The type of brain tumor that Sen. Edward M. Kennedy has — a glioma — originates in the brain and accounts for 77 percent of malignant brain tumors and 42 percent of all brain tumors, medical experts said yesterday.
Mr. Kennedy, Massachusetts Democrat, has a malignant glioma in the left parietal lobe, according to a statement from his doctors at Massachusetts General Hospital.
Doctors first look at tumor location and size in determining the role of surgery, said Dr. Mike Edgeworth, assistant professor of neurology, division of neuro-oncology at Vanderbilt University Medical Center. Surgery is the first line of treatment against gliomas.
One of the biggest problems is that gliomas have roots or tentacles, making it impossible to remove them completely by surgery, said Dr. Gail Rosseau, a neurosurgeon with CINN Medical Group in Chicago and a spokeswoman for the American Association of Neurological Surgeons.
It can’t be removed in total, surgically, the way some other types of tumors can be, she said.
Treatment typically involves surgery, followed by a combination of radiation and chemotherapy, the doctors said. The most common chemo agent for a malignant glioma is temozolomide, an oral medication, Dr. Edgeworth said.
Several types of gliomas vary in aggressiveness; with limited information about Mr. Kennedy‘s, it would be inappropriate to speculate on his prognosis, said Dr. Otis W. Brawley, chief medical officer for the American Cancer Society.
He and other cancer experts said prognosis is determined by considering the types of cells in the brain tumor, how fast they are growing and the patient’s age, since survival rates drop with increasing age. Mr. Kennedy is 76.
Dr. Edgeworth said a malignant glioma is usually labeled as a grade 3 or 4, meaning the most serious and deadly. Median survival rates for a grade 2 glioma is about seven to nine years, for grade 3 about two to three years, and for grade 4 about 12 to 15 months, he said.
The grade of a tumor is determined by looking at the pathology of its cells under a microscope, he said.
Doctors at Massachusetts General didn’t disclose the grade of Mr. Kennedy’s tumor or specific type of glioma yesterday even though they said they did a biopsy.