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Stanford Report, November 14, 2001

New device delivers safer, targeted brain tumor treatment straight to the source

By MICHELLE BRANDT

A medical center neurosurgeon is one of the first in the country to use on brain tumors a new device for aggressive intratumoral radiation – radiation therapy that irradiates cancerous cells from within the tumor cavity. Griff Harsh, MD, professor of neurosurgery at Stanford, has successfully treated two patients with the GliaSite technique, a method of targeted and accelerated delivery of intratumoral radiation. Stanford is the only hospital on the West Coast to use the device.

"This technique is an important new treatment option for patients with malignant brain tumors," said Harsh, who is also director of the Stanford Brain Tumor Center. "Radiation combined with surgery is the single most effective way to treat brain tumors, and intratumoral radiation is a highly advantageous way of delivering additional radiation to the site of the cancer."

According to the American Cancer Society, more than 16,000 Americans are diagnosed with malignant primary brain tumors each year, and Harsh said the majority of patients are treated with a combination of surgery and external beam radiation therapy. With typical treatment, external beams of x-rays are sent from outside the body to the tumor cavity – passing through healthy brain tissue. Traditional radiation therapy, which usually lasts six weeks, suppresses tumor regrowth for a period of time – but almost all patients experience recurrences.

Unlike older approaches, GliaSite delivers an even, easily controlled dose of radiation to the targeted tumor area while minimizing exposure of nearby healthy brain tissue. The technique requires surgically removing the brain tumor and inserting an expandable balloon into the tumor cavity. The balloon is connected by a thin catheter to a small reservoir placed just beneath the patient's scalp. After one to two weeks, the balloon is filled with a liquid source of radiation. Over a course of three to seven days, high doses of radiation are delivered through the balloon directly to the tissue surrounding the cavity. The balloon, catheter, reservoir and liquid radiation are then removed.

Stanford Hospital's first GliaSite patient, a 31-year-old San Jose, Calif., resident with a recurring tumor, began his treatment last month. The therapy was recently completed and the patient, who left the hospital the day his catheter was removed, experienced no ill effects and said he "feels great."

Harsh said a short recovery time and the low incidence of side effects are benefits. "Preliminary studies have suggested that the risk of harmful side effects such as radiation necrosis" – damage to surrounding tissue – "is markedly lower with this technique than with alternatives," he said.

In the past, patients with recurring brain tumors have had few treatment options. A second course of traditional radiation typically isn't advised for a recurring tumor.

The reliability of the new device, which was recently approved by the FDA, was demonstrated in a recent National Cancer Institute-sponsored study of patients with recurring primary brain tumors.

Harsh said the Stanford Brain Tumor Center plans to use this technique in patients with newly diagnosed or recurring primary or metastatic brain tumors.



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