Bevacizumab combined with irinotecan or temozolomide in recurrent glioblastoma: a Turkish Oncology Group (TOG) study

Abstract

Purpose Given the lack of an effective systemic therapy for recurrent glioblastoma, this study aims to compare response rates, progression-free survival, overall survival, and toxicity profiles of bevacizumab in combination with temozolomide (TMZ) versus irinotecan. Methods We retrospectively analyzed patients with recurrent glioblastoma from seventeen oncology centers in T & uuml;rkiye who received bevacizumab combined with either TMZ or irinotecan after progression. Outcomes included response rates, progression-free survival (PFS), overall survival (OS), and adverse events assessed by CTCAE v4.0. Results Among 210 patients with recurrent glioblastoma, the median PFS was 7.9 months overall (5.2 months with TMZ-bevacizumab and 8.2 months with irinotecan-bevacizumab), and the median OS was 10.6 months overall (11.3 and 10.3 months, respectively). Six-month PFS and OS rates were 60% and 68% for the entire cohort, with no statistically significant differences between treatment regimens. Both combinations were generally well tolerated, with hypertension more frequent in the TMZ arm and liver enzyme elevation more common in the irinotecan arm. Conclusion In this multicenter cohort of patients with recurrent glioblastoma, bevacizumab combined with either temozolomide or irinotecan demonstrated comparable PFS and OS outcomes. Both regimens were generally well tolerated, suggesting that treatment choice may be guided by individual patient profiles and toxicity considerations rather than differences in efficacy.