HGG-58. SIOPE HGG Working Group approach to obtain consensus on management of paediatric high grade glioma across Europe

BACKGROUND: There is currently no European standard clinical practice on the management of paediatric HGG (pHGG). AIMS: To develop approved clinical recommendations for the management of pHGG reflecting current best practice, with the ultimate aim of improved outcomes. METHODS: An open questions survey was performed to establish the status quo regarding standards of care in pHGG across Europe. National coordinators from 33 countries were invited to participate in the process. RESULTS: 32 out of 33 countries completed the survey. Substantial areas of agreement were reached. All 32 countries agreed that hemispheric pHGG should be treated with radiotherapy and adjuvant chemotherapy after surgical resection. 30/32 (94%) countries proposed initial radiotherapy with concomitant temozolomide where 23/32 (72%) countries recommended a complementary adjuvant chemotherapy (Lomustine, Valproic acid, or Nivolumab). 32 countries agreed H3K27M diffuse midline glioma DMG, including DMG of the pons (DIPG), should be treated with radiotherapy. 10/32 (31%) countries proposed radiotherapy alone at diagnosis. There was no consensus on the role of adjuvant chemotherapy; temozolomide was recommended in 9/32 (28%), while mTOR inhibitor in 7/32 (22%) countries. A biopsy of DIPG was routinely offered in 18/32 (56%) countries, while in 4 countries was considered on an individual basis. Six countries never performed a biopsy. Re-irradiation at the relapse was consensual in 26/32 (81%) countries. Certain areas of divergence were identified. A Delphi method is being employed to reach a general consensus on those areas. CONCLUSION: This two-step approach will help us to set up the European guidelines on the management of pHGG based on the current best standard of care. This approach will also identify areas, which should be the focus of future collaborative studies. Such efforts will ultimately translate into improved patient outcomes.