with increased recurrence risk (HR=11.4, p=0.01) on multivariate analysis. Conclusions: Cryoablation and RAPN are safe alternatives for managing renal masses amenable to nephron-sparing interventions, offering acceptable morbidity and excellent renal preservation. While RAPN offers improved DFS, for those willing to undergo close postoperative monitoring and accept the potential need for retreatment of recurrent disease, cryoablation offers excellent long-term CSS.