By Brenda Tilke

Radio-frequency (RF) ablation of liver tumors has gained considerable interest from oncologists and interventional radiologists, but the technique also shows promise in treating extrahepatic tumors, according to a scientific presentation at the RSNA meeting. The presentation earned the magna cum laude award.

A team from the diagnostic imaging department at Brown University and Rhode Island Hospital showed the results of RF ablation of a variety of nonhepatic tumors. The interventional radiologists used CT, MR, and ultrasound for image guidance, with CT the most common choice. The group has used RF ablation to reduce pain and provide a treatment alternative when surgery, chemotherapy, and radiation therapy are contraindicated. They were able to create heat lesions as large as 7 cm with a single treatment, overcoming the previous size limitations of extrahepatic RF ablation.

For the treatments, the team used a thin (21 to 14-gauge) RF electrode, which was placed directly into the tumor. The attached generator produced a current that was emitted from the exposed noninsulated portion of the electrode. Radiowave frequency ranged from 460 to 480 kHz. Friction converted into heat caused cellular death in the tumor sites.

Among the tumors treated were osteoid osteomas, painful bone lesions that usually occur in children. Unlike conventional surgery treatment, the RF procedure requires no inpatient stay and can be done with conscious sedation, although general anesthesia may be needed for some patients.

The technique may be particularly useful for metastatic bone cancer, which affects up to 70% of cancer patients and can cause debilitating pain. The team had success in reducing tumor size and providing substantial pain relief.

Solid lung tumors have also shown positive response to the treatment. A single application can treat a tumor as large as 5 cm, and may be useful for patients with inoperable lung cancer, the team reported.