Vascular and metabolic response to bevacizumab-containing regimens in two patients with colorectal liver metastases measured by dynamic contrast-enhanced MRI and dynamic 18F-FDG-PET

D. Vriens, L. de Geus-Oei, A. Heerschap, H. van Laarhoven and W. Oyen

Department of Nuclear Medicine, Radboud University Nijmegen Medical Centre, the Netherlands.
Mar, 2011



Early monitoring of response to treatment is one of the cornerstones of personalized treatment. As new and often expensive targeted therapies, which are tumoristatic rather than tumoricidal, become available, new demands are posed on response assessment. Bevacizumab, an antiangiogenic agent causing normalization of the tumor microvasculature, potentiates the effect of cytotoxic agents on colorectal liver metastases. It is known that assessment of glucose metabolism by (dynamic) positron emission tomography using [(18)F]-2-fluoro-2-deoxy-D-glucose ((18)F-FDG PET) can be used as an early surrogate endpoint to determine treatment efficacy. Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) can be used to quantify functional tumor vasculature (permeability, vascular surface area). Here, we describe the response of colorectal liver metastases to cytotoxic regimens including bevacizumab using both (18)F-FDG PET and DCE-MRI in 2 cases. In both cases, a large reduction in glucose metabolic rate and functional tumor vasculature are observed after 3 treatment cycles.