Sen. Edward M. Kennedy was admitted to Duke University Medical Center on Monday for a risky six-hour surgery for his cancerous brain tumor.

A statement from the Massachusetts Democrat's office said the surgery would be performed by one of the nation's top neurosurgeons, Dr. Allan Friedman.

Kennedy, 76, faces chemotherapy and radiation treatment following the procedure.

Sen. Kennedy was diagnosed last month with a malignant glioma, a lethal type of brain tumor.

Experts said surgeons will likely try to remove as much of the tumor as possible while balancing the risk of harming healthy brain tissue that affects movement and speech.

"Almost no malignant gliomas are cured by surgery, but many of us believe that the more you get out, the next treatments, whether they be radiation or chemotherapy, have a better chance of working because there's less tumor there to fight," said Dr. Matthew Ewend, neurosurgery chief at the University of North Carolina, Chapel Hill.

The surgery was scheduled to begin around 9 a.m., said Anthony Coley, a Kennedy spokesman.

The senator was expected to remain at the North Carolina facility for one week to recuperate and then will begin further treatments at Massachusetts General Hospital and start chemotherapy.

Typical radiation treatment is five days a week for a month, using 3-D imaging techniques that narrowly deliver the beams to the tumor, affecting as little surrounding tissue as possible.

 

Kennedy said in a statement that over the past few days he and his wife, Vicki, "along with my outstanding team of doctors at Massachusetts General Hospital, have consulted with experts from around the country and have decided that the best course of action for my brain tumor is targeted surgery followed by chemotherapy and radiation."

"I am deeply grateful to the people of Massachusetts and to my friends, colleagues and so many others across the country and around the world who have expressed their support and good wishes as I tackle this new and unexpected health challenge," Kennedy said. "I am humbled by the outpouring and am strengthened by your prayers and kindness."

After his treatment, Kennedy said, "I look forward to returning to the United States Senate and to doing everything I can to help elect Barack Obama as our next president."

Kennedy has endorsed Obama, the front-runner for the Democratic presidential nomination.