For thousands of women, hormonal therapy (not to be confused with hormone replacement therapy used for the treatment of symptoms associated with menopause) is the recommended course of action in order to treat hormone-receptor-positive breast cancers. Estrogen causes these types of breast cancers to grow. Most of the estrogen produced in women’s bodies comes from the ovaries. Blocking the estrogen flow from the ovaries or lowering the amount of estrogen within the body has been proven to shrink the cancer, as well as reducing the chances of it coming back. In some cases, the ovaries and fallopian tubes are surgically removed, while for other women, hormonal therapy medicines (such as aromatase inhibitors, selective estrogen receptor modulators and estrogen receptor downregulators) are used.