Microwave versus cryoablation and radiofrequency ablation for small renal mass: a multicenter comparative analysis

Background: Ablative techniques emerged as effective alternative to nephron-sparing surgery for treatment of small renal masses. Radiofrequency ablation (RFA) and cryoablation (CRYO) are the two guidelines-recommended techniques. Microwave ablation (MWA) represents a newer technology, less described. The aim of the study was to compare outcomes of MWA to those of CRYO and RFA. Methods: Retrospective investigation of patients who underwent MWA, CRYO, or RFA from seven high-volume US and European centers was performed. The first group included patients who underwent CRYO or RFA; the second MWA. We collected baseline characteristics, clinical, intraoperative, and postoperative data. Oncological data included technical success, local recurrence, and progression to metastasis. Multivariate analysis was performed to find predictors for postoperative complications. A composite outcome of "trifecta" was used to assess surgical, functional, and oncological outcomes. Results: 739 patients underwent CRYO or RFA and 50 MWA. CRYO/RFA group had significantly longer operative time (P