Durable Oncologic Outcomes After Radiofrequency Ablation Experience From Treating 243 Small Renal Masses Over 7.5 Years

BACKGROUND: Long-term oncologic outcomes for renal thermal ablation are limited. The authors of this report present their experience with radiofrequency ablation (RFA) therapy for 243 small renal masses (SRMs) over the past 7.5 years. METHODS: The authors' institutional, prospectively maintained RFA database was reviewed to determine intermediate and long-term oncologic outcomes for patients with SRMs (generally <4 cm) who underwent RFA. Particular attention was placed on patients who had a minimum 3 years of follow-up. Patients were excluded from the analysis if they had received previous treatment for renal cell carcinoma (RCC) on the ipsilateral kidney or if they did not have at least 1 imaging study available for follow-up. RESULTS: Two hundred eight patients (with 243 SRMs) who had no evidence of previous ipsilateral renal cancer treatment underwent RFA and had follow-up imaging studies available for review. Overall, tumor size averaged 2.4 cm, and follow-up ranged from 1.5 months to 90 months (mean, 27 months). Of the 227 tumors (93%) that underwent preablation biopsy, RCC was confirmed in 79%. The initial treatment success rate was 97%, and the overall 5-year recurrence-free survival rate was 93% (90% for 160 patients who had biopsy-proven RCC). During follow-up, 3 patients developed metastatic disease, and 1 patient died of RCC, yielding 5-year actuarial metastasis-free and cancer-specific survival rates of 95% and 99%, respectively. CONCLUSIONS: RFA provided successful treatment of SRMs and produced a low rate of recurrence as well as prolonged metastasis-free and cancer-specific survival rates at 5 years after treatment. Although longer term follow-up of RFA will be required to determine late recurrence rates, the current results indicated a minimal risk of disease recurrence in patients who are >3 years removed from RFA. Cancer 2010;116:3135-42. (C) 2010 American Cancer Society.