Kennedy's Brain Cancer: How Bad?

  • Share
  • Read Later
Evan Vucci / AP

Senator Edward Kennedy

Sen. Ted Kennedy's seizure on Saturday has now been diagnosed as the result of a cancerous brain tumor. But his prognosis will depend on what doctors at Massachusetts General Hospital find as they continue their tests and weigh treatment options.

A biopsy of a suspicious growth in the 76-year-old senator's left parietal lobe revealed a malignant glioma, the most common type of brain tumor. It is diagnosed in some 25,000 Americans a year, and in 30% to 40% of cases, the first sign of the disease is a seizure — as was the case with Kennedy, who has been hospitalized since the weekend, but has not suffered another seizure. "Decisions regarding the best course of treatment for Senator Kennedy will be determined after further testing analysis," the senator's doctors said Tuesday in a statement. "He remains in good spirits and full of energy."

Kennedy's prognosis depends on several factors. Most critical is the type of glioma. Glioblastomas are the most aggressive and common type, and only 3% of patients diagnosed with these tumors generally survive five years after diagnosis. Patients with slower-growing tumors have a 25% chance of surviving to five years. It's not clear yet what kind of tumor the senator has, or which treatment option he will follow — the standard therapy for glioma usually involves surgery to remove the malignant lesion, followed by chemotherapy and radiation.

Two new chemotherapy agents that Kennedy and his doctors will most likely consider are Temodar, an oral drug, and Gliadel, a wafer embedded with a cancer-killing drug that surgeons place in the brain after the tumor is removed. The wafer dissolves over a period of two weeks and, if successful, destroys any remaining cancer cells in its wake. Radiation therapy for glioma usually begins two weeks following surgery, and lasts for about six weeks, says Dr. Henry Brem, director of neurosurgery at Johns Hopkins Hospital, who helped develop Gliadel and is not involved in Kennedy's treatment.

Treatment of glioma can be difficult, say researchers, because they still don't know what causes the disease. The cancer arises from glial cells, which outnumber neurons 10 to 1, and whose function is to support the electrical activity of neurons in the brain — but doctors don't know what pushes normal glial cells to become cancerous in the first place. "We know very little about the biology of malignant glioma," says Dr. Azad Bonni, a professor of pathology at Harvard Medical School who is investigating some of the molecular explanations behind the disease.

"There is a lot of work being done on which genes are associated with these tumors, but as of now, we have no real understanding of what triggers someone to have a glioma," says Brem.

Depending on where the senator's tumor is located, Kennedy could expect to return to near-normal functioning. If the lesion is in a location where surgeons can remove it easily, then he has a good chance of controlling the cancer with additional chemotherapy and radiation. "I have patients 20 and 30 years out from diagnosis, and they are functioning normally and doing well," says Brem. "We hope that Senator Kennedy becomes one of them."