RF ablation shows efficacy for small renal tumors

March 1, 2005

The intermediate results are encouraging for the oncologic efficacy of radiofrequency ablation.

Mumbai, India-Radiofrequency ablation appears to be a safe, efficacious procedure for the treatment of small renal tumors, according to results from two separate studies presented at the World Congress on Endourology here.

In the first study, researchers from the University of Texas Southwestern Medical Center, Dallas, found that RF ablation was safe and provided adequate cancer control in properly selected patients.

The retrospective study examined 92 patients with 115 tumors, said J. Kyle An-derson, MD, an endourology fellow at UT Southwestern working with Jeffrey Cadeddu, MD, and colleagues. Sixty-nine patients underwent percutaneous RF ablation using the FDA-approved RITA (Sigmacon, North York, Ontario), and 46 had RF ablation via a laparoscopic approach. All patients were treated with a new RF generator with one to three cycles of 3 to 10 minutes depending on the size of the renal tumor.

2.6% rate of metastasis Out of the 39 patients with more than 1-year follow-up, two patients developed metastasis. The patient with lung metastasis was one of them, and the second one was essentially excluded from the series, as surgeons performed RF ablation on a recurrence of her renal tumor, not the primary lesion. She had previous surgery for her original lesions.

Thus, the researchers had a 2.6% (one of 39) rate of metastasis in patients with more than 1-year follow-up. The patient had one major complication related to the procedure, which led to nephrectomy.

"Appropriate imaging studies to confirm ablation success are a significant component of this therapy. Given appropriate radiologic follow-up, intermediate results for radiofrequency ablation suggest that this will be a viable treatment option for small renal tumors," Dr. Anderson said.

In summary, the intermediate results are encouraging for the oncologic efficacy of radiofrequency ablation, Dr. Anderson said. In order to achieve good results, diligent follow-up imaging is ex-tremely important, as incomplete ablations can occur in a small percentage of patients, and these incomplete ablations can be successfully managed with re-ablation. However, he added that longer follow-up is necessary to confirm the procedure's durability and safety.

RF ablation, cryo compared The second study compared two minimally ablative techniques-RF ablation and cryoablation-for the management of small, asymptomatic renal tumors, primarily in patients with significant comorbidities. Kenneth Ogan, MD, assistant professor of urology at Emory University, Atlanta, presented the retrospective study, which looked at 35 patients (19 undergoing RF ablation and 16 cryoablation) over 32 months. Mean tumor size among the RF ablation and cryoablation groups were 2.76 cm and 2.54 cm for the RF ablation and cryoablation groups, respectively. Average follow-up-8.2 months for RF and 10.2 months for cryoablation-were similar.

Tumor ablation was successful in 87% of tumors treated with RF ablation compared with 83% of those treated with cryo-therapy. The recurrence rates were similar for the two procedures, except patients who received cryotherapy had a 19% rate of transfusion and skin injury.

The take-home message from his study is that while both RF ablation and cryoablation are safe and efficacious for select group of renal tumors, neither was found to be superior in the Emory group's experience, Dr. Ogan said. He added that longer follow-up is necessary to determine the oncological effectiveness.

Audience member Vlad Bargman, MD, a fellow in endourology at Indiana University, said that he thought that cryotherapy showed superior outcomes to those of RF ablation, but this study shows both are similar, at least in the short term. He agreed that term follow-up is mandatory before drawing any comparisons and conclusions.