Intermediate outcomes and predictors of efficacy in the radiofrequency ablation of 100 pathologically proven renal cell carcinomas.

ABSTRACT

PURPOSE: To determine oncologic outcomes and predictors of primary efficacy, including RENAL nephrometry scores (radius, exophytic/endophytic properties, nearness of tumor to collecting system or sinus, anterior/posterior, location relative to polar lines), after percutaneous radiofrequency (RF) ablation of proven renal cell carcinoma (RCC). MATERIALS AND METHODS: Patients who underwent percutaneous computed tomography- and ultrasound-guided RF ablation for histologically proven RCC from 2004 to 2011 were evaluated. Clinical data, pathologic findings, technical details, and outcomes were reviewed. Univariate and multivariate logistic regression analysis was performed to determine predictors of primary technique effectiveness and complications. Local tumor progression-free, metastasis-free, and overall survival were calculated. One hundred RCC lesions underwent 115 RF ablation sessions in 84 patients. Median follow-up was 24 months (mean, 27 mo; range, 1-106 mo). RESULTS: Efficacy of RF ablation was defined per International Working Group of Image-Guided Tumor Ablation criteria. Total, primary, and secondary technique effectiveness rates were 95% (95 of 100), 86% (86 of 100), and 9% (nine of 100), respectively. Primary efficacy was associated with size (P < .001), proximity to collecting system (P = .001), RENAL nephrometry score (P < .001), and number of ablation zones (P < .001). Complications occurred in 13% of patients, without procedure-related deaths. The median 2.1-year local progression-free, metastasis-free, disease-specific, and overall survival rates were 86%, 98.7%, 100%, and 97.6%, respectively. CONCLUSIONS: Percutaneous image-guided RF ablation for RCC provides excellent intermediate oncologic control. Location, size, proximity to the collecting system, low RENAL nephrometry score, and number of ablation zones predict primary efficacy.