This session has two primary objectives: (1) to provide a review of recent research findings relating both endogenous and exogenous hormone exposures to later risk of breast cancer in women, and (2) to put these findings into context with what we already knew. For example, circulating levels of anti-Mullerian hormone (AMH), a hormone measureable only in premenopausal women, has recently been associated with increased risk of both premenopausal and postmenopausal breast cancer in a large prospective pooled analysis. Thus, circulating levels of AMH can now be considered along with the plasma estrogens and androgens (where weaker but consistent associations are observed) to be a probable or confirmed breast cancer risk factor. In postmenopausal women, plasma concentrations of sex steroid hormones, factors consistently linked with increased risk of breast cancer, were shown in recent studies to significantly improve breast cancer risk prediction models (such as the Gail Model). From older epidemiologic studies, we knew that recent or current use of oral contraceptives modestly increases risk of breast cancer, and this increase in risk subsides with duration since quitting use. Recent studies of newer contraceptives now add additional insight into this important issue.

Citation Format: Hankinson S. New data on hormones and risk of breast cancer [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr ES8-2.