Tumor angiogenesis as a prognostic factor in ovarian carcinoma: quantification of endothelial immunoreactivity by image analysis.

BACKGROUND: The growth of a malignant tumor requires the formation of new capillaries. Quantification of these microvessels is difficult. The purpose of this study was to establish an objective technique for quantifying angiogenesis and to evaluate whether microvessel quantity may predict tumor aggressiveness in patients with ovarian carcinoma.
METHODS: Endothelial area was used to quantify microvessel density in immunohistochemically stained sections of 28 International Federation of Gynecology and Obstetrics Stage IIIC ovarian carcinomas. The endothelial area was measured with a computer-aided image analysis system in the subepithelial stroma of highest vascularization. The endothelial area in the specimens of 14 patients who survived for > or =6 years was compared with that of 14 patients matched for stage and treatment who died of the disease.
RESULTS: The mean tumor area analyzed was 5.04 +/- 0.23 mm2. The mean endothelial area per mm2 of stroma from survivors and dead patients was 0.038 +/- 0.026 mm2 and 0.110 +/- 0.034 mm2, respectively (P < 0.0001). No significant differences were found in histology, tumor grade, status of lymph nodes, and amount of residual tumor.
CONCLUSIONS: Image analysis was used to overcome the potential subjectivity of manual counts. Computer-assisted image analysis can evaluate accurately the angiogenic potential in ovarian carcinomas. Tumor angiogenesis may prove to be a prognostic factor in patients with ovarian carcinoma. This study suggests that the measurement of the endothelial area would be clinically useful in determining microvessel density [See editorial on pages 2219-21, this issue.]