A joint guideline from the Canadian Task Force on Preventive Health Care and the Canadian Breast Cancer Initiative’s Steering Committee on Clinical Practice Guidelines for the Care and Treatment of Breast Cancer

Abstract

"Evidence from epidemiological and experimental animal studies suggests that both endogenous and exogenous estrogens play a significant role in breast cancer development. Many of the established risk factors relate to the timing of exposures and the cumulative exposure of breast tissue to these hormones.1–4 This suggests that a pharmacological approach to modulating risk could be effective."