By Dr. Maria Simbra

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PITTSBURGH (KDKA) — It was once one of the most feared viruses in the world, but now researchers say they are using it to treat one of the most common and aggressive types of brain cancer.

An unexpected ally has been discovered in the fight against brain cancer — the polio virus, which is usually known for causing paralysis and death.

Researchers have genetically changed the infectious agent so that it instead targets specific proteins on the cancer cells and kills a malignancy called gliobastoma multiforme, an aggressive cancer that comes from the brain tissue itself.

(Photo Credit: CBS)

It is usually treated with surgery, chemotherapy and radiation, but it can come back.

“The tumor cells are thought to be located in other parts of the brain in which MRI cannot pick up,” explains Allegheny General Hospital neurosurgeon Dr. Alexander Yu.

And it has a grim prognosis.

“Twelve to 18 months is typically what most patients go through,” Dr. Yu says.

During surgery, the tumor is removed, and the virus is placed in the cavity that remains.

“It does rev up the immune system, to allow the immune system to attack those tumor cells also,” he adds.

The study from Duke University, published in the New England Journal of Medicine, involved 61 patients. One group got the virus, and one group did not for comparison. At three years, 21 percent of the virus treated group survived, compared to four percent of the comparison group.

What’s more, three patients have survived more than five years.

This approach does have risks, brain swelling and seizures, for instance. And in one case, a life-threatening blood clot had to be surgically removed.

If studies continue to go well, this doctor envisions the therapy adding options, but not becoming a substitute treatment.

“This type of therapy will be one part of the big picture,” says Dr. Yu.

Dr. Maria Simbra