It can, but this depends largely on how long you take the estrogen replacement therapy (ERT).
Because estrogen use raises the incidence of uterine cancer, the use of estrogen alone is prescribed primarily for the reduction of menopausal symptoms (such as a reduction in hot flashes and prevention of osteoporosis) in post-menopausal women who no longer have a uterus.
However, the Breast Cancer Demonstration Project found that women's risk of breast cancer went up by about 1% percent for every year that they took estrogen alone. The risk with ERT is prolonged use -- the longer a woman uses ERT, the greater her risk. This increase in risk of breast cancer begins to drop after estrogen use stops and eventually returns to that of women who have never used estrogen.
Therefore, women should not take ERT for prolonged periods of time. When ERT is used, it is prescribed at the lowest effective dose for the shortest period of time.
Furthermore, if a woman is going to receive ERT, she may have a lower risk of heart disease as a side effect if the ERT is initiated at the beginning of menopausal symptoms, rather than later in life.
There are many wonderful alternatives that can help women alleviate undesired symptoms of menopause, without increasing her risk of breast cancer or other diseases. These alternatives include natural hormone replacements, lifestyle changes, and dietary modification.