[Is there a basis for prevention of breast cancer with drugs?]

The anti-oestrogen drug tamoxifen has led to one of the most important improvements in therapy for breast cancer patients achieved during the last decades. Tamoxifen reduces risk of relapse and improves survival in women with breast cancer. In addition, tamoxifen has favourable effects on the lipoprotein metabolism, reduces morbidity and death from myocardial infarction, and stabilizes bone density in women after menopause. Owing to the good therapeutic results in breast cancer patients and the additional favourable effects of tamoxifen, studies were started among healthy women with elevated risk of breast cancer. The intention was to examine whether tamoxifen could reduce the risk of breast cancer development in healthy women. Recent studies, however, have demonstrated higher risk of endometrium cancer in breast cancer patients treated with tamoxifen, and higher risk of histological abnormalities in the endometrium in healthy women. Prevention trials, when tamoxifen is given to healthy women, are disputed, owing to the apparent carcinogenic effect of tamoxifen.