Percutaneous cryoablation of solitary sporadic renal cell carcinomas

What's known on the subject? and What does the study add? Percutaneous renal cryoablation is a safe and effective treatment for patients with small renal masses, who are poor surgical candidates. Oncological outcomes from previous percutaneous ablation studies are difficult to interpret because of the large number of patients treated with a history of RCC (38% in our experience) and the large number of treated renal masses without a pathology-proven diagnosis. This cryoablation study addresses these issues by evaluating only solitary, sporadic biopsy-proven RCC. Oncological outcomes and complications were also evaluated by tumour T-stage, which allows some degree of comparison with previously published surgical results.

• To evaluate retrospectively our single institution experience with percutaneous cryoablation of solitary, sporadic renal cell carcinomas (RCCs), and to compare the efficacy and safety of this technique for treatment of different T-stage RCC.

• 116 patients were treated with percutaneous cryoablation for a solitary, sporadic biopsy-proven RCC in a single treatment session between November 2003 and November 2010. • The technical success of the ablation procedure, complications and evidence for local or metastatic tumour recurrence were evaluated for each patient.

• 83 patients (72%) were treated for a stage T1a RCC, 27 patients (23%) for a stage T1b RCC, and six patients (5%) for a stage T2 RCC. • Technical success was achieved in the treatment of 115 of 116 (99%) renal tumours. The single technical failure occurred in the treatment of a 4.3-cm RCC. • Local recurrent tumour was identified in one of 88 patients (1%) with follow-up computed tomography (CT) or magnetic resonance imaging available for review >3 months from the time of ablation. The median (range) imaging follow-up in these patients was 21 (3-73) months. The local tumour recurrence was identified on CT 11 months after the ablation procedure in a patient treated for a 2.7 cm RCC. • None of the patients developed metastatic RCC. • The major complication rate was 4% for patients with stage T1a tumours, 15% for those with stage T1b tumours, and 33% for those with stage T2 tumours. There were no procedural-related deaths.

• Percutaneous renal cryoablation of RCC can be performed with high technical success in patients with tumours up to, and beyond 7 cm in maximum diameter. • The tumour recurrence rate after percutaneous renal cryoablation was low, and recurrence was not related to tumour size in this group of patients. • Statistically significant higher complication rates were seen with treatment of larger (higher T-stage) RCCs.