Angiogenic Index: A New Method for Assessing Microvascularity in Breast Carcinoma with Possible Prognostic Implications.

The quantitation of microvessels in breast cancer in sections immunolabeled for factor VIII, CD-34, or CD-31 currently is expressed as numbers of vessels/mm2. In an attempt to perform a more accurate method for counting microvessels, we determined the number of microvessels by 1,000 tumor cells (angiogenic index; AI). This new method minimizes the possible variations concerning the width of the microscopic fields, stroma/epithelium relations, and cellular tumor size. The present study compares the number of vessels determined by the traditional method (vessels/mm2) and AI in a series of 215 cases of ductal infiltrating carcinoma not otherwise specified. Also we studied the degree of correlation between both methods and with pathologic variables (tumor size, histologic grade, mitotic count, tumor necrosis, vascular invasion, skin infiltration, and axillary lymph node metastasis). Our results showed that the AI correlates more significantly than the classic microvessel density determination with other prognostic factors in breast cancer. In histologic grade III tumors, high AI correlates significantly with the presence of more than three axillary lymph nodes metastases. Therefore we recommend determining the degree of tumor angiogenesis by counting vessels per 1,000 tumor cells (AI) because of its reliable determination and significant correlation with other prognostic factors.