Tumor angiogenesis and outcome in osteosarcoma.

Intratumoral angiogenesis quantified by microvessel density (MVD) has been shown to be a strong prognostic indicator in a number of malignant tumors. Its association with prognosis in bone sarcomas has been subject to less extensive research. The aim of this study was to investigate prognostic significance of angiogenesis in osteosarcoma. Thirty-nine patients with osteosarcoma were included in a retrospective immunohistochemical study. Sections from diagnostic biopsies were immunostained using anti-von Willebrand factor antibody and microvessels were counted at 400 x magnification on 3 microscopic fields per patient. MVD was correlated with overall and disease-free survival by Kaplan-Meier and log-rank analysis. Correlation between clinicopathological variables and the degree of angiogenesis was tested using a chi 2 test. Significant statistical difference was found regarding overall survival and disease-free survival between patients with high (> 32.3 vessels/field) and low (< or = 32.3 vessels/field) microvessel counts (log-rank test p = .0196 and p = .0147, respectively). The rate of metastasis was significantly higher in patients with high microvessel counts (p = .042). These findings strongly suggest that angiogenesis quantified by microvessel density is predictive of metastasis and poor prognosis in osteosarcoma.