Prevention of breast cancer: the case for studying inhibition of IGF-1 actions.

Measures to prevent breast cancer are receiving particular attention by women at high risk from either clinico-pathologic findings or genetic susceptibility. Life-style and nutritional interventions have been difficult to quantify, but merit further study. Chemoprevention with tamoxifen and subsequently with the related raloxifene demonstrates some efficacy, but may be not be applicable to premenopausal women (with regard to raloxifene), or have low acceptance (with regard to tamoxifen). Based on the importance of the insulin-like growth factor-1 pathway in mammary gland development, and the availability of a potent inhibitor, pilot studies are ongoing to evaluate such an inhibitor in women with demonstrable high risk to develop breast cancer. Short-term interventions with the inhibitor have been completed, and subsequent interventions are planned.