The uncertainty of radio frequency treatment of renal cell carcinoma: findings at immediate and delayed nephrectomy.

PURPOSE Radio frequency thermal therapy for the ablation of renal cell carcinoma has been reported. Outcomes are usually measured by imaging alone. We have performed ex vivo and in vivo experiments using radio frequency in porcine models in our laboratory. We now report our early experience in the treatment of renal cell carcinoma in patients who underwent post-radio frequency radical or partial nephrectomy. MATERIALS AND METHODS We treated 10 patients diagnosed with small renal masses with radio frequency. All masses were biopsied before treatment. In 4 patients 5 renal cell carcinomas were treated with radio frequency after surgical exposure of the tumor followed immediately by partial or radical nephrectomy (acute group). Six other patients were treated percutaneously with ultrasound or computerized tomography guided radio frequency under local anesthesia and intravenous sedation 7 days before partial or radical nephrectomy (delayed group). A median of 2 radio frequency cycles was applied. Mean total heating time was 17 minutes 15 seconds. Specimens were analyzed grossly and histologically. Triphasic contrast-enhanced computerized tomography and/or magnetic resonance imaging was performed before and 7 days after radio frequency treatment in the delayed group. RESULTS Mean radiological largest diameter of all 11 masses was 2.4 cm. and mean gross diameter was 2.2 cm. Pathological examination demonstrated residual viable tumor in approximately 5% of the volume in 4 of the 5 tumors in the acute group and in 3 of the 6 masses of the delayed group. In 1 delayed case the viable tumor appeared to be in contact with the renal vein. No significant complications were observed in 9 of the 10 patients. In 1 delayed case, a subcapsular hepatic hematoma, biliary fistula and pneumonia developed and resolved. CONCLUSIONS Based on our experience, we continue to consider percutaneous radio frequency for the treatment of small renal cell carcinomas as a potentially curative therapy. However, complete tumor cell death appears to be difficult to achieve with our current treatment protocol. More phase II testing is indicated to ensure that this technique is an effective and reproducible treatment alternative.