Tamoxifen and raloxifene for the prevention of breast cancer

There are two primary strategies for the prevention of breast cancer using targeted antiestrogens. The first strategy is direct and uses tamoxifen treatment for 5 years in high risk women. The second strategy exploits the known target site specific effect of antiestrogens to preserve bone density (ie: act as an estrogen) while acting as an antitumor agent in the breast. The second strategy is indirect and we refer to it as the Trojan horse strategy. By using a selective estrogen receptor modulator to prevent osteoporosis a beneficial side effect will be the prevention of breast cancer in women without risk factors. Raloxifene is an example of the first medicine to exploit this Trojan horse strategy.