Percutaneous Radiofrequency Ablation of Sporadic Bosniak III or IV Lesions: Treatment Techniques and Short-Term Outcomes

Abstract

PurposeTo evaluate retrospectively the techniques and outcomes of percutaneous radiofrequency (RF) ablation for treatment of Bosniak III or IV lesions. Materials and MethodsBetween August 2006 and August 2013, 30 patients (25 men and 5 women; mean age, 57 y; range, 22–77 y) with 35 nonhereditary Bosniak III (n = 15) or IV (n = 20) lesions underwent computed tomography–guided RF ablation. The mean size of the lesions was 2.8 cm ± 0.9 (range, 1.1–4.3 cm). The mean follow-up period was 24 months ± 16 (range, 6–70 mo). Duration of ablation, number of sessions and electrode repositions, primary and secondary effectiveness rates, major complication rate, reduction rate of lesion size, estimated glomerular filtration rate (GFR), and local tumor progression were recorded. Wilcoxon signed rank test was used for statistical analysis. ResultsMean duration of ablation was 18 minutes ± 14 (range, 2–65 min), and median number of sessions was one. Median number of electrode repositions was 1.0 ± 1.6 (range, 0–6). Primary and secondary effectiveness rates were 97.1% (34 of 35) and 100% (1 of 1), respectively. Mean reduction rate of lesion size was significantly greater from before RF ablation to 1 month after RF ablation (7.1 mm/mo ± 4.5) compared with from 1 month after RF ablation to the last month of follow-up (0.2 mm/mo ± 0.2; P < .0001). Mean GFR after RF ablation (65.4 mL/min/1.73 m2 ± 26.1) was minimally reduced but significantly different from mean GFR before RF ablation (76.0 mL/min/1.73 m2 ± 28.4; P < .0001). Major complications occurred in 2 of 35 RF ablation sessions for a rate of 5.7%, resulting from pneumothorax. Of 30 patients, 29 (96.7%) did not have local tumor progression or metastasis for 2 years. ConclusionsPercutaneous RF ablation is technically feasible and yields excellent short-term outcomes in treating sporadic Bosniak III or IV lesions.