University of Minnesota targets brain cancer with new form of radiation therapy

Cancer specialists at the University of Minnesota are the first to try a new form of brachytherapy — radiation-releasing implants — to target hard-to-kill brain tumors and prevent them from returning.

One patient at the U has already received GammaTile Therapy, which was federally approved last year and marketed as a more focused form of radiation that could reduce damage to healthy tissue and resulting side effects.

"It's about how to give better radiation therapy, and how to give radiation more safely," said Dr. Clark Chen, head of the U's neurosurgery department.

Radiation therapy has been a particular need for brain tumors because cancer-killing chemotherapy drugs have been unable to pass through the brain's protective blood barrier to reach tumor sites.

Researchers have sought for decades to increase the precision of radiation therapy, which traditionally has been provided through external beams aimed at tumors. One solution has been using multiple, pencil-sized beams to direct radiation in shapes that more closely resemble patients' tumors.

Brachytherapy is exciting because it can provide localized treatment and avoid the wounds that can occur when radiation penetrates the skin, Chen said, but it presents complications as well. And doctors have had to perform follow-up procedures to remove the implants that had been emitting radiation.

Chen said the GammaTile is an upgrade because it implants the radiation source in packs that are commonly left inside surgery patients to prevent bleeding and dissolve on their own. And they can be implanted during tumor-removal surgeries, whereas external radiation is provided over multiple follow-up visits.

The Food and Drug Administration approved GammaTile for patients whose tumors are recurrent, which means they regrow after surgical attempts to remove them. While the implants cost thousands of dollars, depending on their radiation dosages, some health care economists believe they could reduce costs if they prevent the need for multiple radiation beam appointments.

Radiation is released in a small, controlled area by GammaTile, which means it can emit higher dosages that have better chances at killing tumors and preventing them from re-forming, Chen said. But that short range also means it won't work for patients with larger or sporadic tumors, who would be more appropriate candidates for beam radiation.

"The range is both a blessing and a curse," said Chen, who added that he has no financial ties to the manufacturer.

The first patient is doing well, he said. The woman suffered from glioblastoma, one of the most aggressive forms of brain cancers. She embraced being the first recipient, because she wanted the best chance at surviving and seeing her teenage son graduate from high school.