Tamoxifen for the prevention of breast cancer in the high-risk woman.

Abstract

In 1998, a major landmark in the battle against breast cancer was reached when the National Surgical Adjuvant Breast and Bowel Project (NSABP) P-1 prevention trial1 demonstrated a 49% reduction in the risk of invasive breast carcinoma in high-risk women who took tamoxifen for 5 years. The significance of this result was questioned when two additional reports from the Royal Marsden2 and Italy3 demonstrated no reduction in rate of occurrence of breast cancer with tamoxifen. However, these should not be viewed as one positive and two negative trials, because the European studies were not completed prospective clinical trials designed to answer the chemoprevention question. Most important, the use of tamoxifen for prevention is the culmination of more than 30 years of laboratory research that has been translated into clinical practice, and a large data base of breast cancer patients treated with tamoxifen and followed for 10 years exists to address some of the questions suggested by the initial results of the prevention studies.