Prognostic role of angiogenesis in colorectal cancer

The need for dependable prognostic markers in colorectal cancer, both in the advanced as well the as adjuvant setting, is greater than ever. The introduction of new chemotherapeutic agents in the clinic, with different mechanisms of action as well as different side-effect profiles, has made this even more important. Angiogenesis, the formation of new vessels, is essential for tumour growth and metastasis. The adverse impact of tumour angiogenesis in the context of colorectal cancer on relapse and prognosis has been evaluated in numerous retrospective studies. Most of these studies have tended to be relatively small in terms of patient numbers and sometimes have reached conflicting conclusions. A number of different angiogenic factors, including vascular endothelial growth factor (VEGF), thymidine phosphorylase (TP) and intratumoural microvessel density (IMD), have been assessed to varying extents. This article highlights some of the important developments in this rapidly expanding field.