Clinical importance of the determination of tumor angiogenesis in breast carcinoma: much more than a new prognostic tool.

PURPOSE: To review prognostic and therapeutic applications of angiogenesis research in breast carcinoma. METHODS: We reviewed the (1) biologic role of angiogenesis, particularly in transformation, progression, and metastasis of breast cancer; (2) methods to detect angiogenic activity in human pathology; (3) clinical studies relating clinical outcome of patients with breast cancer to the assessment of angiogenesis; (4) predictive value of angiogenesis for response to anticancer therapies; and (5) pharmacologic characteristics of current antiangiogenic drugs. RESULTS: There is mounting evidence that angiogenesis plays a relevant role in the biologic aggressiveness of breast cancer. Using either immunohistochemical or biochemical methods, several studies have shown a worse prognosis for those patients with tumors with high angiogenic activity. In some studies angiogenesis has an independent prognostic value. The most promising angiogenic inhibitors are under early-phase clinical evaluation in patients with tumors resistant to conventional therapies. Novel therapeutic strategies for breast cancer patients are presented and discussed. CONCLUSION: The majority of the retrospective studies show that angiogenesis is an important new prognostic indicator in early-stage breast carcinoma. This marker should be evaluated in prospective controlled clinical trials to demonstrate whether adjuvant therapies may improve the prognosis of those patients at high risk, eg, those with highly vascularized tumors. Since invasive breast carcinoma has a well defined stromal vascular component and produces angiogenic factors, it seems reasonable to postulate that this tumor may be one of the most responsive to angiogenesis inhibitors given alone or in combination with conventional anticancer treatments.