Non-invasive methods of assessing angiogenesis and their value in predicting response to treatment in colorectal cancer

Background: Tumour neoangiogenesis can be assessed non-invasively by measuring angiogenic cytokine concentrations in peripheral circulation and by dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI). The aim of this study was to assess whether these methods can predict and monitor response to treatment in patients with rectal cancer treated with preoperative chemoradiotherapy. Methods: Serum and plasma vascular endothelial growth factor levels were measured in 31 patients with T-3/T-4 rectal cancers before quantitating tumour permeability (1n K-trans) by DCE-MRI Sixteen patients receiving preoperative chemoradiotherapy had serial vascular endothelial growth factor (VEGF) and DCE-MRI measurements. Response to treatment was assessed using World Health Organization criteria. Results: Serum VEGF and 1n K-trans correlated before treatment (r = 0.48, P = 0.01). Responsive tumours (n = 8) had higher pretreatment permeability values than non-responsive tumours (n = 8) (mean 1n K-trans - 0.46 and - 0.72 respectively; P = 0.03). Compared with pretreatment values, responsive tumours showed a marked reduction in permeability at the end of treatment (mean 1n K-trans -0.46 and -0.86 respectively; P = 0.04). Pretreatment serum VEGF levels were not statistically different between the two groups. Conclusion: Rectal rumours with higher permeability, at presentation appear to respond better to chemo radio therapy than those of lower permeability. This may allow preselection of appropriate rumours for these regimens, with patients with low-permeability tumours being considered for alternative therapies.