In NEJM this week, researchers from the US, Europe, and Canada present findings from a study of exemestane for the prevention of breast cancer in post-menopausal women. In a randomized, placebo-controlled, double-blind trial of 4,560 women with a median age of 62.5 years, 11 invasive breast cancers were detected in the group randomly assigned to take exemestane, compared to 32 cancers detected in the placebo group, at a median follow-up of 35 months. Adverse events occurred in 88 percent of the exemestane group and 85 percent of the placebo group, the authors write, and there were no significant differences between the two groups in terms of skeletal fractures, cardiovascular events, or other cancers. "Exemestane significantly reduced invasive breast cancers in postmenopausal women who were at moderately increased risk for breast cancer," the researchers add.
Also in NEJM this week, the University of Pittsburgh Cancer Institute's Nancy Davidson and Thomas Kensler map the course of chemoprevention in breast cancer since the introduction of tamoxifen. A 1992 NEJM editorial foreshadowed a role for tamoxifen in breast cancer chemoprevention, and nearly 20 years later, treatment of high-risk women with tamoxifen for five years can reduce the chance they will be diagnosed with breast cancer by about 50 percent, Davidson and Kensler write. Its sister drug, raloxifene, is almost as effective. During this time, researchers also discovered aromatase inhibitors, which reduced breast cancer recurrence even more than tamoxifen in clinical trials. Now, researchers are studying compounds like exemestane, Davidson and Kensler say, which can lead to a 65 percent reduction in the diagnosis of an invasive breast cancer. "Breast cancer is the second most common cause of death from cancer and one of the most feared diagnoses for women in the United States. We have the knowledge and tools to reduce its incidence today," they add.