Estrogen taken alone has been linked to cancer of the endometrium. However, this risk may be decreased by giving progestin with estrogen, as well as by reducing the dose of estrogen given. On the other hand, there is some question about the role of progestin in heart disease. While estrogens help reduce the risk, it is not known whether progestins may block some of the effect of the estrogen. Discuss these issues, as well as questions about dosage and hormone combinations, with your doctor.
Most studies suggest no link between hormone replacement therapy and breast cancer.
Some studies, though, indicate that a woman's chances of developing breast cancer increase a small amount if she has been on hormones for more than 10 years by as much as 20 percent. Like other women their age, women taking replacement hormones should have regular breast exams and mammograms. Although many women who take hormones don't notice any side effects, they do occur in some women. Although most women benefit from taking estrogens, not every woman can take them. If you have had breast cancer, endometrial cancer, or liver disease, estrogen often is not recommended unless your symptoms are so severe that you feel the benefit from taking it is greater than the risk.