Researchers at Keck Medicine of USC may have found a way to help patients fighting one of the most aggressive forms of brain cancer. High-grade astrocytoma, which includes glioblastoma, is notorious for growing fast and returning even after a tumor is removed. Usually, patients facing a recurrence only survive for about four to five months.

The problem is a matter of access. The body has a “blood-brain barrier” that acts like a security fence, protecting the brain from the bloodstream. While this keeps us healthy, it also blocks life-saving immune cells and drugs from reaching a tumor.

Laser Heat

In a recent clinical trial, doctors tested a combination of a laser procedure and an immune-boosting drug called pembrolizumab. The procedure, known as laser interstitial thermal therapy (LITT), uses an MRI-guided probe to heat and destroy tumor tissue.

The heat thins out that protective blood-brain barrier for a few weeks. This window allows the drug to do its job, letting the body’s T-cells “see” the cancer and rush in to attack it.

“These results suggest that LITT can help the immune checkpoint inhibitor pembrolizumab work more effectively against high-grade astrocytoma,” said David Tran, MD, PhD, the lead author of the study. “Patients with this type of advanced cancer have few remaining options and poor outcomes, and this approach could meaningfully extend their survival time and provide new hope for patients and their loved ones.”

Striking Cancer Survival Rates

The numbers from the study, published in Nature Communications, tell a compelling story. Nearly half of the patients who received the laser treatment followed by the drug were still alive at 18 months. For comparison, every single patient in the study who received traditional surgery and the drug passed away before the 18-month mark.

According to the long-term data, over one-third of the laser-treated patients lived longer than three years.

“This alerts T-cells to the presence of the tumor and provides easy passage of these T-cells to rush in, find and attack the tumor,” Tran explained. For a group of patients who were already on their second or third bout with cancer, these extra years represent a significant step forward in brain cancer treatment.