Percutaneous Radiofrequency Ablation for Bosniak III-IV Cysts: A 5-Year Institutional Experience

Percutaneous radiofrequency ablation (RFA) is an increasingly adopted treatment for small solid renal masses. However, its safety and oncological effectiveness in complex renal cysts, classified as Bosniak III and IV, remain poorly characterized. We aimed to evaluate oncological outcomes and safety of RFA in patients with Bosniak III-IV cysts.

We retrospectively identified patients who underwent ultrasound-guided percutaneous RFA for Bosniak III-IV renal cysts at our institute between June 2017 and February 2025. Clinical, radiological, histological, and functional data were collected. Technical success was defined as the absence of enhancement on intra- and postprocedural contrast-enhanced ultrasound.

Overall, 34 patients underwent RFA for 38 cT1a complex renal cysts (mean diameter 2.11 ± 0.7 cm): 8 (21.1%) were Bosniak III and 30 (78.9%) Bosniak IV. Two patients with Bosniak III cyst were subsequently excluded from oncological analyses because of benign or nondiagnostic histology report. Technical success was achieved in 100% of cases. Postprocedural laboratory values showed Δ creatinine 0.02 mg/dL (interquartile range [IQR]: 0.01-0.05; p = 0.001), Δ estimated glomerular filtration rate -0.80 mL/min/1.73 m² (IQR: -2.0-0.0; p = 0.001), and Δ hemoglobin -0.2 g/dL (IQR: -1.0-0.0; p = 0.001). Postprocedural complications were observed in 2/34 patients (5.8%), both involving hemorrhages, one of which required transarterial embolization (Clavien-Dindo grade III). At a median follow-up of 62.5 months (IQR: 18-72.5), local recurrence occurred in 2/32 patients (6.2%). No cases of systemic progression or cancer-specific mortality rate were observed.

Ultrasound-guided RFA appears to be a safe and feasible nephron-sparing option for the management of Bosniak III-IV renal cystic lesions in selected patients.