Intermediate to Long-Term Clinical Outcomes of Percutaneous Cryoablation for Renal Masses

Purpose: The purpose of this study was to evaluate the effectiveness and adverse outcomes of percutaneous cryoablation (CA) for treatment of renal masses in a large cohort of patients. Materials and Methods: This retrospective analysis included 299 CA procedures (297 musses in 277 patients) performed between July 2007 and May 2018 at a single institution. The mean patient age was 66.1 years (range, 30-93 years) with 65.8% being male. A total of 234 (78.8%) masses were biopsy-proven renal cell carcinoma (RCC). The mean maximal tumor diameter was 2.5 cm (range, 0.7-6.6 cm). Efficacy was assessed only for ablations of biopsy-proven RCC, whereas the evaluation of adverse events and renal function included all masses. Complications were graded according to the Society of International Radiology classification. Results: Major complications occurred in 3.0% of procedures (n - 9), none of which resulted in death or permanent disability. The mean imaging follow-up period was 27.4 months (range. 1-115) for the 199 RCC patients (204 ablated tumors) with follow-up imaging available. Complete response on initial follow-up imaging at mean 4.2 months (range, 0.3-75.6) was achieved in 195 of 204 tumors (95.6%) after a single session and in 200 of 204 tumors (98.0%) after I or 2 sessions. Of the RCC patients achieving complete response initially, local recurrence during the follow-up period occurred in 3 of 200 tumors (1.5%). Metastatic progression occurred in 10 of 193 (5.2%) RCC patients without prior metastatic disease during follow-up. Conclusions: CA for renal masses is safe and remains efficacious through intermediate-and long-term follow-up.