1Radiation Medicine Program,
ADC can monitor early tumor response to cytotoxic therapy and predict clinical outcomes. This study monitored early ADC response and tumor growth following sunitinib and/or radiotherapy in a murine intracranial model of human glioblastoma multiforme. Imaging proceeded at 3-7 day intervals following base-line MRI and image-based stratification into treatment arms. RT trial arms demonstrated considerable early ADC elevation, and persistent elevation during growth delay. Sunitinib monotherapy maintained ADC below other arms, and constrained tumor growth. Control animals displayed moderate ADC elevation and earliest exponential tumor growth. Early ADC changes may be a useful biomarker of treatment response and growth delay.