Percutaneous cryoablation of renal masses ≥ 3cm: efficacy and safety in treatment of 108 patients

Purpose: To evaluate our single institution experience with percutaneous cryoablation of renal masses ≥ 3cm in diameter for complications and short-term outcomes. Patients and Methods: Between March 2003 and February 2009, 108 patients with 110 renal masses ≥ 3cm in diameter were treated with percutaneous cryoablation therapy. Technical success of the ablation procedure, complications, and evidence for local tumor recurrence were evaluated for each patient. Results: Average maximal renal tumor diameter was 4.1cm (range 3.0-8.3 cm; standard deviation 1.1cm). A single cryoablation procedure was performed for treatment of each patient. A technically successful ablation was achieved for 107 of 110 (97%) tumors. The three technical failures all resulted from incomplete cryoablation of the deepest margin of a centrally located renal tumor. A total of 9 severe adverse events occurred in six patients, resulting in an 8% major complication rate. Two patients in whom major complications developed were part of the group of only four patients for whom ablation was performed for tumors >7cm in diameter. There were no procedural-related deaths. No evidence for local tumor recurrence was identified in any patients with follow-up contrast-enhanced CT or MRI obtained 3 months or longer from the time of the ablation. Follow-up in these patients averaged 15 months (range 3-42 mos). Conclusion: Percutaneous cryoablation of renal masses ≥ 3 cm in diameter can be performed with high technical success and low complication rates. Extra scrutiny is needed during cryoablation of central renal masses to make sure the ablation zone extends to include the deepest margin of the tumor. Although our experience is limited, percutaneous cryoablation of renal tumors >7cm in diameter may be associated with increased complications. The lack of local renal tumor recurrences seen in this study on short-term follow-up is encouraging, but long-term follow-up remains necessary to ensure treatment durability.