(HealthDay News) — Anastrozole reduces the risk of breast cancer by about half with few side effects in postmenopausal women at high risk of developing breast cancer, according to a study presented at the annual San Antonio Breast Cancer Symposium, held from Dec. 10 to 14 in San Antonio. The research was simultaneously published online Dec. 12 in The Lancet.
Jack Cuzick, Ph.D., from Queen Mary University in London, and colleagues randomly assigned 3,864 postmenopausal women (median age, 59.3 years; 47 percent had used hormone therapy) at high risk of developing breast cancer (such as having two or more blood relatives with breast cancer or having a mother or sister who developed breast cancer before 50 years of age) to placebo or anastrozole (1 mg/day).
After a median follow-up of 5.04 years, the researchers identified 125 breast cancers and 35 deaths. There were 25 ductal carcinomas in situ, 62 invasive estrogen receptor-positive cancers, 25 invasive estrogen receptor-negative cancers, and no details for 13 breast cancers. They found that women in the anastrozole group were 53 percent less likely to develop breast cancer. There were few side effects, largely muscle aches and pains and hot flashes.
“Our initial results show that for postmenopausal women who do not have breast cancer, but are at high risk for developing the disease, anastrozole reduced breast cancer incidence by 53 percent with very few side effects,” Cuzick said in a statement.
The study was partly funded by AstraZeneca and Sanofi-Aventis. Cuzick is on the speaker’s bureau for AstraZeneca.