Percutaneous cryoablation of masses in a solitary kidney

OBJECTIVE. The purpose of this study was to determine the effect of percutaneous cryoablation of tumors in a solitary kidney on renal function, treatment-related complications, and local tumor control. MATERIALS AND METHODS. A retrospective review of the cases of patients with a solitary kidney treated with percutaneous renal cryoablation from March 2003 through November 2008 was performed. Renal function was analyzed with serum creatinine concentration and glomerular filtration rate measured before ablation, on the first day after ablation, 3-6 months after ablation, and at the most recent evaluation on record at our institution. Index tumor size, ice ball size, and local tumor control were tabulated after review of preablation and postablation images. RESULTS. Thirty-one patients with 38 tumors (mean maximum diameter, 3.0 cm; range, 1.7-7.3 cm) were treated with 35 cryoablation procedures. After a mean follow-up period of 14 months (range, < 1-42 months), 29 patients had a 0.1-mg/dL median increase in creatinine concentration (p = 0.0089) and 4.7-mL/min/1.73 m² median decrease in glomerular filtration rate (p = 0.0335) from preablation levels. Fifteen of 25 patients with 3 months or more of renal function follow-up had a decrease in renal function. Ten of these 15 patients (67%) had a history of previous renal ablation or partial nephrectomy involving the same solitary kidney. No patient needed dialysis. Seven grade 3 or greater complications (Common Terminology Criteria for Adverse Events) occurred after the 35 procedures (20% complication rate). The median hospital stay was 1 day (range, 1-19 days). The local tumor control rate was 92%. CONCLUSION. Percutaneous cryoablation is effective in the management of renal tumors in patients with a solitary kidney, causing minimal loss of renal function. Patients who have previously undergone partial nephrectomy or ablation in a solitary kidney may be more susceptible to renal function loss than patients who have not undergone these procedures.