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: