Treatment for some aggressive brain cancer patients could be “revolutionised” after scientists found a new way to find out who might benefit from immunotherapy.

Some glioblastoma tumors may respond well to immunotherapy, but there is currently no way to assess this without an invasive brain biopsy – which carries the risk of infection and bleeding.

As a result, biopsies are rarely performed for glioblastomas before surgery to remove the tumor, meaning these patients do not benefit from improved treatments.

Now there is hope after researchers developed a new imaging technique that can help identify patients who will benefit from immunotherapy drugs without the need for a risky biopsy.

Experts hope the new imaging technique could soon guide personalized treatment for glioblastoma patients, and others called the discovery a “real step forward” for patients.

Glioblastomas are a fast-growing type of brain tumor.

Average survival after a diagnosis of glioblastoma is 12 to 18 months.

Only 25% of patients survive more than a year and only 5% of patients survive more than five years, according to figures from The Brain Tumor Charity.

The main treatments for glioblastomas are surgery, radiation therapy, and chemotherapy.

But now immunotherapy could be widely used thanks to the development of the new ‘immuno-PET imaging technique’ by scientists at the Institute of Cancer Research in London (ICR).

Higher levels of a protein called PD-L1 have been found in fast-growing glioblastoma tumors.

The ICR said this protein acts as the “brakes” on the body’s immune system, so blocking the function of this protein could “start” the immune system to fight cancer.

Until now, a biopsy was the only way to assess PD-L1 levels in the brain tumor.

Now scientists have developed a “radiotracer” that binds to PD-L1, allowing doctors to measure its levels in glioblastoma patients, the authors wrote in the journal Neuro-Oncology.

The tracer was tested on a small number of patients in Poland.

Eight patients with newly diagnosed glioblastoma received the tracer, followed by scans after 48 and 72 hours.

The scans showed that the tracer successfully binds to PD-L1 positive cells in the tumor and throughout the body.

Five of the patients also received pembrolizumab — a treatment that blocks PD-L1 function — before surgery.

The researchers found that these patients had lower levels of the tracer in their tumors – suggesting that the drug acts on the PD-L1 protein and removes the “brakes” on the immune system so it can fight the cancer.

Three of the five patients saw their cancer stabilize and not grow any further, the ICR said.

The ongoing clinical trial aims to recruit 36 ​​patients diagnosed with glioblastoma to see if pembrolizumab given before surgery is effective.

The researchers will also assess whether PET imaging with the radiotracer can be used to monitor progress and adjust treatment as needed.

“This study could revolutionize the treatment of glioblastoma, as we have shown that it is possible to image an immunotherapy target with our radiotracer,” said Dr. Gabriela Kramer-Marek, associate professor and group leader in preclinical molecular imaging at the ICR.

“Being able to scan the patient’s body and see the levels of this target means we can predict patients’ response, see the immune system responding to treatment and modify treatment where necessary – providing a personalized treatment plan based on characteristics unique characteristics of their tumor, all without the need for a preoperative biopsy.”

Professor Kristian Helin, Chief Executive of The ICR, added: “Glioblastoma is a devastating disease and treatments have not changed significantly for decades.

“Although immunotherapies appear to be effective, progress has been held back by the fact that they do not have a biomarker test to show who might benefit from them or a way to monitor each patient’s response to treatment.

“It’s fantastic to see the technological advances that mean innovative imaging techniques could soon guide personalized treatment.”

Dr Karen Noble, director of research, policy and innovation at Brain Tumor Research, said: “We are excited about the potential of this new imaging technique to transform the treatment landscape for patients with glioblastoma.

“The ability to identify those who would benefit from immunotherapy without the need for risky biopsies is a big step forward.

“Personalized treatment plans improve the chances that a treatment will be effective. We therefore welcome these promising results and look forward to seeing how this technique can improve the lives of patients with aggressive brain tumors.”

Dr Simon Newman, Scientific Director at the Brain Tumor Charity, said: “These tumors are notoriously difficult to treat and research into immunotherapy has had mixed results due to the tumor’s ability to hide from the immune system.

“However, we are encouraged by the findings of this study, as there is an urgent need for new approaches to monitor and treat this devastating disease.

“Immunotherapies have shown progress in other cancers, and we hope to see similar progress for brain tumors.

“We are excited to see progress in this area and look forward to following this work as it advances to larger clinical trials.”