RT Journal Article SR Electronic T1 The Breast Cancer Prevention Trial (P-1 Study) JF Cleveland Clinic Journal of Medicine JO Cleve Clin J Med FD Cleveland Clinic SP 33 OP 40 VO 66 IS 1 A1 Overmoyer, Beth A. YR 1999 UL http://www.ccjm.org/content/66/1/33.abstract AB The recently completed Breast Cancer Prevention Trial found that tamoxifen can reduce the incidence of breast cancer by nearly half in women at high risk, but the benefit comes at a price of increased risk of endometrial cancer and thromboembolism. This article reviews the actions of tamoxifen and the design, findings, and implications of this study.