Heat Zapps Bone Tumors

The results of the study, published in the March issue of the Journal of Vascular Interventional Radiology, suggests a need for further research to confirm the effectiveness of percutaneous radiofrequency for treating osteoid osteomas.

In the study, all eight patients achieved complete pain relief after thin probes were inserted through the skin into the core of the bone tumor, and radiofrequency energy was used to produce enough heat to destroy the tumor at its biological core. Five patients underwent the procedure with guidance provided by a new type of fast CT scanner incorporating CT fluoroscopy at 13 frames a second in three places at once.

Osteoid osteomas account for up to 12 percent of all benign bone tumors and occur primarily in children and young adults, according to Kieran Murphy, M.D., director of neurointerventional radiology at Hopkins and a member of the study team. While not life-threatening, the tumors can be extremely painful.

Standard treatment consists of nonsteroidal anti-inflammatory drugs. However, when pain is severe and/or long-term conventional drug treatment causes complications, surgical removal is the usual alternative.

Murphy notes that while the reported success rate for such surgery is very high, it carries some risks. "Depending on the size of the bone tumor, bone fractures can occur at the site of the tumor removal and bone grafting may be required," he says.

While all eight of the patients benefitted, three achieved success only after re-treatment. Initial failures were attributed to the use of fluoroscopy alone for tumor localization, which provided less precise tumor images than did CT fluoroscopy. One patient eventually required surgical removal of the tumor to achieve complete pain relief. No immediate or delayed complications were observed in any of the patients treated.

"Based on these early results, it appears that CT fluoroscopy offers the most precise imaging method for localizing the most critical area of the tumor in which to place the heat probe," says Murphy. "Combining the minimally invasive approach of radiofrequency ablation and the enhanced imaging guidance of CT fluoroscopy gives us a potentially powerful new alternative for treating these tumors."