RADT-33. RADIOSURGERY VERSUS COMBINATION RADIOSURGERY-BEVACIZUMAB FOR THE TREATMENT OF RECURRENT HIGH-GRADE GLIOMA: A SYSTEMATIC REVIEW

Abstract BACKGROUND High-grade gliomas (HGG) comprise the most common primary adult brain cancers and universally recur. Combination re-radiation therapy (reRT) and bevacizumab (BVZ) therapy for recurrent HGG is common, but its reported efficacy is mixed. OBJECTIVE To assess clinical outcomes after reRT±BVZ in recurrent HGG patients receiving stereotactic radiosurgery (SRS), hypo-fractionated (HFSRT), or fully fractionated RT (FSRT). METHODS We performed a systematic review of PubMed, Web of Science, Scopus, Embase, and Cochrane databases, following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. We identified studies reporting outcomes for patients with recurrent HGG treated via reRT±BVZ. Cohorts were stratified by BVZ treatment status and reRT modality (SRS, HFSRT, and FSRT). Outcome variables were overall survival (OS), and progression-free survival (PFS). RESULTS 34 of 1,742 identified articles survived inclusion criteria (2%) and reported data on 954 patients receiving reRT alone and 445 patients receiving reRT+BVZ. All patients initially underwent standard-of-care therapy for their primary HGG. In a multivariate analysis that adjusted for median patient age, WHO Grade, RT dosing, reRT fractionation regimen, time between primary and reRT, and reRT target volume, BVZ therapy was associated with significantly improved OS (2.51 [0.11, 4.92] months, P=.041) but no significant improvement in PFS (1.40 [-0.36, 3.18] months, P=.099). Patients receiving BVZ also had significantly lower rates of RN (2.2% vs 9.5%, P < .001). CONCLUSIONS Combination reRT+BVZ may improve OS and reduce rates of RN in recurrent HGG, but further controlled studies are needed to confirm these effects.