A common medical test may help predict how long patients with cancer that has spread to the brain might survive and whether they are likely to respond to immunotherapy.

Researchers from the University of Liverpool and the Walton Centre in Liverpool utilized a novel MRI technique called Diffusion Tensor Imaging (DTI), which has the potential to remove the need for patients to undergo costly and dangerous biopsies.

Cancer is often treated with chemotherapy or with targeted therapies including immunotherapy, which works by stimulating the body’s immune system to fight cancer and does not come with as many of the debilitating side effects as chemotherapy.

However, it does not work for everyone or for every type of cancer and there is no simple test to determine who is likely to benefit.

“There is huge excitement about immune therapy in brain tumors but without the time and risk of a neurosurgical operation it is impossible to know which patients should have treatment,” Walton Centre Research Fellow Dr. Rasheed Zakaria, said in a statement. “Since most patients with a brain tumor undergo MRI scanning we asked the simple question, are there any changes on the MRI scans that correlate with the brain's immunological reaction to the cancer?”

The researchers used DTI to analyze brain tumors from appropriate patients. They then sampled the same areas for comparative biochemical tests.

This revealed that the higher the level of immune reactive cells around the tumors, the longer a patient survives, irrespective of the cancer type of other biological parameters. That level matched what was derived from the DTI technique.

“The result suggests that the immune system is holding in check some metastatic cancers and that monitoring just one metastasis in the brain is a reflection of the body's overall control of the disease,” Philip Rudland, Ph.D., a professor at the University of Liverpool, said in a statement.

The researchers now plan on repeating the study with a larger group of patients with brain metastasis to validate the findings. They will then trial the approach in selecting patients for immunotherapy.

The study was published in Cancer Research.