P17.83 OUTCOMES OF RECURRENT GLIOBLASTOMA PATIENTS TREATED WITH BEVACIZUMAB AT A TERTIARY CARE CENTER

BACKGROUND: Bevacizumab is FDA approved for use in recurrent glioblastoma (rGBM). There is limited information on outcomes of rGBM treated with bevacizumab at tertiary care hospitals. We evaluated the progression-free survival (PFS) and overall survival (OS) in rGBM patients treated with bevacizumab at our center. We also examined the outcomes of patients with rGBM treated with bevacizumab in first recurrence, second recurrence or third or greater recurrence to see if there was a PFS or OS survival difference (three groups). METHODS: With IRB approval, the Cleveland Clinic Brain Tumor database was used to examine 690 rGBM patient charts (2003 to 2013). The patients that received bevacizumab for rGBM were included for this analysis. Progression-free survival and OS was calculated using Kaplan-Meier analysis and the Renyi (supremum log-rank) test to formally compare the difference in overall and PFS between the three groups. All analyses were completed in R version 3.0.1. RESULTS: One hundred and fifty patients received bevacizumab for rGBM. The median age 56 years (range: 24-83). Median KPS prior to initiation of bevacizumab treatment was 80 (range: 40-100). Twenty-eight patients had multifocal and 122 had unifocal disease at time of starting bevacizumab therapy. The median number of comorbidities at diagnosis was1 (range: 0-4). Seventy five patients (50%) received bevacizumab at first recurrence, 50 patients (33%) started bevacizumab at second recurrence, and 25 patients (17%) were treated with bevacizumab at third or later recurrences. Median OS from start of bevacizumab was 12.2 months (95% CI: 10.0, 14.3) and median PFS was 8.3 months (95% CI: 6.2, 10.2). Stratified by recurrence and initiation of bevacizumab, median PFS was 7.1 months (95% CI: 5.9, 10.1) for the first recurrence, 9.9 months (95% CI: 6.3, 25.2) for second recurrence, and 9.4 months (95% CI: 3.8, 16.8) for the third recurrence (p = 0.09). Median OS was 11.7 months (95% CI: 10.3, 14.3) for first recurrence, 10.0 months (95% CI: 8.1, 39.3) for second recurrence, and 13.9 months (95% CI: 8.2, 18.4) for the third or later recurrence (p = 0.26). CONCLUSIONS: The benefit seen with bevacizumab in our cohort is consistent with that reported in other studies. There was no significant difference in median OS or PFS in the patients with rGBM groups treated with bevacizumab in first, second or third or later recurrence. One hypothesis is that patients who need bevacizumab at first recurrence possibl