Study: Antihormone Drug Anastrozole May Prevent Breast Cancer in Postmenopausal Women
Women 53% less likely to develop disease over 5 years (December 12)
According to a study presented at the 2013 San Antonio Breast Cancer Symposium, held Dec. 10–14, the incidence of breast cancer among high-risk postmenopausal women was significantly reduced by the antihormone therapy anastrozole (Arimidex, AstraZeneca), indicating that the drug may be an effective new option for breast cancer prevention in this group of patients. The new data were simultaneously published in The Lancet.
A total of 3,864 postmenopausal women at increased risk for developing breast cancer were enrolled in the International Breast Cancer Intervention Study II (IBIS-II), conducted in the U.K. from 2003 to 2012. The women were considered to be at high risk for breast cancer if they fulfilled any one of a number of criteria, including having two or more blood relatives with breast cancer, having a mother or sister who had breast cancer before the age of 50, and having a mother or sister who had breast cancer in both breasts. Among the participants, 1,920 were randomly assigned to treatment with anastrozole for 5 years and 1,944 received placebo.
After a median follow-up period of slightly more than 5 years, the researchers found that women treated with anastrozole were 53% less likely to have developed breast cancer compared with women who received placebo. In addition, adverse effects consisted mostly of small increases in muscle aches and pains and in hot flashes, according to lead investigator Jack Cuzick, PhD.
“We are planning to continue following the IBIS-II Prevention participants for at least 10 years and, hopefully, much longer,” Cuzick said. “We want to determine whether anastrozole has a continued impact on cancer incidence even after stopping treatment and whether it reduces deaths from breast cancer, and to ensure that there are no long-term adverse side effects.”
Source: AACR; December 12, 2013.