CHICAGO--A new minimally invasive procedure for treating certain types of primary or metastatic brain cancer offers an alternative to patients who are too ill to undergo standard craniotomy, chemotherapy, or radiotherapy, or who have not responded to these conventional therapies.
Yoshimi Anzai, MD, and Robert Lufkin, MD, reported on their research, performed at the UCLA School of Medicine, at the annual meeting of the Radiological Society of North America (RSNA).
The procedure uses a radiofrequency probe that is directed to the site of the brain tumor and is heated to 80°C for 1 minute to destroy the cancerous tissue. The probe is encased within a catheter that is inserted through a small incision in the skull. Proper insertion of the probe is guided by a stereotactic frame placed over the patient's head.
The probe is placed at the tumor site with the assistance of an interventional magnetic resonance (MR) machine. This machine has an open structure that allows the physician to stand next to the patient while positioning the probe. The physician follows the movement of the probe in the brain on a video monitor.
"MR imaging provides a clear picture of the tumors during the treatment and also has the advantage of giving us immediate feedback about the effect of the treatment on the tumor," said Dr. Anzai, formerly an assistant professor at UCLA and now with the University of Michigan. MR imaging follow-up also tracks the decline in tumor volume after treatment or provides evidence of recurrence.
To date, MR-guided stereotactic radiofrequency ablation has been used to treat 18 brain tumors in 15 patients, Dr. Anzai said. Preliminary results show that the procedure accomplished local control of 10 tumors over a follow-up period ranging from 4 to 20 months. Although eight tumors recurred in six patients, most recurrences involved metastatic melanoma or renal cell carcinoma. These forms of brain cancer are not suitable for radiofrequency ablation because they are highly vascular, she noted.
Dr. Anzai believes that the MR guided treatment may reduce costs and improve the quality of life of patients with often debilitating brain cancer. She cited several other possible advantages of this new procedure: