The study published in the journal Hearing Research found that rats treated with N-acetylcysteine, or NAC, did not suffer from platinum-induced ototoxicity, or hearing loss, caused by a widely used chemotherapeutic agent known as cisplatin.
Cisplatin, or CDDP, is a platinum-based compound used in chemotherapy for head and neck cancer. But it causes progressive, irreversible hearing loss, reducing patients' quality of life and forcing doctors to use lower, less-effective doses of the drug.
"It affects about a third of all children with cancer in the United States, not just those with brain tumors," said study co-author Edward Neuwelt, M.D., professor of neurology and neurological surgery, OHSU School of Medicine, and the Portland Veterans Affairs Medical Center. He also directs OHSU's Blood-Brain Barrier Program. "It's a big problem."
The study's lead author, D. Thomas Dickey, D.V.M., research instructor in neurology, OHSU School of Medicine, called ototoxicity "one of the main dose-limiting factors in giving cisplatin."
"Cisplatin is given a lot. It's been around a long time, and it's very effective. But it's very toxic," Dickey said.
Cisplatin is administered intravenously to slow or stop the growth of cancer cells. In addition to head and neck cancers, the drug is used to treat cervical carcinoma, lung cancer, neurologic cancers and a wide variety of other malignancies. But it injures hair cells of the cochlea, the spiral, inner-ear structure containing thousands of tiny hair cells that vibrate in response to sound waves.
"These hair cells are often destroyed," Dickey said. "It starts at the outer edge and moves in. Once it happens, it's progressive -- it gets worse and worse -- and it's permanent."
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Contact: Jonathan Modie
modiej@ohsu.edu
503-494-8231
Oregon Health & Science University
20-Jul-2004