Safety, efficacy, and mid-term oncological outcomes of computed tomography-guided cryoablation of T1 renal cancer.

BACKGROUND: Cryoablation is a promising minimally invasive, nephron-sparing treatment of small renal carcinoma (RCC) in co-morbid patients. PURPOSE: To assess the safety, efficacy, and cancer-specific outcomes of computed tomography (CT)-guided cryoablation of stage T1 (RCC). MATERIAL AND METHODS: A retrospective evaluation of 122 consecutive patients with 128 tumors treated with cryoablation during 2016-2017. All patients had biopsy-verified T1 RCC. RESULTS: Median age was 69 years (IQR=59-76); 69% were male. Median tumor size was 26 mm (± 20-33); 9% were stage T1b. Mean follow-up time was 36.3±12.0 months. In total, 14 (11%) procedures led to complications, of which 4 (3%) were intraoperative, 5 (4%) appeared ≤30 days and 5 (4%) >30 days after treatment. Major complications arose after 4 (3%) procedures. Statistically significant associations were found between major complications and stage T1b (P = 0.039), RENAL score (P = 0.010), and number of needles used in cryoablation (P = 0.004). Residual tumor was detected after 4 (3%) procedures and 5 (4%) tumors had local tumor progression. Of 122 patients, 3 (2%) advanced to metastatic disease. Significant statistical associations were found between local tumor progression and T1b stage tumors and number of needles used in cryoablation (P = 0.05 and P = 0.004, respectively). For patients with T1a tumors, the one- and three-year disease-free survival was 98% and 95%, respectively, and for T1b 100% after one year and 75% after three years. CONCLUSIONS: This study showed that cryoablation is a safe and effective treatment of stage T1 RCC and suggests that in selecting candidates for cryoablation of RCC, the tumor characteristics are more critical than patients' baseline health status.