However, the debate is whether there is low risk or very low risk. Metaanalyses have estimated risks of about 1.3 to 1.5, and these are only after taking estrogen for longer than ten years. The risk of developing breast cancer is higher than the risk of dying from it. The most recent studies suggest that the mortality from breast cancer is lower in women who were taking estrogen. It is not known if this is a biological effect or whether women taking estrogen were more vigilant in getting mammograms.
Breast cancer is a frightening disease and even a tiny increased relative risk is important.
Also, women develop this disease at a younger age than coronary artery disease and osteoporosis. But many women do not realize that the risk of breast cancer is high whether or not they take estrogen. The potential for exploiting the newly described estrogen receptor action by drugs that selectively enhance estrogen action at the bone and lipids level but are anti-estrogen at the breast and endometrium will soon be available. This type of cancer has a high cure rate with hysterectomy. Although some women may be willing to accept these risks, most physicians are not, and progesterones are prescribed with estrogens unless the woman has already has a hysterectomy.