WASHINGTON - A malignant glioma - the diagnosis doctors gave Sen. Edward M. Kennedy - is the worst kind of brain cancer.

Malignant gliomas strike almost 9,000 Americans a year. Survival statistics are grim - few live three years and, for the worst subtype, half die within a year.

Who lasts longer - and some do - depends on exactly what form of glioma someone has, whether surgeons can cut most of it out, age and some other medical details.

Kennedy's doctors didn't mention surgery, suggesting that that may not be a possibility for him.

"As a general rule, at 76, without the ability to do a surgical resection, as kind of a ballpark figure you're probably looking at a survival of less than a year," said Dr. Keith Black, chairman of neurosurgery at Cedars-Sinai Medical Center in Los Angeles.

On the plus side, scientists are studying new approaches - adding a drug called Avastin to standard treatment, or even brewing up customized vaccines to help the body fight back. Although those approaches are still experimental, glioma experts advise newly diagnosed patients to seek out specialized cancer centers and to ask if they're a good candidate for a research study up front.

"Considering how poorly they do despite standard treatment, it is always best to seek a clinical trial," said Dr. Deepa Subramaniam, director of the brain-tumor center at Georgetown University's Lombardi Comprehensive Cancer Center. "They are not likely to do worse."

Kennedy was hospitalized Saturday after a seizure. Yesterday, doctors at Massachusetts General Hospital announced the reason: a malignant glioma in his left parietal lobe, a brain region that governs sensation but also plays some role in movement and language. Doctors were awaiting further tests before choosing treatment, but they cited radiation and chemotherapy as the usual approach.

Kennedy's age and the mention of upfront chemotherapy mean the glioma is almost certainly one of the two worst forms: a glioblastoma - the fastest-killing brain tumor, known for claiming entertainer Ethel Merman and Republican political strategist Lee Atwater - or the only somewhat less aggressive anaplastic astrocytoma, Subramaniam said. *