Tamoxifen and raloxifene have been shown to reduce the risk breast cancer, but they can have their own risks and side effects. Tamoxifen and raloxifene are the only drugs that are approved in the US to help lower the risk of breast cancer, although for some women, drugs called aromatase inhibitors might be an option as well. This means that they act against (or block) estrogen (a female hormone) in some tissues of the body, but act like estrogen in others. Estrogen can fuel the growth of breast cancer cells. Tamoxifen can be taken whether or not you have gone through menopause, but raloxifene is only approved for post-menopausal women. Both of these drugs block estrogen in breast cells, which is why they can be useful in lowering breast cancer risk. To lower the risk of breast cancer, these drugs are taken for 5 years. The effect of these drugs on breast cancer risk has varied in different studies. When the results of all the studies are taken together, the overall reduction in risk for these drugs is about 40% (more than a third). These drugs lower the risk of both invasive breast cancer and ductal carcinoma in situ (DCIS). Although a medicine that cuts your risk by about 40% sounds like it must be a good thing, what it would really mean for you depends on how high your risk is in the first place (your baseline risk). Your risk of osteoporosis (bone thinning) can be affected by breast cancer treatment and other treatments that lower your oestrogen levels. Osteoporosis is thinning of the bones so that they become more brittle. Our bones start to thin after the age of 35 or so, as part of the natural ageing process. Any cancer treatment in women that lowers oestrogen levels can increase the risk of osteoporosis. These treatments include: Tamoxifen for breast cancer usually only reduces bone density by a small amount. In postmenopausal women, aromatase inhibitors increase bone loss at an average rate of 1 to 3% per year. In young women who have had ovarian suppression followed by aromatase inhibitor therapy, bone density is lost at an average of 7 to 8% per year. Treatment with tamoxifen for 2 to 5 years before having aromatase inhibitors may slow down the rate of bone loss. Women who have had an early menopause (before the age of 45) due to cancer treatment or who have ovarian suppression therapy and aromatase inhibitors are at higher risk of bone loss.
Raloxifene (Evista) belongs to a class of drugs called selective estrogen receptor modulators (SERMs). It is FDA-approved for the prevention and treatment of osteoporosis in postmenopausal women and to reduce risk of invasive breast cancer in postmenopausal women at high risk or with osteoporosis. SERMs were developed to reap the benefits of estrogen while avoiding the hormone's potential side effects. Raloxifene, a so-called ''designer'' estrogen, can act like estrogen on bone -- protecting its density -- but as an anti-estrogen on the lining of the uterus. In a three-year study involving some 600 postmenopausal women, raloxifene was found to increase bone density and lower LDL cholesterol, while having no stimulative effect on the uterine lining (which means that it is unlikely to cause uterine cancer). The first SERM to reach the market was tamoxifen, which blocks the stimulative effect of estrogen on breast tissue. Tamoxifen has proven valuable in preventing cancer in the second breast of women who have had cancer in one breast. If you've been diagnosed with hormone-receptive breast cancer (ER/PR ) - one that depends on estrogen to grow - join the crowd: about 70% of breast cancers are hormone-receptive. A drug currently used in the EU for relief of postmenopausal issues, including osteoporosis and osteopenia, has been found to stop the growth of breast cancer cells - even in women whose cancer has proved resistant to traditional treatments. Thankfully, there are effective drugs on the market to help prevent recurrence of these types of cancers: tamoxifen (for pre-menopausal women), and aromatase inhibitors (AIs) - Arimidex, Femara, and Aromasin - for those past menopause. Once active treatment has ended, women with ER /PR cancers generally undergo long-term hormone therapy, taking either tamoxifen or an AI for 5 to 10 years. These drugs have a proven track record of working to prevent recurrence: tamoxifen has been on the market for over 30 years, the AIs for more than a decade. By depriving cancer cells of estrogen, critical to their growth. Tamoxifen is a SERM (selective estrogen-receptor modulator). It works by blocking estrogen from attaching itself to the special receptors on cancer cells.
Will bazedoxifene be the new tamoxifen? Will it replace Arimidex? A drug currently used in the EU for relief of postmenopausal issues, including. Osteoporosis-related fractures affect approximately one in two white women and one in five white men in their lifetime. The impact of fractures includes loss of function, significant costs, and.