Bevacizumab For The Treatment Of Brain Radionecrosis In Cancer Patients.

e19352 Background: Brain radionecrosis (BRN) occurs as a result of radiation therapy for brain tumors or metastatic brain lesions. BRN is characterized by an increase in permeability and disruption of the blood-brain barrier (BBB). There are currently no standard treatment options for BRN. While the mechanism of BRN is unknown, it is hypothesized that there is an inflammatory reaction of the local tissue to radiation which results in a continuous process involving endothelial cell dysfunction. This leads to tissue hypoxia and increased vascular endothelial growth factor (VEGF) which in turn causes capillary leakage, progressive BBB dysfunction, and cerebral edema. Bevacizumab (BEV), a humanized monoclonal antibody with action against VEGF, has recently been used in some studies for the treatment BRN. BEV essentially blocks VEGF from reaching its targets on the endothelium, thus making it an ideal treatment modality for BRN. Methods: The primary purpose of this study is to assess the effectiveness and safety of BEV for the treatment of BRN. Fifteen patients (pts), 14 diagnosed with lung cancer and one with breast cancer, that had BRN and treated with BEV between January 2014 and November 2019 were identified from Memorial Cancer Institute's database. A retrospective chart review analyzing pts's age, sex, BEV dose, dosing frequency, number of treatments received, medication-related adverse effects, and clinical benefit was conducted. Brain imaging pre-treatment and after four cycles of therapy were compared to assess the efficacy of BEV. Pts who exhibited clinical benefit (complete response (CR), partial response (PR), or stable disease (SD)) received an additional four cycles of treatment. Results: The median age was 65 years (y) (49-78y) and 10/15 (67%) of pts were female. Clinical benefit was achieved in 13/15 (87%) of pts. The most frequent dosing regimen administered was 10 mg/kg every two weeks and the median number of cycles given was eight cycles (1-12). Treatment with BEV was well tolerated with eight pts (53%) experiencing BEV-related Grade 2 or less adverse effects (AE), including hypertension (27%), proteinuria (13%), thrombocytopenia (7%), and mild nose bleeds (7%). There were no Grades 3-5 AE. Conclusions: This study demonstrates that there is a clinical benefit when administering BEV for the treatment of BRN. BEV was well tolerated and has an acceptable safety profile.