Prevalence of Tamoxifen Use for Breast Cancer Chemoprevention Among US Women

Background: Tamoxifen can reduce the risk of developing invasive estrogen receptor-positive breast cancer by 49%, but it is unknown how many women in the United States are taking tamoxifen for primary prevention of breast cancer. Methods: Data from the years 2000 and 2005 National Health Interview Surveys were analyzed to estimate the prevalence of tamoxifen use among U.S. women for primary chemoprevention of breast cancer. Results: In 2000, similar to 0.2% of U.S. women ages 40 to 79 years without a personal history of breast cancer took tamoxifen for chemoprevention (95% confidence interval, 0.13-0.31). In 2005, the prevalence was similar to 0.08% (95% confidence interval, 0.03-0.17). Conclusion: The prevalence of tamoxifen use for primary prevention of breast cancer was very low in the years 2000 and 2005. Possible explanations for the low uptake are explored. Cancer Epidemiol Biomarkers Prev; 19(2); 443-6. (c) 2010 AACR.