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 T3/T4 rectal cancers before quantitating tumour permeability (ln Ktrans) 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 ln Ktrans 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 ln Ktrans - 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 ln Ktrans - 0.46 and - 0.86 respectively; P = 0.04). Pretreatment serum VEGF levels were not statistically different between the two groups.

Conclusion: Rectal tumours with higher permeability at presentation appear to respond better to chemoradiotherapy than those of lower permeability. This may allow preselection of appropriate tumours for these regimens, with patients with low-permeability tumours being considered for alternative therapies.