BOSTON (CBS) — Senator John McCain was diagnosed with the same type of cancer that killed Senator Ted Kennedy. Dr. Mallika Marshall spoke to a one of the oncologists who treated Senator Kennedy about this deadly form of cancer.

Glioblastoma multiforme is rare yet it is the most common type of cancer arising in the brain. It is aggressive and fast growing and while it doesn’t spread to other areas of the body, it ravages the brain itself.

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“It can infiltrate and spread into the adjacent brain very efficiently and very effectively and as it grows and spreads outwards, it can cause dysfunction and difficulty of the nerves in the brain,” explains Dr. David Reardon, a neuro-oncologist at the Dana Farber Cancer Institute who treated Senator Ted Kennedy for the same type of tumor.

Dana Farber Cancer Institute’s Dr. David Reardon who helped treat Ted Kennedy’s brain cancer (WBZ-TV)

Dr. Reardon says glioblastomas are challenging for several reasons. They are located in a vital organ, the brain, making surgery difficult. The brain is protected by the blood-brain barrier making it hard for chemotherapy and other therapies to penetrate. Treatments that may initially work often eventually fail.

“Some of the tumor cells are able to persevere, mutate, and adapt and become resistant,” says Dr. Reardon. “So the durability of the treatment, unfortunately, for most patients is not long-lasting.”

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While the median survival is only 15 to 18 months, new innovations and treatments are showing promise for a small percentage of patients.

“We do have a growing number of patients who are 3-years or 5-years or even 5 to 10 years who are doing well without tumor recurrence,” says Dr. Reardon.

Dr. Reardon says the favorable location of Senator McCain’s tumor, his overall good health, and his fortitude should serve him well and help him get back to the government work he holds so dear.

“I certainly expect,” says he says, “Particularly knowing how Senator McCain is and his commitment and physical status that he’ll be very keen to push forward and continue these activities that are so important to him.”

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It is likely that once he has recovered from brain surgery, Senator McCain will undergo radiation and chemotherapy, and Dr. Reardon says the Dana Farber has been contacted to see if they might be able to help in some way with the senator’s care.

Dr. Mallika Marshall