Microwave vs radiofrequency ablation for small renal masses: perioperative and oncological outcomes

Objective To conduct a comprehensive comparison of microwave ablation (MWA) vs radiofrequency ablation (RFA) outcomes in the treatment of small renal masses (SRMs), specifically: TRIFECTA ([i] complete ablation, [ii] absence of Clavien–Dindo Grade ≥III complications, and [iii] absence of ≥30% decrease in estimated glomerular filtration rate) achievement, operative time (OT), and local recurrence rate (LRR). Patients and Methods We retrospectively analysed 531 patients with SRMs (clinical T1a–b) treated with MWA or RFA at a single centre (2008–2022). First, multivariable logistic regression models were used for testing TRIFECTA achievement. Second, multivariable Poisson regression models were used to evaluate variables associated with longer OT. Finally, Kaplan–Meier plots depicted LRR over time. All analyses were repeated after 1:1 propensity score matching (PSM). Results Of 531 patients with SRMs, 373/531 (70.2%) underwent MWA and 158/531 (29.8%) RFA. MWA demonstrated superior TRIFECTA achievement (314/373 [84.2%]) compared to RFA (114/158 [72.2%], P = 0.001). These differences were driven by higher rates of complete ablation in MWA‐ vs RFA‐treated patients (348/373 [93.3%] vs 137/158 [86.7%], P