Preventing Breast Cancer with Medical Treatment

Drug therapy clinical trials for preventing breast cancer in high risk women are called chemoprevention trials. In a five year chemoprevention study of 19,700 women with ADH or other factors that made them at a high risk for invasive breast cancer, the use of either tamoxifen or raloxifene, drugs that block or interfere with the actions of estrogen receptors, reduced the incidence of breast cancer about 50%. Side effects were higher with tamoxifen compared to raloxifene. A separate study of raloxifene vs. placebo showed a 72% reduction in cancer incidence at 4 years and a 66% reduction at 8 years.

Other classes of drugs, including inhibitors of aromatase, an enzyme involved in making estrogen, are being tested or considered for testing in breast cancer chemoprevention trials. In a study of NAF specimens in 33 women at the start and 6 months after taking either tamoxifen or raloxifene, NAF cytology was unchanged in 85% and improved in 11% while the biomarker PSA, which has been shown to be controlled by sex hormones and inversely associated with breast cancer, increased from 37 ng/L to 112 ng/L due to treatment.

US patent 7,128,877, licensed exclusively to Atossa, covers testing NAF for the biomarker PSA. Increased use of pharmaceutical treatments with chemopreventive agents in high risk women will lead to more NAF cytology studies to both diagnosis ADH and follow the effects of treatment.