#B141 Tamoxifen Eligibility, Net Benefit and Use for Breast Cancer Chemoprevention among White Women in the U.S. Andrew Freedman, National Cancer Institute, Bethesda, MD. Background: Assessing the overall public health impact of the chemopreventive use of tamoxifen among women in the U.S. general population requires evaluating the number of women who are eligible to take the drug based on U.S. Food and Drug Administration (FDA) indications, the number for whom the adverse events of taking tamoxifen outweigh the proven benefits for breast cancer risk reduction, and the number actually taking the drug for breast cancer chemoprevention. Methods: Using weighted data from the 2000 National Health Interview Survey Cancer Control Module, we provide national estimates for the total number of white U.S. women without a previous diagnosis of breast cancer who would be eligible for tamoxifen chemoprevention based on FDA indications (women age 35 years and older who had a 5-year risk of breast cancer of 1.67% using the “Gail” Breast Cancer Risk Assessment Model). Estimates also were calculated for the total number of white U.S. women who would benefit from tamoxifen chemoprevention based on evidence for a positive benefit/risk index. The benefit/risk index takes into account tamoxifen’s adverse events, (e.g. excesses of endometrial cancer, pulmonary embolism, stroke, deep vein thrombosis, and cataracts) as well as its proven benefits for reducing breast cancer risk based on a woman’s age, race, risk factors for breast cancer, and whether or not she has a uterus. Estimates also were calculated for the total number of white U.S. women without a previous diagnosis of breast cancer who reported current use of the drug. Results: For all 50,104,829 white women ages 35 to 79 in the U.S. population in 2000, 9,377,715 or 18.7% (95% = CI 17.8% to 19.7%) were eligible for tamoxifen chemoprevention based on FDA indications, but only 2,431,911 or 4.9% (95% CI = 4.3% to 5.4%) had a positive benefit/risk index. The percentage of white women benefiting varied by age, with 0% benefiting at ages 35−39, 8.1% at ages 40−49, 8.5% at ages 50−59, 2.1% at ages 60−69, and 0.1% at ages 70−79. Only 70,761 or 0.2% (95% CI= 0.1% to 0.3%) of all white women without a previous diagnosis of breast cancer reported that they were currently using tamoxifen. Conclusions: Although a substantial percentage of U.S. women (18.7%) would be eligible for breast cancer chemoprevention with tamoxifen based on FDA indications, a much smaller percentage (4.9%) would have an estimated net benefit based on their age and breast cancer risk factors. Few white women without a previous diagnosis of breast cancer (0.2%) currently use tamoxifen. These data have implications for educating healthcare professionals in evaluating the eligibility, net benefit, and appropriate use of tamoxifen for breast cancer chemoprevention for women in the U.S. population. Frontiers in Cancer Prevention Research, 2003 AACR Abstract #B176 Frontiers in Cancer Prevention Res, 2003 Abstract #C158 Frontiers in Cancer Prevention Res, 2003 Remember we are NOT Doctors and have NO medical training. This site is like an Encylopedia - there are many pages, many links on many topics. Support our work with any size DONATION - see left side of any page - for how to donate. You can help raise awareness of CAM.