Women who are at increased risk for breast cancer can be easily identified in clinical practice and may have very high lifetime probabilities of developing invasive breast cancer. Nelson and colleagues conducted a meta-analysis of eight clinical trials that examined the ability of selective oestrogen receptor modulators (SERMs) or tibolone to reduce the risk of invasive breast cancer in both premenopausal and postmenopausal women at various levels of risk of breast cancer. Tamoxifen and raloxifene are associated with a significant reduction in the risk of oestrogen receptor-positive invasive breast cancer. Tamoxifen is effective in both younger and older women, although side effects increase with age.

The authors state that data are lacking on doses, duration, timing and long-term side effects, although this statement is not entirely accurate. While it is true that only 20 …