The Ibandronate with or without Capecitabine in Elderly Patients with Early Breast Cancer—(ICE Study), prospectively studied 1358 patients aged ≥65 years, with node-positive or high-risk (at least one of the following: tumor size ≥2 cm, Grade 2–3, ER and PR negative) node-negative early-stage breast cancer who were deemed inappropriate for conventional treatment. Here, ESR1 is linked to breast cancer.