Researchers have found that the risk of a brain tumour coming back can be better predicted by counting the number of immune cells in the tumour under a microscope. This result comes from research by the Leiden University Medical Center (LUMC), Erasmus MC and Heidelberg University
A meningioma is the most common type of brain tumour. It doesn’t grow inside the brain itself, but on the inner side of the membranes around the brain. Most meningiomas are benign, meaning not cancerous, but they can still cause serious symptoms like headaches or loss of bodily functions because they press on the brain.
Treatment usually involves surgery, radiotherapy, or both. Radiation can also cause side effects that significantly affect daily life, such as problems with concentration, memory loss, and fatigue where some meningiomas can return over time. This uncertainty about whether a tumour will recur is distressing for many patients.
Why prediction is difficult
Doctors typically place tumours into risk groups to estimate how likely they are to come back. For many cancers this works well: a low-risk tumour usually stays low-risk, but with meningiomas, even tumours classified as low-risk can still reoccur.
Until now, predicting risk has often involved analysing the tumour’s DNA profile which is a process requiring advanced and expensive technology. The researchers wanted to find a method that was both more accurate and cheaper so that it could be used globally, including in countries without access to high-tech tools.
Large international dataset and new insight
Thanks to collaboration with Professor Felix Sahm at Heidelberg University, the team analysed the DNA profiles of tumours from some 4,500 patients one of the largest collections of meningioma genetic data in the world.
They found that risk groups based on DNA don’t form clear, separate categories but rather overlap on a continuous scale. A tumour sample can even have both high and low-risk features in different parts of the same tumour.
What makes the new method simple
When the researchers looked at the tumour tissue under a microscope, they noticed something important: it’s not just the tumour cells that matter the immune cells within the tumour are key. Tumours with lots of immune cells tended to be lower risk, while those with fewer immune cells tended to be higher risk.
Because counting immune cells under the microscope is a standard, inexpensive practice in pathology labs, this approach could improve risk prediction without requiring costly DNA analysis.
It’s not yet certain whether this method will replace DNA testing in places like the Netherlands, but the researchers plan to compare how accurate the new approach is and work on it further in the coming years.
