This working group includes over 10 members, comprising neuro-oncologists, pathologists, radiologists, and biologists from across Europe, united by the goal of developing better treatment options for children and adolescents diagnosed with these highly aggressive central nervous system tumours. The field of paediatric HGG has evolved significantly in recent years, reflecting the growing understanding of the complex biology of these tumours: new tumour entities have been introduced, while others have been revisited or even removed from the WHO classification of CNS tumours.
A significant achievement of the group has been the establishment and continued growth of the SIOPE DIPG/DMG Registry. This pan-European initiative was created to collect clinical, radiological, and, when available, molecular data from patients with diffuse intrinsic pontine glioma (DIPG) or diffuse midline gliomas (DMG). The registry enables comprehensive epidemiological studies and accelerates research into prognostic and predictive biomarkers. Additionally, it serves as a vital infrastructure for promoting international collaboration, data sharing, and quality-controlled imaging reviews—elements that are essential for advancing research in these rare pediatric cancers.
Another important contribution of the working group has been shaping the ERN PaedCan Clinical Practice Guidelines for Paediatric High-Grade Gliomas and Diffuse Midline Gliomas. Input from the key members of the working group helped define recommendations on imaging, biopsy, pathology, molecular testing, treatment options and palliative care. The guidelines reflect the most recent scientific evidence, incorporate molecularly driven classification principles, and highlight current standards of care from diagnosis through follow-up, but also identify areas where further research and collaboration are needed. The aim is to reduce disparities in care and ensure that children across Europe benefit from consistent, high-quality clinical management.
A commitment of the past years has been the preparation of the first SIOPE-BTG-HGG clinical trial that will be a cooperative randomised trial for the treatment of newly diagnosed and recurrent HGG, including DIPG and DMG in children, adolescents, and young adults. The trial, which is expected to run by the end of 2026-beginning of 2027 in six European countries, focuses on combination therapies that include chemo/radiotherapy and agents targeting the tumour microenvironment. These agents comprise drugs that influence glioma-neuronal interactions, promote autophagy, target tumour cell metabolism, or act as targeted therapies.
The HGG WG is also a group in which single-centre, collaborative, and international studies on HGG are shared and discussed among the members, to enable colleagues from different countries to participate whenever feasible or to refer patients if needed, to offer various treatment options.
Members of the WG have been involved in the pilot phase of the ERN PaedCan CNS tumour board (2022-2023), the EU-funded virtual multidisciplinary tumour board for children with CNS tumours conducted within ERN PaedCan. This tumour board has been resumed in 2025.
The pHGG/DMG working group meets twice a year, preferably in person, although online meetings are also held. During these meetings, members discuss updates on ongoing projects, present and receive feedback on special or challenging cases, and report on new projects or collaborative ideas.