A morphometric study of neovascularization in colorectal carcinoma

Neovascularization reportedly is correlated with metastasis, recurrence, and prognosis in some types of tumors. Microvessel quantification in so-called "hot spots" has been studied extensively as the only factor reflecting angiogenesis in various malignant tumors. The objective of this report was to evaluate multiple morphometric microvascular characteristics in addition to microvessel density (MVD) in colorectal carcinomas to provide a better approach to examining the relation between angiogenesis and clinicopathologic factors and prognosis.

Histologic sections from 106 colorectal adenocarcinomas and 17 adenomas, immunostained for factor VIII, were evaluated by image analysis for the quantification of MVD, total vascular area (TVA), and microvascular branching, as well as several morphometric parameters related to the vessel size or shape.

MVD gradually decreased with progressing Dukes stage. The vascular branching counts were significantly higher in carcinomas than in adenomas, and remained unaffected through progressing Dukes stages. Shape-related parameters showed significant differences between carcinomas and adenomas and between different grades of differentiation. Branching counts and TVA were the only factors found to be of prognostic significance.

This study provides evidence that neovascularization is an early critical event in colorectal tumorigenesis, reaching a maximum level early in the malignant process. Its prognostic significance is better assessed by quantification of TVA and the branching pattern of microvessels, whereas MVD does not provide significant prognostic information for colorectal carcinoma patients.