Abstract No. 103: CT-Guided Percutaneous Cryoablation of Unresectable Renal Tumors: Initial Outcomes

To determine the technical and clinical outcome of percutaneous cryoablation of unresectable renal tumors. Patients with unresectable suspicious renal masses were treated from March 2005 to August 2007. Patients were excluded from surgery secondary to comorbidities and/or limited renal function. All procedures were performed with moderate sedation under CT-fluoroscopic guidance and monitoring. 2 different cryoablation systems were used; Endocare (Irvine, CA) and Galil Medical (Yokneam, Israel). 2 freeze/thaw cycles (10 and 5 minutes respectively) were performed for each lesion. Follow-up imaging (CT or MRI) was performed at 1, 4-6 and 12 months after the procedure, and annually thereafter. Complications were tracked using the Common Terminology Criteria for Adverse Events version 3 (CTCAE v3) of the National Cancer Institute. 36 treatments were performed on 34 lesions in 32 patients. Mean patient age was 68 ± 9.5 years (range: 46-86). 50% of lesions were in the right kidney. Lesion location was 50% lower pole, 23.5% upper pole and 26.5% interpolar. 82% of lesions were exophytic, 3% central and 15% both. 91% (n=31/34) of lesions were posterior. 88% (n=30/34) of lesions were solid in consistency. Mean number of cryoprobes used was 2.8 per lesion (range:1-6). Clinical success at initial follow-up was 93.8% (n=30/32). 2 patients had residual tumor after initial ablation that was successfully treated at a second visit. Mean follow-up was 193 days ± 177 (range: 25-727 days). No local progression has been identified. Grade 3 complications occurred in 8.3% (n=3/36) procedures according to CTCAE v3. One patient developed a perinephric hematoma that required transfusion. One patient had post ablation hematuria requiring transfusion after ablating a tumor that involved an upper pole calyx. The final patient developed a persistent urinary leak that was eventually managed by elective nephrectomy with good outcome. Cryoablation of renal tumors in non-surgical candidates is a safe treatment option with promising early results. Longer term follow-up will be essential to expand into treatment of potential surgical candidates.