Bevacizumab therapy in recurrent high grade glioma: Impact on local control and survival

Abstract

13000 Background: Anti-angiogenic agents have recently shown impressive radiological responses in high grade glioma. However, it is not clear if the responses are related to vascular changes or due to anti-tumoral effect. We report the mature results of a retrospective study of bevacizumab based therapy in recurrent high grade gliomas. Methods: Fifty four patients with recurrent high grade gliomas received therapy with Bevacizumab at 10 mg/kg every two weeks for four doses in an 8 week cycle along with Irinotecan at 125 mg/m2. Treatment evaluation was done with neurological examination, conventional magnetic resonance and perfusion imaging subsequently. The survival was calculated from the time of starting bevacizumab based therapy. Results: The median progression free survival (PFS) and overall survival (OS) were 5 (95% confidence interval, 1.0–6.9) and 9 (95% confidence interval, 7.5–10.5) months respectively. Radiological responses following therapy were noted in 72.2% of cases. The Patients who received > 2 cycles of bevacizumab based therapy had a PFS and OS of 7 and 11 months compared to 3.5 and 5 months for the patients who received < 2 cycles of therapy (p=0.02 and P<0.0001) respectively. Neither the grade of the tumor nor the surgical resection prior to therapy had an impact on survival. Although the predominant pattern of relapse was local, twelve patients (22.2%) failed as diffuse disease. Conclusion: Bevacizumab therapy improves the survival in recurrent high grade glioma. A possible change in the invasiveness of the tumor following therapy is worrisome and needs to be closely monitored. No significant financial relationships to disclose.