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NEW YORK (Reuters) - There is at least one approved device and scores of experimental treatments being tested that could improve the odds of longer-term survival for patients with the type of extremely aggressive brain cancer afflicting U.S. Senator John McCain.
While the 80-year-old Arizona Republican, who was re-elected to a sixth Senate term in November, recovers from surgery to remove a blood clot found to be associated with the cancer, he and his medical team will explore treatment options.
"That (recovery) usually takes about 10 to 14 days before starting therapy," said Dr. Maciej Lesniak, chair of neurological surgery at Northwestern Memorial Hospital in Chicago.
McCain was diagnosed with glioblastoma, a brain cancer with very poor prognosis that took the life of former U.S. Senator Edward Kennedy in 2009. Surgery is performed to remove as much of the tumour as possible, but cancer cells are left behind that infiltrate the brain and quickly grow.
The survival rate with standard treatment is generally about 15 months, with only about 25 percent of patients alive after two years.
Standard treatment is a combination of 30 doses of radiation administered over six weeks along with the oral chemotherapy Temodar (temozolomide) sold by Merck & Co. After a three-to-four week break, additional four-week cycles of Temodar are given.
McCain has vowed to return to his Senate duties soon.
Experts said he may well be able to do so.
The treatment is usually very well tolerated, Lesniak said. "Generally, people can maintain normal quality of life during therapy including their work in the majority of cases."
Doctors interviewed who are not involved in McCain's care said further combination therapies were likely needed to sharply improve patient outcomes. Debates over when to begin such therapies are ongoing.
"Many people feel we need to push the envelope and look at combination therapy as early as possible in addition to the standard of care," Lesniak said.
There are about 150 clinical trials for glioblastoma under way, most at very early stages, and the majority for patients for whom initial therapy has stopped working.
McCain could be a candidate for a trial in newly diagnosed patients.
Current immunotherapies that have shown great promise against melanoma, lung cancer and other cancers are unlikely by themselves to work in glioblastoma because the tumours tend not to present the proper target for those drugs.
"Glioblastoma tumour cells are incredibly heterogeneous. No two tumour cells are alike," said Dr. John de Groot, professor of neuro-oncology at the University of Texas MD Anderson Cancer Center, adding that a multi-pronged approach was likely needed.
One promising approach being tested in early stage clinical trials by various institutions and companies involve injecting viruses into the tumour to destroy cancer cells and spur an immune system attack.
Duke University generated publicity last year with reports of early success using the polio virus against brain cancer.
MD Anderson developed a viral therapy that it outlicensed to a company called DNAtrix for further development, de Groot said.
A trial at Northwestern is using neural stem cells to help improve the performance of a cancer-fighting virus.
"Stem cells when loaded with the virus can travel to areas we can't resect to deliver the virus throughout the tumour mass in a more uniform fashion," Lesniak said.
In a study published in May in the journal Nature, Duke researchers reported early success with a vaccine that delivers high doses of Temodar to the tumour.
Among 11 patients in that study, the median survival was 41.1 months, versus 14.6 months for the standard treatment.
Dr. Roger Stupp, co-director of the Northwestern Brain Tumor Institute, who is credited with pioneering the radiation/Temodar combination therapy for glioblastoma, said patients like McCain might be helped by a now-approved device shown to extend survival.
Called Optune and sold by Novocure Ltd, it delivers an electromagnetic field that interferes with cancer cells' ability to divide and survive, said Stupp, who led trials of the device.
It involves electrodes placed on the scalp operated by a small battery pack. With Optune worn nearly 24 hours a day, the two-year survival rate in the trial that led to its approval jumped to 43 percent, with some patients living four years or more.
"My recommendation is to use it early in the disease course," Stupp said.
Reporting by Bill Berkrot; Editing by Peter Cooney