Simple SummaryFocal radiation necrosis of the brain (fRNB) is a late side effect that can occur after treatment of brain lesions with focal radiation therapy (stereotactic radiosurgery [SRS] or stereotactic radiation therapy [SRT]). This is becoming more common as more cancer patients are receiving effective systemic therapy for brain metastases, extending survival, and putting them at risk for fRNB. Currently, treatment options are limited to long-term corticosteroid therapy, which has significant side effects, or surgery with its inherent risks. Bevacizumab, a monoclonal antibody that targets the vascular endothelial growth (VEGF), is effective in treating fRNB but its use has remained limited due to its cost. In this single-center case series, a fixed low dose of bevacizumab (400 mg loading dose followed by 100 mg every 4 weeks) was shown to be a safe and cost-effective alternative treatment option for fRNB.AbstractFocal radiation necrosis of the brain (fRNB) is a late adverse event that can occur following the treatment of benign or malignant brain lesions with stereotactic radiation therapy (SRT) or stereotactic radiosurgery (SRS). Recent studies have shown that the incidence of fRNB is higher in cancer patients who received immune checkpoint inhibitors. The use of bevacizumab (BEV), a monoclonal antibody that targets the vascular endothelial growth factor (VEGF), is an effective treatment for fRNB when given at a dose of 5–7.5 mg/kg every two weeks. In this single-center retrospective case series, we investigated the effectiveness of a low-dose regimen of BEV (400 mg loading dose followed by 100 mg every 4 weeks) in patients diagnosed with fRNB. A total of 13 patients were included in the study; twelve of them experienced improvement in their existing clinical symptoms, and all patients had a decrease in the volume of edema on MRI scans. No clinically significant treatment-related adverse effects were observed. Our preliminary findings suggest that this fixed low-dose regimen of BEV can be a well-tolerated and cost-effective alternative treatment option for patients diagnosed with fRNB, and it is deserving of further investigation.