As brain tumors grow, they must do one of two things: push against the brain or use finger-like extensions to invade and destroy surrounding tissue.

Previous research found tumors that push — or put mechanical force on the brain — cause more neurological dysfunction than tumors that destroy tissue. But what else can these different tactics of tumor growth tell us?

Now, the same team of researchers from the University of Notre Dame, Harvard Medical School/Massachusetts General Hospital, and Boston University has developed a technique for measuring a brain tumor’s mechanical force and a new model to estimate how much brain tissue a patient has lost. Published in Clinical Cancer Research, the study^[1] explains how these measurements may help inform patient care and be adopted into surgeons’ daily workflow.

“By adding a two-minute step to a surgeon’s procedure, we were able to distinguish between a glioblastoma tumor versus a metastatic tumor based on mechanical force alone,” said Meenal Datta, assistant professor of aerospace and mechanical engineering at Notre Dame and co-lead author of the study.

Datta and collaborators collected data from 30 patients’ preoperative MRIs and their craniotomies, which include exposing the brain and using Brainlab neuronavigation technology. This technology provides surgeons with real-time, 3D visualization during brain surgeries and is considered commonly available for neurological procedures. Neurosurgeons can use this technique to measure the bulge caused by brain swelling from the tumor’s mechanical forces before the tumor is resected.

Then this patient data was used to determine whether brain tissue was displaced by a tumor’s mechanical force or replaced by a tumor. The researchers found that when there is more mechanical force on the brain (displacement), the swelling will be more substantial. But when a tumor invades and destroys surrounding tissue (replacement), the swelling will be less significant.

The researchers created computational models based on a point system of measurements and biomechanical modeling that can be employed by doctors to measure a patient’s brain bulge, to determine the mechanical force that was being exerted by the tumor, and to determine the amount of brain tissue lost in each patient.

Funded by the National Institutes of Health, National Science Foundation and various cancer research foundations, this study is among the first to show how mechanics can distinguish between tumor types.

Datta recently showed that even affordable and widely used blood pressure medications can counter these effects. “We’re hoping this measurement becomes even more relevant and that it can help predict outcomes of chemotherapy and immunotherapy.”

To get a better idea of what else mechanical force could indicate, the research team used animal modeling of three different brain tumors: breast cancer metastasis to the brain, glioblastoma and childhood ependymoma.

In the breast cancer metastasis tumor, researchers used a form of chemotherapy that is known to work in reducing metastasis brain tumor size. While waiting for the tumor to respond to the chemotherapy, the team found that a reduction in mechanical force changed before the tumor size was shown to change in imaging.

Datta hopes that doctors employ the patient models from the study to continue to grow the field’s understanding of how mechanical force can improve patient care management.

Reference:

1. https://doi.org/10.1158/1078-0432.CCR-24-4159

(Newswise/SS)