In the past, many women used menopausal hormone therapy (MHT), also known as hormone replacement therapy, to relieve hot flashes and other symptoms of menopause. But studies show that use of estrogen plus progestin increases the risk of both developing and dying from breast cancer. Although MHT is approved for the short-term relief of menopausal symptoms, the U.S. Food and Drug Administration (FDA) recommends women use only the lowest dose that eases symptoms for the shortest time needed.
When women take these hormones (estrogen plus progestin), their risk of having an abnormal mammogram increases within the first year of use and their risk of breast cancer increases within the first five years of use. The risk of breast cancer goes up slightly each year a woman takes estrogen plus progestin. One large study found women who use estrogen plus progestin for five or more years (and are still taking it) more than double their breast cancer risk.
When women stop taking MHT, the risk of breast cancer starts to decline. After about 5 to 10 years, the risk returns to that of a woman who has never used MHT.