The FDA recently approved Pfizer's Aromasin to treat postmenopausal women with estrogen-receptor-positive early breast cancer as a part of the 5-year treatment begun with tamoxifen. The FDA based its decision on results of the Intergroup Exemestane Study (IES), in which patients who switched to Aromasin after 2 to 3 years of tamoxifen therapy, for a total of 5 years, demonstrated a 31% greater protection from cancer recurrence than those who remained on tamoxifen for the entire 5-year period. This study was published in the New England Journal of Medicine, and, soon after, the American Society of Clinical Oncologists and the National Comprehensive Cancer Network revised their treatment guidelines to promote the use of Aromasin. The IES study included more than 4700 postmenopausal women with estrogen-receptor-positive breast cancer who were followed for an average of 35 months. Those patients receiving Aromasin had a significantly reduced occurrence of the cancer, compared with those receiving tamoxifen alonethis reduced recurrence included fewer local and distance tumors as well as new tumors in the other breast. Common side effects of Aromasin are mild-to-moderate hot flashes, fatigue, and arthralgia/bone pain. Aromasin should not be used in premenopausal women.
Ms. Farley is a freelance medical writer based in Wakefield, RI.