RT-31 * SURVIVAL OUTCOMES IN PATIENTS RECEIVING BOTH FRACTIONATED STEREOTACTIC RADIOTHERAPY AND BEVACIZUMAB FOR RECURRENT HIGH GRADE GLIOMA

Abstract

BACKGROUND: Fractionated stereotactic radiotherapy (FSRT) and bevacizumab (BEV) are commonly utilized treatments for recurrent high grade glioma (rHGG), yet robust outcomes data regarding the combination of these therapies is lacking. Furthermore, the optimal sequence of these regimens is not well defined. METHODS: Patients with WHO grade III (AA) or IV (GBM) glioma who received both BEV and re-irradiation with FSRT were retrospectively reviewed. Study endpoints included overall survival (OS) and median survival time (MST) from recurrence. Kaplan-Meier curves were generated utilizing a log-rank test with a p-value of ≤0.05 considered significant. RESULTS: 105 patients with rHGG (GBM = 79, AA = 26) received both BEV and FSRT. Patient characteristics at recurrence were as follows: Median KPS was 80 (range: 50-100); median age was 57; median time to recurrence was 10.8 months (mo) and 36.2% of patients had surgery for recurrence. The median time to second treatment modality was 6.2 mo for patients receiving BEV first and 5.5 mo for the FSRT first cohort. For all patients, median OS was 28.1 mo and MST from recurrence was 14.7 mo (25.2 mo and 13.8 mo for GBM only). In patients receiving FSRT first (n = 56), median OS and MST from recurrence were 35.1 mo and 16.3 mo respectively. In patients receiving BEV first (n = 50), median OS and MST from recurrence were 25.9 and 13.3 mo respectively. Sequencing FSRT prior to BEV at recurrence showed improvement in OS (p = 0.043) but only a trend for improvement in MST from recurrence (p = 0.116). CONCLUSIONS: The combination of FSRT and BEV for recurrent/progressive HGG provide promising results in terms of OS and survival from recurrence. Combining these treatment modalities appears to improve upon the historic outcomes of either treatment alone and sequencing FSRT as the initial treatment of recurrence may provide a survival benefit.