P16.24MULTIMODAL IMAGING ELUCIDATES PHYSIOLOGICAL AND METABOLIC CHANGES INDUCED BY ANTI-ANGIOGENIC THERAPY IN GLIOBLASTOMA

Treatment of primary and recurrent glioblastoma with anti-angiogenic therapies, either alone or in combination with chemotherapy, fails to extend overall survival, despite the often reported improvements in progression free survival and patient health condition. To improve the efficacy of these therapies, a better understanding of the mechanisms of tumour adaptation and treatment escape is warranted, while at the same time adopting imaging protocols that evaluate tumour progression without ambiguity. The complementary roles of Magnetic Resonance Imaging and Positron Emission Tomography can help to elucidate the physiologic and metabolic changes induced by anti-angiogenic agents, and better appreciate the clinical response at early stages of the treatment. In the present study, we have used this multi-modal imaging approach to investigate the changes induced by bevacizumab in pre-clinical models of glioblastomas obtained from patient-derived biopsies. We report longitudinal changes in vascular morphology and function, and describe how the changes in blood supply lead to increased intratumoral hypoxia, resulting in high glycolytic activity and tumour invasiveness.