ESR1 and ductal breast carcinoma in situ: A total of 14 variables were included in our multivariable Cox survival model: tumor histology (IDC vs. IDC + DCIS), age, race/ethnicity, Charlson-Deyo score, clinical T and N stage, ER status, PR status, Her2 status, surgery type, radiation therapy receipt, chemotherapy receipt, hormone therapy receipt, and tumor grade.