It is now possible to prevent many breast cancers inhigh-risk women using anti-estrogen hormonal drugs. Several Phase III breast cancer preventiontrials demonstrated that hormonal drugs such as the “selective estrogenreceptor modulators” tamoxifen and raloxifene, and aromatase inhibitors preventthe development of 50% of ER-positive breast cancers in women. However, mostwomen at high risk of breast cancer do not use these cancer preventive drugsdue to concerns about their side effects. To overcome this problem, recent studies havefocused on testing novel approaches for the prevention of breast cancer. Results of preclinical and clinical studiestesting targeted drugs and vaccines for breast cancer prevention show that itis possible to prevent breast cancer with reduced toxicity. Studies seeking to prevent all forms ofbreast cancer, including ER-positive, HER2-positive, and “triple-negative”breast cancer, will be presented and discussed. Novel approaches testing targeted therapies including signalinginhibitors, combinations of preventive agents, and vaccines, will be presented. Many of these interventions prevent breastcancer in animal models, and are now being tested in human clinicaltrials. Results from studies testing novel drugdelivery approaches will also be discussed. Topical gels containing anti-estrogen drugs are being used to reducebreast cell growth and mammographic density in Phase II clinical trials. This topical approach has the potential toprevent ER-positive breast cancers without the toxicity of oral hormonaldrugs. All of these novel preventive measuresoffer great promise to effectively prevent all forms of breast cancer withminimal toxicity.

Citation Format: P Brown. Beyond Hormones: Newer Pharmacologic Approaches [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr SP020.