Percutaneous Microwave Ablation is Comparable to Cryoablation for the Treatment of T1a Renal Masses: Results From a Cross-Sectional Study

Introduction: Percutaneous microwave ablation (MWA) of renal masses (RM) is still considered experimental as opposed to established procedures such as cryoablation (CA). We aimed to compare perioperative, functional and oncological outcomes of patients with RM treated with CA and MWA. Materials and Methods: Data from 116 (69.9%) and 50 (30.1%) patients treated with CA and MWA for RM were analyzed. Patients’ demographics and perioperative data were collected including nephrometry scores, complications, pre- and postprocedural renal function. Tumor persistence and recurrence were recorded. Descriptive statistics compared functional outcomes between groups. Cox regression analyses tested risk factors associated with recurrence. Results: Groups were similar in terms of RM diameter, nephrometry scores and histology distribution. Median follow-up was 26 (13-46) and 24 (14-36) months for CA and MWA, respectively. The rate of overall (36.2% for CA vs. 24% for MWA, P=.1) and major (Clavien ≥ 3a) complications (1.7% vs. 5.4%, P =.1) were similar among groups. The median decline of renal function after 6 months follow-up did not differ between CA and MWA (P =.8). Tumor persistence [4.3% vs. 12%] and recurrence [9.5% and 7.1%] rates were similar for CA and MWA. Three years recurrence free and overall survival were 91% versus 95% (log-rank P =.77) and 80 versus 88% (log-rank P =.23) in the CA and MWA groups, respectively. At Cox analysis no predictors were found associated with recurrence. Conclusion: Despite being considered still experimental, MWA showed comparable outcomes relative to CA in terms of safety, preservation of renal function and oncological efficacy.