Oncologic outcomes and safety of percutaneous cryoablation for biopsy-proven renal cell carcinoma up to 4 cm in diameter: a prospective observational study

Background Percutaneous cryoablation is widely used for the treatment of renal cell carcinoma. We prospectively evaluated the oncologic outcomes and safety of percutaneous cryoablation for the treatment of tumors <= 4 cm in diameter. Methods We included patients aged >= 20 years, who had histologically proven renal cell carcinoma, tumor diameter <= 4 cm, a performance status of <= 1, acceptable laboratory parameters, were inoperable or refused to undergo surgery, and had signed a written informed consent. The primary endpoint was the cause-specific survival rate. The secondary endpoints were overall and progression-free survival, and adverse event frequency and grade. All procedures were percutaneously performed under computed tomography fluoroscopy guidance. Results From October 2013 to October 2015, 33 patients (mean age: 68 +/- 14 years; sex: six women, 27 men) were enrolled. The mean tumor diameter was 2.1 +/- 0.6 (range 1.0-3.4) cm. The median follow-up period was 60.1 (range 18.4-76.6) months. One patient died of non-renal cell carcinoma-related disease 46 months after percutaneous cryoablation. The cause-specific and overall survival rates were 100% and 96.8% at 3 years, and 100% and 96.8% at 5 years, respectively. There was no local tumor progression or distant metastasis. The incidence of severe urological (urinary fistula and perinephric infection) and non-urological adverse events (increased creatine kinase and skin ulceration) was 6% each. Conclusion Percutaneous cryoablation for renal cell carcinoma <= 4 cm in diameter achieved good tumor control with a low complication frequency.