Patients whose breast cancer is fueled by the hormones estrogen or progesterone are often treated with therapies that cut off or reduce the body’s supply of these hormones. This can be accomplished by surgery to remove the ovaries, which produce estrogen and progesterone, or through drugs such as Lupron or Zoladex, which shut down estrogen and progesterone production in the ovaries.
Ovarian suppression is an option only for women who have yet to enter menopause. Postmenopausal women naturally have much lower levels of circulating estrogen and progesterone, because their ovaries make much less of the hormones. (Menopause doesn’t cause estrogen levels to drop to zero because fat cells still produce small amounts of it.)
Cutting estrogen levels causes menstrual periods to stop. If drugs are used to suppress ovary function, menstrual periods may resume when the drug therapy is stopped. For patients who undergo ovary-removal surgery, however, the procedure leads to early menopause.
Sometimes, ovarian suppression therapy is combined with other treatments, particularly in younger, premenopausal women with a high risk of breast cancer recurrence. These other treatments include tamoxifen, a drug used as standard treatment for premenopausal women with hormone-driven breast cancer, or aromatase inhibitors, which prevent hormones from being converted into estrogen.
Some women who have been treated with chemotherapy and remain premenopausal may be treated with a combination of tamoxifen and ovarian suppression to reduce the chances that breast cancer will recur.