Percutaneous cryoablation of 40 solid renal tumors with US guidance and CT monitoring: initial experience

PURPOSE: To retrospectively determine the safety and effectiveness of percutaneous cryoablation, monitored with computed tomography (CT), for the treatment of solid renal masses. MATERIALS AND METHODS: This study was compliant with the Health Insurance Portability and Accountability Act and had institutional review board approval; informed consent was waived. From March 12, 2003, through August 4, 2005, 23 men and 17 women (mean age, 76 years +/- 9.7 [standard deviation]; range, 53-92 years), each with a single renal tumor, underwent one percutaneous cryoablation treatment session that combined ultrasonographic (US) guidance and CT monitoring. Technical success was defined as extension of the visible ice ball 5 mm beyond the tumor margin. Local tumor progression was defined as any tumor with intralesional enhancement or a serial increase in tumor size when compared with that on images obtained immediately after ablation. Tumor characteristics, complications, and follow-up were evaluated. RESULTS: The maximum diameter of the 40 treated lesions ranged from 1.5 to 7.2 cm (mean, 3.4 cm +/- 1.3). Twenty (50%) of 40 tumors were 3 cm or larger in diameter. Nineteen tumors (48%) extended into the renal sinus fat. One complication (2%) conformed to a grade 3 event, as determined with the Common Terminology Criteria for Adverse Events (version 3.0) of the National Cancer Institute; the overall complication rate was 8%. Thirty-eight (95%) of 40 cryoablation procedures were technically successful. Twenty-nine patients underwent follow-up (mean, 8.0 months +/- 4.3; range, 1.2-18.4 months); no local tumor recurrence was found. CONCLUSION: Percutaneous cryoablation with US guidance and CT monitoring is safe and effective for the treatment of solid renal tumors. Longer follow-up should provide further proof of the effectiveness of this technique.