The prevalence of breast cancer (a hormonally driven neoplasm) in the United States, the potential health benefits of estrogen replacement therapy for postmenopausal women, and the burgeoning research focusing on selective estrogen receptor modulators (SERMs) have resulted in additional complexity in managing breast cancer. In an attempt to clarify existing data, the Society of Surgical Oncology sponsored a symposium entitled "Estrogens and Antiestrogens in Managing the Patient with Breast Cancer" at its 52nd Annual Cancer Symposium. This conference was held in March 1999 and was chaired by Dr. S. Eva Singletary, Professor of Surgery and Chief of the Surgical Breast Section at The University of Texas M. D. Anderson Cancer Center in Houston, Texas. The following is a review of the material presented by the symposium participants.