Observational Study of Bone Complications in People With Post-menopausal Breast Cancer Who Have Stopped Treatment With Denosumab and Aromatase Inhibitors

Inclusion Criteria: * Women with Stage 0-3 breast cancer confirmed at MSKCC * Currently have no clinical evidence of disease * Participant must be post-menopausal, defined as last menstrual cycle at least 12 months prior to enrollment * Received at least 2 doses of denosumab and then discontinued therapy * Discontinued AI prior to or within 6 months of last denosumab injection * Patients must be 18 years of age or olde Exclusion Criteria: * Patients with history of osteoporosis prior to starting denosumab, based on previous dual-energy X-ray absorptiometry (DEXA) scan; * Patients with history of insufficiency fracture. * Patients who continue treatment with a different bone modifying agent (i.e oral or intravenous bisphosphonates) after discontinuation of denosumab * Patients on chronic low-dose glucosteroids.