Kathleen[a]
Thursday, 09/26/02
Catheter offers more direct treatment of brain cancer
By JACK HURST
Staff Writer
Woman is Nashville´s first recipient
Franklin homemaker Pam Hillis noticed a couple of months ago that her hand was suddenly "a little uncoordinated" and went to her doctor.
Within hours, Hillis was diagnosed with a brain tumor. The cancer soon was removed and, at Saint Thomas Hospital this week, Hillis became the Nashville area´s first recipient of a new treatment to try to prevent it from returning. In a small balloon placed temporarily inside the skull, liquid radiation was injected into the site from which the tumor was taken.
"My husband, who is a research scientist himself, asked a lot of questions," Hillis said yesterday in her hospital room, where she wore a lead-lined cap to protect visitors against radiation. "It made a lot of sense to us that the balloon would fit perfectly into where they lifted the tumor out of."
The reason for this kind of treatment - via a GliaSite RTS balloon-catheter system - is to get a "boost" of treatment at the site of the tumor, which is where most brain cancers recur, said Dr. Steven Abram, the surgeon.
This technique does not replace external radiation treatment for brain tumors, he added, but only so much external radiation can be applied without adversely affecting the rest of the brain. The GliaSite method allows more radiation to reach the cancer site, and the hope is that it will enable less radiation to be used, making for fewer "life-altering" side effects including loss of cognitive skills.
"The excitement for us is to give the patients a better quality of life and hope that we can extend quantity of life," he said. "We´re entering an era now where we´re just starting to talk about lengthening patients´ lives and not just palliation of the quality of their remaining lives."
Abram said preliminary indications are that the balloon-catheter technique can extend a life from months to more than a year.
The GliaSite treatment "makes sense," said Hillis´ radiation oncologist Dr. Thomas Hunter, because the balloon conforms to the size of the tumor area and carries radiation to it only. He said that in the only study he has seen, the method reduced the recurrence of cancer in the immediate area of a removed tumor from 80% to 20%.
"This is a very smooth, even, uniform irradiation around that catheter, so it appears that this offers us a substantial advantage," Hunter said. "We´re not looking at ultimate cure, but we´re looking at significant prolongation of useful, functional time."
In treating Hillis, Abram said, doctors first had to take out the tumor, then measure the area from which it was removed and tailor the size of the catheter balloon to that area.
Then Hunter devised a treatment plan based on how far the physicians wanted to penetrate with radiation into the wall of the tumor area. They were able to "very precisely regulate" the amount of radiation contacting the "wall" of that area, Abram said.
After that, they reverted to their traditional surgical technique, closing the brain lining and replacing the skull bone, at the same time bringing one end of the catheter out and coiling it on top of the skull bone. When the scalp was closed, they were able to feel the "access port" at the other end of the balloon system.
This week, Abram and Hunter brought Hillis back into the hospital and, with a needle that Hillis described as uncomfortable, filled the balloon with the amount of radioactive liquid that they had calculated was needed.
The liquid is left there from three to seven days, depending on the situation. Abram said Hillis will have it for five.
Then the exact amount of liquid that was injected will be taken back out, the catheter removed and the patient discharged the next day.
Abram and Hunter said that about 200 balloon catheters have been implanted in a number of academic medical centers in a technique that was approved by the U.S. Food and Drug Administration last year. They described it as very safe, both for patients and medical personnel.
Hunter said a liquid chemical known as Iotrex contains the radiation that is conducted to the tumor site.
If, by some accident, it is released into the rest of the body, it would not be absorbed.
"Normally, it would be absorbed everywhere, but because of the nature of the Iotrex solution, it would simply be cleared through the kidneys and you´d get rid of it."
Iotrex was developed by researchers working in the same department with Hillis´ husband when he worked for Dow Chemical, she recalled yesterday. He now is a marketing executive with another company.
According to information from Proxima Therapeutics Inc. of Atlanta, the firm that patented the GliaSite system, patients who received the treatment had an average survival rate of 387 days and a 52% survival rate after a year.
Abram said any criticism of this new tactic against brain tumors is perhaps in the question of whether the additional "months or maybe a year" is worthwhile.
"If it´s a matter of being able to go through a life event with a family member, or being able to come to grips with the diagnosis and a family´s interaction, then I think those are potentially incredibly valuable months."