RADT-04. Bevacizumab for the management of pediatric radiation necrosis in CNS malignancies

Abstract Central nervous system (CNS) tumors represent the second most common cause of pediatric cancer. Standard treatment includes tumor resection, chemotherapy, and radiation therapy (RT). While RT can effectively delay tumor progression, the risk of radiation necrosis (RN) remains a significant concern. Bevacizumab, a VEGF inhibitor, is well-established for treating RN in adults due to its ability to reduce brain edema; however, high-quality prospective data on its use for pediatric radiation necrosis (PRN) in patients with CNS malignancies are limited. A systematic review was conducted using PubMed and Google Scholar to identify studies published from 1990 to 2024 reporting outcomes of pediatric patients (22 years old) with CNS malignancies treated with bevacizumab for PRN. Thirteen studies met inclusion criteria. Key variables, including tumor location, RT modality and dose, bevacizumab dose, adverse effects, time from RT to PRN, and clinical and radiographic response rates, were summarized. A total of 169 patients were examined overall with 57 of them developing radiation necrosis, and 39 of these 57 patients (59.6%) demonstrated clinical improvement following bevacizumab treatment. Regarding RT modalities, 59.6% received external beam RT (EBRT), 8.8% proton beam RT (PBRT), 5.3% stereotactic radiosurgery (SRS), and 3.5% fractionated stereotactic RT (FSRT), with a mean RT total dose (range) of 18.5-59.4 Gy. These findings suggest a growing body of evidence supporting the use of bevacizumab in managing PRN, both therapeutically and prophylactically, in pediatric patients with CNS tumors. Additionally, bevacizumab’s potential antitumor effects via edema reduction complicate distinguishing treatment response between RN resolution and tumor regression, warranting further investigation.