High-grade astrocytoma: combining two treatments opens a new therapeutic avenue

Participants were assigned to two approaches: either laser interstitial thermal therapy (LITT) or surgery with biopsy, followed in both cases by pembrolizumab treatment.  

For LITT, neurosurgeons used MRI to precisely locate the tumor, guide the laser probe, and deliver heat in a targeted manner. The hyperthermia destroys tumor tissue while preserving surrounding healthy structures and, crucially, disrupts the blood–brain barrier for several weeks.  

According to the team’s previous work, this time window may allow T cells activated by pembrolizumab to enter the brain and exert cytotoxic activity.  

The reported data are striking. Nearly half of the patients treated with LITT followed by pembrolizumab were still alive 18 months after treatment. By contrast, none of the patients who received the conventional treatment (surgery followed by pembrolizumab) were alive at 18 months.  

More than one third of patients in the LITT–immunotherapy group survived beyond three years, far exceeding the expected four to five months of survival for recurrent high-grade astrocytoma.  

Disruption of the blood–brain barrier appears to play a central role. “This alerts T cells to the presence of the tumor and facilitates their migration to the tumor to locate and attack it,” explained Professor David Tran, MD, PhD, head of neuro-oncology at Keck Medicine, co-director of the USC Brain Tumor Center, and senior author of the study, in a press release.  





Lifting the brain’s immune lock




He emphasized the potential clinical significance of these findings. “They suggest that LITT can enhance the effectiveness of the immune checkpoint inhibitor pembrolizumab against high-grade astrocytoma. Patients with this type of advanced cancer have few therapeutic options and a poor prognosis. This approach could significantly extend their life expectancy and offer new hope to patients and their loved ones.”  

As the U.S. Food and Drug Administration has since authorized LITT for certain brain tumors, and pembrolizumab is already approved in multiple oncology indications, these results pave the way for larger-scale trials. They also encourage exploration of other combinations aimed at modulating the blood–brain barrier to optimize intracranial immunotherapy.  





About the Author – Elodie Vaz
Health journalist, CFPJ graduate (2023).
Élodie explores the marks diseases leave on bodies and, more broadly, on human life. A registered nurse since 2010, she spent twelve years at patients’ bedsides before exchanging her stethoscope for a notebook. She now investigates the links between environment and health, convinced that the vitality of life cannot be reduced to that of humans alone.