MADISON, Wis. – UW Health recently became one of the first health systems in Wisconsin to offer a new way to deliver targeted radiation therapy directly to the site of certain brain tumors during surgery.
GammaTile, developed by Tempe, Arizona-based GT Medical Technologies, consists of small, absorbable collagen tiles, each containing four radioactive cesium-131 seeds. After a brain tumor is surgically removed, the tiles are placed along the surgical cavity to treat microscopic tumor cells that may remain.
Radiation treatment begins immediately, with approximately 90% of the dose delivered over the next month or so. GammaTile is cleared by the U.S. Food and Drug Administration for patients with newly diagnosed malignant brain tumors and patients with operable recurrent brain tumors, including certain brain metastases, glioblastomas and meningiomas.
At UW Health, GammaTile treatment is planned and delivered by a multidisciplinary team of neurosurgeons, radiation oncologists and medical physicists as part of the Departments of Neurosurgery and Radiation Medicine’s joint intracranial brachytherapy program.
The approach, which UW Health began offering in October, has several potential advantages, according to Dr. Brett Morris, radiation oncologist, UW Health | Carbone Cancer Center, and assistant professor of radiation medicine, University of Wisconsin School of Medicine and Public Health.
Traditional external-beam radiation therapy directs radiation toward the tumor site from outside the body. Modern techniques can precisely shape the radiation dose, but some surrounding healthy brain tissue may still receive radiation. GammaTile instead delivers radiation directly to the surgical cavity, concentrating the dose near the area at greatest risk for tumor recurrence, Morris said.
“Our goal is to treat microscopic tumor cells that might remain after surgery while limiting radiation exposure to healthy brain tissue,” he said. “That precision is especially important in the brain, where we want to preserve neurologic function and quality of life.”
Another potential advantage is that radiation treatment begins at the time of surgery, rather than after the several-week surgical recovery period typically needed before external-beam radiation can start, according to Dr. Azam Ahmed, neurosurgeon, UW Health, and associate professor of neurosurgery, radiology and otolaryngology, UW School of Medicine and Public Health.
“Treatment starts as soon as we remove the tumor and place the tiles in the surgical cavity,” he said. “We remove as much of the tumor as we safely can, and the tiles immediately begin treating any microscopic tumor cells left behind. For many patients, that also means no separate course of radiation appointments after surgery.”
GammaTile may also provide a treatment option for select patients with recurrent tumors, including some who have previously received external-beam radiation, according to Morris.
“When a brain tumor returns after radiation therapy, our treatment options can be limited,” he said. “For carefully selected patients who need another surgery, GammaTile may allow us to deliver an additional, highly localized course of radiation while accounting for the radiation they have already received.”
GammaTile is not appropriate for every patient or tumor type, and patients should discuss the option with their multidisciplinary care team. In some situations, GammaTile can be combined with external-beam radiation therapy.
Morris and his colleagues hope to participate in clinical trials evaluating how GammaTile may improve outcomes when used alongside other standard treatments. GammaTile has been studied in both newly diagnosed and recurrent brain tumors, including brain metastases and glioblastoma. For example, results from the Phase 3 randomized ROADS clinical trial, published in the Journal of Clinical Oncology in September, found that the 12-month rate of tumor recurrence at the surgical site was 1.3% for patients with newly diagnosed brain metastases treated with GammaTile during surgery, compared with 15.4% for those treated with stereotactic radiation after surgery. And, an ongoing Phase 3 trial, the BRIDGES trial, is now testing whether GammaTile can improve outcomes for patients with newly diagnosed glioblastoma, an aggressive brain cancer for which the therapy is already FDA-cleared.
“The ROADS trial provides evidence that GammaTile can improve tumor control for patients undergoing surgery for newly diagnosed brain metastases,” Morris said. “We hope to help expand this research and determine how GammaTile can contribute to better outcomes for patients with other brain tumors, including glioblastoma.”
