Purpose: To investigate the potential correlations between a high micr
ovascular count and the survival rate in colorectal cancer. Materials
and Methods: Three markers for endothelial cells-Ulex Europaeus Lectin
(UEA), a polyclonal anti-van Willebrand factor (VWF) antibody, and a
monoclonal anti-CD31 antibody(all from Dakopatts, Glostrup, Denmark)-w
ere used for immunohistochemical detection of microvessels in whole-mo
unt sections from 15 colorectal cancers. Areas with higher microvascul
ar density were homogeneously distributed in the sections, regardless
of the marker used. The and-vWF antibody was subsequently used for qua
ntification of microvessels in full-cross tumor biopsies collected fro
m 212 consecutive surgical specimens. The correlations between the mea
n number of microvessels in areas with the highest microvascular densi
ty and tumor differentiation, tumor stage according to Dukes', and sur
vival time were investigated. Results: A significantly longer survival
time was shown for patients who had tumors with a mean of more than 1
0 anti-vWf-positive microvessels, as compared with those who had less
than or equal to five. Tumors with a microvascular count between six a
nd 10 microvessels behaved in-between. There was no correlation betwee
n the number of microvessels and tumor differentiation or Dukes' stage
. Conclusion: The number of microvessels measurable in tumor biopsies
seems to be a prognostic predictor independent of Dukes' stage in colo
rectal cancer. However, our results are opposite to the findings in ot
her tumor types investigated so far; we found that a high microvascula
r count predicted a longer survival time, rather than a shorter one. D
etermination of the microvascular count can be of importance in therap
y selection even before, or immediately after, surgery, ie, before Duk
es' stage is known. (C) 1996 by American Society of Clinical Oncology.