Glioblastoma Re-Irradiation: Impact of Concomitant Bevacizumab - Retrospective Series of 61 Cases

Purpose: Glioblastoma is the most common primary brain tumor with a poor prognosis. Although the standard of initial treatment is well defined, no recommendation exists in the relapse setting. This work focuses on the optimal strategy for recurrent glioblastoma. Methods: We performed a retrospective monocentric analysis of all recurrent glioblastoma adult patients treated since 2000 in one neuro-oncology center by re-irradiation, alone or combined with chemotherapy and/or surgery at first or second relapse. Results: Overall, 61 patients underwent a re-irradiation for glioblastoma relapse. Patient median age at diagnosis was 55 (27 to 76), 44% were women. At diagnosis, 77% underwent surgical resection and 23% were biopsied. Most of them (95%) received a Stuppregimen. After a median follow-up of 31.1 months, 44 patients (72%) had died and the median overall survival (mOS) was 39.8 months. Regardless of the time of treatment (first or second relapse), patients treated with radiation therapy concomitant to bevacizumab (RTbev, n=36) showed superior survival data compared to patients treated with radiation therapy alone (RTalone, n=17). At first relapse, median progression free survival (mPFS) of RTbev (n=19) was 9.9 versus 3.6 months for RTalone (n=6) (OR=3.98 (3.14-61.81); p=0.001). At second relapse, mPFS of RTbev (n=17) was 9.2 versus 5.4 months for RTalone (n=11) (OR=2.31 (1.18-7.75); p =0.03), and mOS of RTbev was 15.2 versus 9.1 months for RTalone (OR=3.60 (2.17-18.13); p=0.001). Conclusion: This retrospective monocentric analysis reports a favorable impact of bevacizumab adjunction to re-irradiation. The high mOS may be due to patient selection, but emphasis the relevance of a multidisciplinary approach.