New Study Offers Hope To Cancer Patients
PORTLAND, Ore., July 7, 1998 -- Reporting in the July issue of the Journal of Pharmacology and Experimental Therapeutics, researchers with the Portland U.S. Department of Veterans Affairs Medical Center and Oregon Health Sciences University have found that they can prevent or sharply reduce hearing loss caused by one of the most effective therapies for brain tumors.
The VA/OHSU team found that treatment with sodium thiosulfate (STS) significantly reduced hearing loss in 29 brain tumor patients receiving the chemotherapy agent carboplatin delivered by opening the blood-brain barrier.
"These findings are very encouraging," said study leader Edward A. Neuwelt, M.D., a neurosurgeon and professor of neurology and neurosurgery at the Portland VA Medical Center and OHSU. He also directs the Blood-Brain Barrier Program located at both the VA and OHSU.
"Not only did we see fewer patients suffer severe hearing loss, but patients who did experience some hearing loss were able to undergo more courses of carboplatin treatment before any loss occurred."
Before the STS trials began, 15 (79 percent) of 19 similar patients suffered profound hearing loss caused by carboplatin treatment. These patients had an average hearing loss of 20.8 decibels after one treatment with carboplatin, while the STS-treated patients lost only 3.7 decibels.
The Portland researchers previously had paved the way for brain tumor treatment with carboplatin and similar agents by pioneering methods to open the "blood-brain barrier" in order to enhance drug delivery (Neurosurgery, May 1998). This natural barrier normally serves as a wall between the blood and brain, helping protect brain tissue.However, it also prevents large-molecule drugs such as carboplatin from reaching a tumor inside the brain.