SERMs are called "selective" because they bind to particular estrogen receptors. This selective binding action is sometimes called estrogen inhibition, or estrogen suppression. SERMs do not prevent the production of estrogen, but they help to slow or stop the growth of estrogen-sensitive cancer cells by starving them of a full dose of natural estrogen.
These drugs, like many adjuvant breast cancer therapies, have benefits and risks. While they help prevent a recurrence of estrogen-receptor positive breast cancer, they also:
- stimulate your liver cells, and lower your cholesterol levels
- protect bone health for post-menopausal women, keeping bones strong and preventing breaks and fractures
- endometrical thickening, raising your risk of uterine cancer
- menopausal symptoms (hot flashes, vaginal dryness, low libido)
There are three SERMs currently available:
- Tamoxifen, the first SERM to be used as an anticancer drug
- Evista (raloxifene), intended to treat osteoporosis, but effective at reducing the risk of breast cancer
- Fareston (toremifene), which as of 2008, was just starting to be used in the U.S.
National Cancer Institute. Understanding Cancer Series: Estrogen Receptors/SERMs. Last updated: 09/01/2006.