Bevacizumab Versus Corticosteroids as First-line Treatment in Patients With Symptomatic Cerebral Radiation Necrosis After Radiation for High-grade Glioma or Brain Metastases

Cerebral radiation necrosis (CRN) is a severe complication of high-dose radiation for brain metastases (BM) or glioma, which can potentially cause significant neurologic symptoms leading to serious morbidity and impaired quality of life (QoL). The first-line therapy for symptomatic CRN (sCRN) is corticosteroids, primarily dexamethasone, which often leads to complications, refractory symptoms, and interference with anti-cancer treatment. Since 2017, bevacizumab, an antibody against Vascular Endothelial Growth Factor (VEGF), has been used in a second-line treatment setting for refractory sCRN. A small randomized clinical trial (RCT) has shown that bevacizumab significantly diminishes cerebral edema on MRI and decreases clinical symptoms of sCRN in irradiated glioma patients. Several non-randomized clinical studies demonstrated a beneficial radiological and clinical effect of bevacizumab in patients with sCRN after irradiation for BM. The optimal first-line treatment for sCRN is currently unknown. Effective and safe first-line treatment of sCRN will optimize the patient's well-being and health-related QoL. Furthermore, minimizing corticosteroid use will benefit the clinical treatment options and outcomes of concomitant or future anti-cancer treatment. This phase III multicenter, open-label, randomized clinical trial compares the clinical efficacy of first-line bevacizumab versus standard-of-care dexamethasone for sCRN in patients with high-grade glioma (HGG) or BM.

Inclusion Criteria: Inclusion all patients (both HGG and BM): 1. Age ≥ 18 years old 2. First episode of sCRN ≥ 3 months after completion of focal (re-)irradiation, as determined by the local Multidisciplinary Neuro-Oncology Board. A clear working diagnosis of CRN without evidence of a combination with tumour progression is required 3. KPS score ≤ 90 and either (a) a minimum loss of two points in at least one domain of the Neurologic Assessment in Neuro-Oncology (NANO) scale as compared to the maximum score of that domain due to sCRN, or (b) a headache attributable to sCRN with an average intensity ≥5/10 on the NRS, persisting for ≥10 consecutive days, with inadequate relief despite an adequate trial of paracetamol and/or an NSAID unless these medications are contra-indicated or not tolerated 4. Maximum daily dexamethasone use of 1 mg/day for the 8 weeks preceding randomization 1. Dexamethasone may have been prescribed for various indications, except for managing (ongoing) cerebral edema 2. Higher doses of dexamethasone are permitted 3 weeks immediately preceding randomization if used specifically for the treatment of sCRN 5. Able to understand the patient information, online tests and questionnaires 6. Written informed consent Inclusion BM: 1\. BM of solid tumour, including all primary tumour types Inclusion HGG: 1\. A confirmed histological diagnosis of high-grade diffuse glioma according to WHO 2021 criteria, including: astrocytoma, IDH-mutant, grade 3-4; astrocytoma, IDH-wildtype (sybtype molecular glioblastoma); oligodendroglioma, 1p/19q codeleted, grade 3; diffuse glioma, NEC, grade 3-4; or glioblastoma, IDH-wildtype, grade 4 Exclusion Criteria: A potential subject who meets any of the following criteria will be excluded from participation in this study, both for the BM and HGG group: 1. Prior treatment with bevacizumab \