Doctors performed a biopsy on U.S. Senator Edward Kennedy and announced Tuesday that they found a malignant brain tumor. The Democrat and elder statesman of American liberal politics suffered a siezure last Saturday morning at his home in Massachusetts. VOA's Carol Pearson reports on this type of cancer.

Senator Edward Kennedy's doctors found a tumor in tissue that supports the nerve structure in the brain and spinal cord. The term for it is malignant glioma. And one of the common symptoms is a seizure.

Senator Kennedy was rushed to the hospital after having one. The National Cancer Institute says malignant gliomas are the most common type of brain cancer among adults.

No one knows the cause of brain tumors but there are several risk factors: Men are more likely to get them than women. And they occur more often in whites than in people of other races. Age is also a factor. They are more likely to be diagnosed in people 70 years old or older.

Brain tumors can be diagnosed by several means including a C-T scan or an MRI or a biopsy. They can be challenging to treat, but new technology can help.

At Duke University Medical Center in [the southeast state of] North Carolina, doctors perform precise radiosurgery on tumors with a machine called the Novalis Tx.

Dr. John Kirkpatrick says the technology is almost like magic, "We can deliver a higher dose to tumors which means we can get better control of the tumor and at the same time, avoid the normal structures in the body."

Senator Kennedy's doctors are still determining the best course of treatment for him.

But the U.S. National Cancer Institute says the outlook for patients with malignant gliomas is poor.

Still, it recommends surgery for all operable brain tumors followed by radiation or chemotherapy.