P14.08 Bevacizumab Treatment for the Lesion Emerging after the Radiotherapy for Malignant Glioma

Abstract BACKGROUND Because blocking vascular endothelial growth factor from reaching leaky capillaries is a logical strategy for the treatment, we reasoned that bevacizumab might be an effective treatment on recurrent malignant glioma and radiation necrosis (RN). In this study, the authors examined to differentiate RN from recurrent malignant glioma, and evaluated the results of bevacizumab treatment in each diagnosis. MATERIAL AND METHODS Four patients of malignant glioma (2 glioblastomas and 2 anaplastic astrocytomas), which demonstrated symptomatic lesion after radiotherapy, were involved in this study. All four patients were treated with bevacizumab on a 10 mg/kg biweekly (one cycle), for a total dose of 30 mg/kg (3 cycles) or furthermore. RN was differentiated from local recurrence in all four patients on the basis of 11C-methionine positron emission tomography and/or clinical course. Clinical evaluation and MRI studies were obtained after bevacizumab treatment in all cases repeatedly as possible. RESULTS Two patients were diagnosed as RN, and another two patients as tumor recurrence. Of the two patients with RN, neurological dysfunction was distinctly alleviated after bevacizumab treatment. Other two patients with tumor recurrence demonstrated no remarkable improvement in neurological dysfunction after bevacizumab treatment. Of all the two patients with RN, post-treatment MRI performed after the bevacizumab therapy showed a significant reduction of the massive lesion. CONCLUSION We concluded that bevacizumab could control the symptomatic massive lesion occurring after radiotherapy, and it might be more effective with the patients of RN, than with those of recurrent tumor.