Eliminating (or at least significantly reducing) the chances that a person gets breast cancer is the ultimate goal of breast cancer research. In addition to adopting a healthier lifestyle, women at high risk for developing breast cancer have the option of taking breast cancer prevention drugs. Currently, there are only two drugs, tamoxifen and raloxifene , that have been approved for the prevention of breast cancer. However, neither of these breast cancer prevention drugs are well-accepted by women at high risk for breast cancer due to their undesireable side effects. Therefore, there remains a push for the development of better breast cancer prevention drugs. The most promising breast cancer prevention to date might be exemestane , an aromatase inhibitor.
The results of a large clinical trial on the benefits of exemestane for breast cancer prevention were recently published ( free to download ) in the New England Journal of Medicine and suggest that this aromatase inhibitor might be a better option than tamoxifen or raloxifene for breast cancer prevention.
In this new breast cancer study, 4,560 postmenopausal women from around the world who were at an elevated risk for breast cancer were randomly assigned to receive a placebo pill or a pill containing 25 milligrams of exemestane. Development of breast cancer and rates of side effects were measured during a 3-year follow-up period. The study investigators reported...
Exemestane reduced the incidence of invasive breast cancer by 65% compared to the control group.
Incidence of invasive plus non-invasive breast cancers was reduced by 53% in the exemestane group compared to the placebo group.
The risk for developing lesions that might later develop into breast cancer (lobular carcinoma in situ, atypical ductal hyperplasia, and atypical lobular hyperplasia) was reduced by 64%
Serious side effects like cardiovascular events, fractures, and abnormal liver function were not increased by exemestane use compared to the placebo group.
Exemestane use did result in more common occurrences of arthritis and menopausal symptoms.
Overall, this is a very positive study for exemestane in regards to its effectiveness for breast cancer prevention and in regards to its safety profile. Not only did exemestane use reduce the risk of developing breast cancer, but it reduced the risk of developing breast lesions that put women at greater risk for developing breast cancer in the future. The safety profile described in this paper suggests that exemestane might be a better option for some women than either tamoxifen or raloxifene. Nonetheless, longer studies will probably need to be done before exemestane can be approved for breast cancer prevention use and even then it remains uncertain if it will be accepted any better than the two currently approved breast cancer drugs.