Carroll County Times
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What is glioblastoma? Cancer that killed John McCain aggressive, difficult to treat

In July 2017, Sen. John McCain, R-Arizona, was diagnosed with glioblastoma, an aggressive form of brain cancer. A little over a year later, on Aug. 25, McCain had succumbed the disease.

That is, unfortunately, according to Dr. Roberto Martinez, an oncologist at the Alvin and Lois Lapidus Cancer Institute at LifeBridge Health, a common course for those diagnosed with this disease.


“Average survival is about one year,” he said. “There is a tail to the survival curve, so there are some lucky people who live longer; there is five-year survival of 5 to 10 percent, so those 5 percent of people may live up to five years.”

The National Cancer Institute estimates there will be 23,880 new cancers of the brain and nervous system diagnosed in 2018.


About 17 percent of those cancers found in the brain will be glioblastoma, also known as, glioblastoma multiforme, or GBM, according to the American Association of Neurological Surgeons.

“Most brain tumors are not very aggressive, meaning there are lot of benign brain tumors, but this is an aggressive cancer of the brain,” Martinez said. “This is one of the more difficult cancers, of all the cancers, to treat.”

It most often affects older adults, in their 50s or 60s, Martinez said, but GBM can occur at any age.

“It is a tough diagnosis,” adds Dr. Geoffrey Lance Ray, radiation oncologist at the Sinai Department of Radiation Oncology. “It can infiltrate different parts of the brain and it is very resistant to treatment.”

There are also no regular screenings that can detect GBM in the way mammograms or colonoscopies can screen for breast cancer and colorectal cancer, according to Ray.

"Most of the times patients present with clinical symptoms. They may have headaches or seizures,” he said. “We typically do a CT scan and an MRI, and they see this mass on imaging and you have to get a diagnosis and so you get a biopsy.”

Treatment often starts with surgery, followed by chemotherapy and then radiation, and then more chemotherapy, according to Ray.

“We treat it pretty aggressively,” he said. “One of the scary things about it is it re-occurs usually in the area that you treat it. Even if you try the most aggressive radiation, the most aggressive surgery, you still have outcomes very similar to what they were maybe 10, 15 years ago.”


One reason for that may be that doctors and scientists don’t have the same basic understanding of the origins of GBM as they do other cancers, according to Martinez.

“It’s not really clear what the cause of this is. It’s not like there is an identified virus or chemical compound. Nicotine, for instance we know for lung and pancreatic cancer,” he said. “We are trying to figure out what can cause this.”

There is ongoing research, Martinez said, into the genetics of GBM, that has already distinguished certain mutations that make the tumors more or less resistant to chemotherapy.

“Hopefully this knew knowledge will translate into better treatments in the future,” he said. “Currently, the answer is, ‘Not yet.’ ”

But in the past couple of years, Ray said, a tool has shown up in the fight against GBM: tumor treating fields. This is a device that is worn on the patient’s shaved head that generates an electric field that interferes in the cell division of a tumor, he said.

“They have actually shown improvement in survival,” Ray said. “We actually have a new weapon with regards to treating glioblastoma.”


There are some drawbacks, however, according to Martinez.

“You have to shave your head, put some electrodes on the scalp and then those are attached to a battery pack in a bag the size of a woman’s handbag that you carry every day,” he said. “You have to use it 24 hours a day, which is obviously not convenient for everybody.”

And yet, Martinez said, one study found those who used tumor treating fields, or TTF, had a five-year survival rate three times higher than those who did not.

GBM is likely to remain a tough diagnosis for some time yet, Ray said, but one positive to the disease, he said, is that even aggressive treatment does not impact quality of life as much as treating some other cancers.

“It’s one of those we still haven’t been able to fight a good fight yet. You just have to think about the quality of life first, the type of life you want to live,” he said. “You don’t want to give up hope yet, but at the same time, you do have to get your life in order.”