Ten-Year Experience with Percutaneous Cryoablation of Renal Tumors: Tumor Size Predicts Disease Progression.

INTRODUCTION: Percutaneous cryoablation (PCA) has emerged as an alternative to extirpative management of small renal masses (SRMs) in select patients, with a reduced risk of perioperative complications. Although disease recurrence is thought to occur in the early postoperative period, limited data on long-term oncologic outcomes has been published. We reviewed our ten-year experience with PCA for SRMs and assessed predictors of disease progression. MATERIALS AND METHODS: We reviewed our prospectively-maintained database of patients who underwent renal PCA from March 2005 to December 2015 (n=308). Baseline patient and tumor variables were recorded, and postoperative cross-sectional imaging was examined for evidence of disease recurrence. Disease progression was defined as the presence of local recurrence or new lymphadenopathy/metastasis. RESULTS: Mean patient age was 67.2+11 years, mean tumor size was 2.7+1.3 cm, and mean nephrometry score was 6.8+1.7. At mean follow-up of 38 months, local recurrence and new lymphadenopathy/metastasis occurred in 10.1% (31/308) and 6.2% (19/308) of patients, respectively. Excluding patients with solitary kidney and/or VHL, local recurrence and new lymphadenopathy/metastasis occurred in 8.6% (23/268) and 1.9% (5/268) of cases, respectively. Kaplan-Meier estimated disease-free survival was 92.5% at 1 year, 89.3% at 2 years, and 86.7% at 3 years post-PCA. Increasing tumor size was a significant predictor of disease progression (HR 1.32 per 1 cm increase in size, P = 0.001). CONCLUSIONS: PCA is a viable treatment option for patients with SRMs. Increasing tumor size is a significant predictor of disease progression following PCA.