Hormone replacement therapy and breast cancer

The use of hormone replacement therapy by postmenopausal women with a history of breast cancer is a subject of considerable controversy. There are no scientific studies that have appropriately examined the issue, and current practice is often based on inferences from indirect evidence, anecdotal experience, and personal bias. Our understanding of the effects of exogenous, as well as endogenous, hormones on normal and neoplastic breast tissue provides some insights but is not an appropriate basis for clinical practice. The effects of exogenous hormone replacement on the overall health of postmenopausal women, including psychosocial issues, cardiovascular risks, and the morbidity of osteoporosis, must be understood before patients can be counseled appropriately. Treatment of patients must be individualized. The rapidly expanding area of nonhormonal therapies for the treatment of postmenopausal health risks and the treatment of symptomatic complaints in postmenopausal women has already led to a reevaluation of the use of exogenous hormones among all women. A prospective randomized trial that examines the effects of hormone replacement on women with a history of breast cancer is currently underway and will provide valuable data to address these issues. The aim of this review is to outline the scientific basis for the association between estrogen and breast cancer and to provide a framework in which individualized recommendations concerning the use of hormone replacement therapy can be made for patients with breast cancer.