Massachusetts General Hospital (MGH) researchers have shown that radiofrequency ablation (RFA) - a minimally invasive way of destroying tissue - is an effective, longlasting treatment for small kidney tumors in selected patients. In a followup to research published in 2003, the investigators found that RFA treatment of renal cell carcinoma, the most common kidney cancer, continued to be successful 4 to 6 years after administration.
The report appears in the July issue of the Journal of Urology.
"This study shows, for the first time, that this is a very effective long-term treatment," says W. Scott McDougal, MD, chief of Urology at MGH and lead author of the study. Renal cell carcinoma will be diagnosed in almost 32,000 Americans this year and is most frequently treated with surgical removal through either an open or laparoscopic procedure.
RFA delivers heat generated by electrical energy to sites within the body through a thin needle, similar to probes used in biopsy procedures. Placement of the probe is guided by CT scan, ultrasound or other imaging techniques. Widely used to treat cardiac arrhythmias, RFA is also being investigated for destruction of small liver tumors and has been used for more than ten years to treat a benign bone tumor called osteoid osteoma.
For more than six years MGH physicians have been using RFA to treat kidney tumors in patients for whom surgical removal was not an option because of other health concerns. For the current study, the research team reviewed information on 16 of the first patients treated with the technique; three patients had multiple tumors, making a total of 20 tumors treated.
In the four years following their treatment, five patients whose treatment was initially successful died from causes unrelated to kidney cancer. Of the 11 remaining patients, none had any recurrence or metastasis of the kidney tumor 4 to 6 years after treatment. Overall, treatment of all tumors on the surface of the kidney was successful, as was the treatment of tumors deep within the kidney, which sometimes requires additional treatments. Two patients had what are called mixed tumors, and only one of them was treated successfully. Although treatment of the other mixed-tumor patient did not reduce the size of the lesion, that patient died of an unrelated brain tumor a year after treatment.
McDougal adds that the MGH team now has used RFA to treat a total of 100 renal cell carcinomas in 85 patients with similar results - successful tumor destruction in 100 percent of surface tumors and 78 percent of central tumors. "Right now, older patients with small lesions in limited areas of their kidneys are good candidates for this procedure. We need to wait for 10-year followup information to determine whether it will be appropriate for patients with a longer life expectancy." McDougal is the Walter S. Kerr, Jr. Professor of Urology at Harvard Medical School.
The report's co-authors are Francis McGovern, MD, MGH Urology, and Debra Gervais, MD, and Peter R. Mueller, MD, of the MGH Department of Radiology.