If you have not gone through menopause, your ovaries still make most of your estrogen. After menopause, your ovaries no longer make large amounts of estrogen. But cells in your muscles and fat still make some estrogen from male hormones called androgens.
Aromatase inhibitors interfere with the enzyme called aromatase. Its role is to convert androgens into estrogen. By affecting how much estrogen is made, aromatase inhibitors reduce estrogen in the body. This helps slow or stop the growth of breast tumors that are sensitive to estrogen. Sometimes it even shrinks them. Researchers have found that the medicines can’t lower estrogen levels enough to affect tumor growth in younger women who have not gone through menopause. That’s because younger women’s ovaries still make high levels of estrogen. For this reason, these medicines are used only in women who have gone through menopause.
There are 3 aromatase inhibitors used for breast cancer, all taken as pills:
Many studies have compared aromatase inhibitors with tamoxifen as adjuvant hormone therapy in postmenopausal women. Using these medicines, either alone or after tamoxifen, has been shown to better reduce the risk of cancer recurrence than using only tamoxifen for 5 years.