Prognostic significance of the microvascular count in colorectal cancer

To investigate the potential correlations between a high microvascular count and the survival rate in colorectal cancer.

Three markers for endothelial cells--Ulex Europaeus Lectin (UEA), a polyclonal anti-von Willebrand factor (vWF) antibody, and a monoclonal anti-CD31 antibody (all from Dakopatts, Glostrup, Denmark)--were used for immunohistochemical detection of microvessels in whole-mount sections from 15 colorectal cancers. Areas with higher microvascular density were homogeneously distributed in the sections, regardless of the marker used. The anti-vWF antibody was subsequently used for quantification of microvessels in full-cross tumor biopsies collected from 212 consecutive surgical specimens. The correlations between the mean number of microvessels in areas with the highest microvascular density and tumor differentiation, tumor stage according to Dukes', and survival time were investigated.

A significantly longer survival time was shown for patients who had tumors with a mean of more than 10 anti-vWF-positive microvessels, as compared with those who had < or = five. Tumors with a microvascular count between six and 10 microvessels behaved in-between. There was no correlation between the number of microvessels and tumor differentiation or Dukes' stage.

The number of microvessels measurable in tumor biopsies seems to be a prognostic predictor independent of Dukes' stage in colorectal cancer. However, our results are opposite to the findings in other tumor types investigated so far; we found that a high microvascular count predicted a longer survival time, rather than a shorter one. Determination of the microvascular count can be of importance in therapy selection even before, or immediately after, surgery, ie, before Dukes' stage is known.