A prospective study of late cognitive effects and imaging changes after proton radiotherapy

Children who survive brain tumours often struggle with learning and memory years after proton radiotherapy, and this study will track exactly which tiny brain regions are most vulnerable to radiation damage. The problem is that proton therapy spares healthy tissue better than standard X-ray radiotherapy, but it still causes cognitive decline in many children. Doctors cannot currently predict which patients will be affected, nor do they know precisely which brain structures are most sensitive. This study addresses that gap by combining three approaches: detailed radiotherapy dose maps, advanced MRI scans, and blood tests for biomarkers of radiation injury. If successful, the research could change how proton therapy is delivered. Clinicians might adjust treatment plans to avoid the most sensitive brain regions, reducing long-term cognitive harm. The blood test could also flag children at risk early, allowing for timely educational support or cognitive rehabilitation. Because the study runs alongside parallel protocols in the Netherlands and the United States, the findings will be internationally applicable. This is applied clinical research with a clear practical goal: improving quality of life for young brain tumour survivors.