A new study offers fresh hope for people diagnosed with glioblastoma, one of the most aggressive and deadly brain cancers.
Researchers at Keck Medicine of USC have found that using an electric field therapy device on the scalp, combined with chemotherapy and immunotherapy, could help patients live significantly longer—especially those with large tumors that cannot be removed by surgery.
Glioblastoma is a fast-growing cancer with very few treatment options. The average survival time after diagnosis is only about eight months.
Standard treatments like chemotherapy and immunotherapy often don’t work well because the brain’s natural defense system, called the blood-brain barrier, blocks helpful immune cells and medicine from reaching the tumor.
In this study, researchers tested a device called Tumor Treating Fields (TTFields), which delivers low-intensity, alternating electric fields directly into the brain tumor.
These fields disturb the inner structure of cancer cells, stopping them from multiplying.
But even more importantly, the electric fields appear to alert the body’s immune system, drawing in T cells—special white blood cells that attack cancer.
The researchers discovered that once these T cells were inside the tumor, giving the patient immunotherapy helped those cells stay active and even led to more powerful cancer-fighting cells appearing. In this way, TTFields “wakes up” the immune system, making immunotherapy finally effective against glioblastoma.
Patients in the study wore the device for about 18 hours a day while also receiving chemotherapy (temozolomide) and immunotherapy (pembrolizumab).
Among 26 patients who completed this treatment, survival improved by about 10 months compared to patients who only used the electric field device and chemotherapy in earlier studies.
For patients with large, inoperable tumors—who usually have the worst outcomes—survival increased by an average of 13 months. These patients also showed stronger immune responses, possibly because bigger tumors give the immune system more targets to attack.
Dr. David Tran, chief of neuro-oncology at Keck Medicine and lead author of the study, said the key to this success may be starting the immune response directly inside the tumor using electric fields.
This “in situ immunization” helps the body recognize and attack the cancer, something that’s been very hard to do with glioblastoma in the past.
The study was based on data from a Phase 2 clinical trial with 31 newly diagnosed patients. Now, a much larger Phase 3 trial is underway across the U.S., Europe, and Israel to confirm the results. Over 740 patients will be enrolled by 2029, including those who had surgery and those who didn’t, to better understand how removing part of the tumor affects the immune response.
For now, the combination of electric fields, immunotherapy, and chemotherapy may bring a powerful new strategy to fight one of the most difficult cancers. It’s especially encouraging news for patients with few options left.
