Clinical Outcomes of Dose Escalated Re-Irradiation in Patients with Recurrent High Grade Glioma

Abstract Background Reirradiation for recurrent gliomas is a controversial treatment option with no clear standard dose or concurrent systemic therapy. Methods This series represents a single institution retrospective review of patients treated with re-irradiation for recurrent high grade glioma. After 2012, patients were commonly offered concurrent bevacizumab as a cytoprotective agent against radiation necrosis. Kaplan Meier method was used to estimate overall and progression-free survival. Cox proportional hazards regression was used to identify factors associated with overall and progression-free survival. Results Between 2001 and 2021, 52 patients underwent re-irradiation for a diagnosis of recurrent high grade glioma. 36 patients (69.2%) had a histologic diagnosis of glioblastoma at time of re-irradiation. The median BED10 (biologic equivalent dose 10 Gy) of re-irradiation was 53.1 Gy . Twenty-one patients (40.4%) received concurrent bevacizumab with re-irradiation. Median survival for the entire cohort and for glioblastoma at time of recurrence patients was 6.7 months and 6.0 months , respectively. For patients with glioblastoma at time of recurrence, completing re-irradiation (HR 0.03, p < 0.001), use of concurrent bevacizumab (HR 0.3, p=0.009), and the BED10 (HR 0.9, p=0.005) were predictive of overall survival. Nine patients developed Grade 3-5 toxicity; of these, 2 received concurrent bevacizumab and 7 did not (p=0.15). Conclusion High dose re-irradiation with concurrent bevacizumab is feasible in patients with recurrent gliomas. Concurrent bevacizumab and increasing radiation dose may improve survival in recurrent glioblastoma patients.