According to an article recently published in the New England Journal of Medicine, Evista® (raloxifene) is associated with some serious side effects, such as stroke and blood clots, among postmenopausal women with existing heart problems or those at risk for developing heart problems. However, since these side effects remain low overall, patients may wish to discuss the benefits (including a reduction in the risk of developing breast cancer and bone fractures) and risks of Evista with their physician.
Breast cancer is accountable for approximately 40,000 deaths annually in the U.S. alone. The majority of women with breast cancer have cancer that is estrogen-receptor positive (ER-positive). This type of breast cancer is stimulated to grow by the female hormones estrogen and/or progesterone.
Women with ER-positive breast cancer are commonly treated with hormone therapy. This approach suppresses the formation of estrogen or blocks estrogen from stimulating cancer cells to grow.
Some postmenopausal women at a high risk of developing breast cancer can be treated with the anti-estrogen agent tamoxifen. Results from studies have indicated that tamoxifen can reduce the risk of developing breast cancer in these high-risk women by approximately 50%.
Recent results from a large trial have indicated that raloxifene, also an agent that reduces the stimulatory effects of estrogen on cancer cell growth, appears to reduce the risk of developing breast cancer equally as well as tamoxifen in postmenopausal women who are considered at a high risk of developing the disease. However, raloxifene appears to have significantly fewer serious side effects than tamoxifen.
Researchers recently conducted a trial to evaluate potential risks with raloxifene when used among postmenopausal women with coronary heart disease (CHD) or those at risk for developing CHD. This trial included over 10,000 postmenopausal women who were treated with either raloxifene or placebo (inactive substitute) for approximately six years.
- The use of raloxifene reduced the risk of developing breast cancer among these women by nearly half (44%).
- The use of raloxifene reduced the risk of bone fractures of the vertebrae by 35%.
- The use of raloxifene increased the risk of developing fatal strokes and the risk of developing blood clots.
- The use of raloxifene did not affect the risk of CHD.
The researchers concluded that raloxifene significantly reduces the risk of developing breast cancer and fracture of the vertebrae among postmenopausal women with CHD or those at risk for developing CHD. However, its use is also associated with an increased risk of fatal strokes and blood clots. Postmenopausal women should speak with their physician regarding their individual risks and benefits of raloxifene.
Reference: Barrett-Connor E, Mosca L, Collins P, et al. Effects of Raloxifene on Cardiovascular Events and Breast Cancer in Postmenopausal Women. New England
Journal of Medicine. 2006; 355: 125-137.