Percutaneous Microwave Ablation of Complex Cystic Renal Masses: Assessment of Technique, Safety, and Clinical Outcomes.

PURPOSE: To evaluate the technique, safety, and clinical outcomes of computed tomography (CT)-guided microwave ablation of cystic renal masses.

MATERIAL AND METHODS: An institutional database was used to identify consecutive patients with cystic renal masses that were treated with percutaneous microwave ablation. Preablation CT or magnetic resonance (MR) images were reviewed by 2 board-certified, fellowship-trained abdominal radiologists to classify cystic renal masses as complex or Bosniak III/IV masses. A third board-certified, fellowship-trained radiologist served as the tiebreaker for cases of discordance between the 2 readers. Tumor factors such as size and renal nephrometry score were recorded. Ablation technique, including management of the cystic component of the tumors, adjunctive maneuvers, and power and time for the ablations, were recorded. Technical success, primary and secondary effectiveness, adverse events, and clinical outcomes were assessed.

RESULTS: Fifty-six patients with 61 cystic renal masses underwent CT-guided microwave ablation. The diagnostic yield of biopsy of cystic renal masses was 87%. Fifty of the 61 cystic renal masses (82%) were renal cell carcinoma. Primary technical success rate was 95.1%. There was no significant change in serum creatinine or estimated glomerular filtration rate before and after ablation. There were 4 (8%) Society of Interventional Radiology (SIR) Grade 1 adverse events, all of which were small perinephric hematomas.

CONCLUSIONS: CT-guided microwave ablation of cystic renal masses, including cystic renal cell carcinoma, is technically feasible, highly effective, and associated with a low adverse event rate.