Patients who develop the most common kind of primary malignant brain tumor are sometimes given drugs they may not need and deprived of others that might help, medical researchers said on Tuesday.

Primary brain tumors are those that originate in the brain, rather than being spread there by cancer elsewhere in the body. Survival rates for those diagnosed with the more serious forms of the tumors, malignant glioma, run three to five years to as little as one year in the worst cases.

Researchers at the University of California in San Francisco said a look at 788 adult patients treated at 52 U.S. and Canadian sites from 1997 to 2000 found that treatment varied greatly and was sometimes in conflict with guidelines.

Their study said the use of diagnostic tools and treatments such as magnetic resonance imaging, radiation and surgery were consistent.

But it also found that fewer than 70 percent of patients were given chemotherapy, even though research indicates it is useful for brain tumors. In addition 89 percent in the study were given anticonvulsant drugs, even though only 31 percent had problems with seizures.

“While it is accepted that patients who present with seizures should receive anti-epileptic drugs, there is strong evidence that prophylactic (uses) have little value for seizure-free patients with newly diagnosed brain tumors,” the report said.

Such drugs “are associated with significant side effects” and should be discontinued the first week after surgery if no seizure problems develop, it added.

“Our goal in neuro-oncology is to improve the duration and quality of survival of our patients,” said Susan Chang, a physician at the school who led the research.

Brain tumor specialists need to communicate with each other but also should collaborate with “other health care providers, including emergency physicians, primary physicians, neurologists and oncologists…so that the optimum care is provided,” she said.

The report, appearing in this week’s issue of The Journal of the American Medical Association, was supported in part by grants from Aventis Pharma Ltd., part of Sanofi-Aventis, and Guilford Pharmaceuticals Inc., as well as the National Institutes of Health.