Observational Study for Assessing Treatment and Outcome of Patients With Primary Brain Tumours Diagnosed According to cIMPACT-NOW Recommendations and the 2021 WHO Classification.

The goal is to determine whether the new 2021 WHO classification, based on cIMPACT-NOW recommendations, results in more homogeneous patient groups than the old 2016 classification. Furthermore, it will help derive provisional guidelines on how patients with these newly defined tumour entities are best treated. These recommendations will be based on the experience of EORTC investigators with chosen treatments and their experience as reported in this data collection report.