Radiofrequency Ablation of Brain Tumors New Option

CHICAGO--A new minimally invasive procedure for treating certaintypes of primary or metastatic brain cancer offers an alternativeto patients who are too ill to undergo standard craniotomy, chemotherapy,or radiotherapy, or who have not responded to these conventionaltherapies.

Yoshimi Anzai, MD, and Robert Lufkin, MD, reported on their research,performed at the UCLA School of Medicine, at the annual meetingof the Radiological Society of North America (RSNA).

The procedure uses a radiofrequency probe that is directed tothe site of the brain tumor and is heated to 80°C for 1 minuteto destroy the cancerous tissue. The probe is encased within acatheter that is inserted through a small incision in the skull.Proper insertion of the probe is guided by a stereotactic frameplaced over the patient's head.

The probe is placed at the tumor site with the assistance of aninterventional magnetic resonance (MR) machine. This machine hasan open structure that allows the physician to stand next to thepatient while positioning the probe. The physician follows themovement of the probe in the brain on a video monitor.

"MR imaging provides a clear picture of the tumors duringthe treatment and also has the advantage of giving us immediatefeedback about the effect of the treatment on the tumor,"said Dr. Anzai, formerly an assistant professor at UCLA and nowwith the University of Michigan. MR imaging follow-up also tracksthe decline in tumor volume after treatment or provides evidenceof recurrence.

To date, MR-guided stereotactic radiofrequency ablation has beenused to treat 18 brain tumors in 15 patients, Dr. Anzai said.Preliminary results show that the procedure accomplished localcontrol of 10 tumors over a follow-up period ranging from 4 to20 months. Although eight tumors recurred in six patients, mostrecurrences involved metastatic melanoma or renal cell carcinoma.These forms of brain cancer are not suitable for radiofrequencyablation because they are highly vascular, she noted.

Dr. Anzai believes that the MR guided treatment may reduce costsand improve the quality of life of patients with often debilitatingbrain cancer. She cited several other possible advantages of thisnew procedure:

The delivery of the radiofrequency energy is highly focused sothat nearby, healthy brain tissue is not affected.

Because only local anesthesia is required, physicians can monitorneurologic function throughout the procedure by asking patientsto perform simple movements or express sensations.

The procedure requires only 3 hours in the operating room and24 hours of postoperative inhospital observation.

It can be done on patients who received previous, unsuccessfultreatment, and can be repeated if tumors recur.