Two breast cancer drugs have been tested head-to-head in high risk women. Both drugs reduced the risk of developing breast cancer, but tamoxifen was somewhat more effective than Evista. More than 19,000 women were followed for seven years. During the first five years, half took tamoxifen and the other half took Evista.
The long-term follow-up showed a 50% reduction in the risk of invasive breast cancer for women taking tamoxifen. Evista reduced the risk by 38%. Tamoxifen did have more side effects than Evista, however, including blood clots and a higher risk of uterine cancer. Relatively few women who could benefit from these drugs are taking either one of them. They work by blocking the effect of estrogen on breast tissue.
[The American Association of Cancer Research, April 19, 2010, Washington, DC.]
The People's Perspective on Medicine