04:03 PM Abstract No. 90 Clinical outcomes of percutaneous cryoablation for small renal masses: a 10-year experience

Abstract

Percutaneous cryoablation is safe and effective for the treatment of renal tumors, but studies examining long-term clinical outcomes are limited. The purpose of this study was to evaluate the effectiveness and adverse outcomes in a large cohort of patients undergoing percutaneous cryoablation for solid renal masses. This retrospective analysis included all 298 percutaneous cryoablation procedures (306 masses in 278 patients) performed between July 2007 and July 2018 at a single institution. The mean age in the cohort was 66.1 years (range, 30 – 93; 65.8% male). 244 masses were biopsy-proven renal cell carcinoma (RCC). Cross-sectional imaging analysis of recurrence rates, tumor staging, and long-term efficacy included only ablations for RCC. All patients were included in the analysis of procedure-related complications, including those for whom biopsy was not performed (n=8) and those with benign (n=15) or non-diagnostic (n=39) pathology. Complications were categorized according to the SIR Adverse Event Classification. The mean maximal tumor diameter was 2.3 cm (range, 0.7 - 6.6 cm). The average length of stay after cryoablation was 1.2 days (range, 1 - 8 days). Major complications occurred in 3.0% of procedures (n=9), with none resulting in death or permanent disability. There was no significant difference in pre-procedural estimated glomerular filtration rate (eGFR) and the eGFR at first follow-up (p=0.98). Among RCC patients with follow-up imaging available (n=219), the mean imaging follow-up period was 25.2 months (range, 1 – 100 months). Complete response on initial follow-up imaging was achieved in 96.3% (211 of 219) after a single session and 99.1% (217 of 219) after two sessions. Of the RCC patients achieving complete response, local recurrence during the follow-up period was seen in 2.3% (5 of 217). New metastatic disease developed in 2.7% (6 of 219) of RCC patients during follow-up. Percutaneous cryoablation is a safe and effective alternative to partial nephrectomy in the treatment of small renal masses.