ESR1 and breast cancer: In this study, we adapted an established CISNET breast cancer simulation model, developed at Georgetown University and Albert Einstein College of Medicine (Model G-E), to synthesize high-quality nationally representative data and simulate lifetime risks of contralateral breast cancer, primary breast cancer, and other-cause survival in U.S. women diagnosed with ER+/HER2- breast cancer by age group, endocrine therapy regimen and duration22,23.