Cardiac Outcomes With Near-Complete Estrogen Deprivation

Inclusion Criteria * Women age ≤55 who were premenopausal at the time of breast cancer diagnosis; (Premenopausal is defined as per NCCN criteria). * Planned breast cancer treatment with NCED (near-complete estrogen deprivation) therapy that includes aromatase inhibitor therapy (or SERD) with medically or surgically induced menopause within three (3) months of initiating NCED (HR-positive tumor) or, for the cohorts not receiving NCED therapy, within three (3) months of planned chemotherapy, surgery or radiation. Index date for three months is defined as final date of treatment with chemotherapy, surgery or radiation which ever happens last (HR-negative tumor). Treatment with a Gonadotropin Releasing Hormone (GnRH) agonist for fertility preservation during chemotherapy is allowed and is not considered part of the NCED antineoplastic therapy. * Women with human epidermal growth factor-2 (HER2) negative and women with human epidermal growth factor-2 (HER2) positive breast cancer are eligible. * Treatment with CDK-inhibitor, PARP inhibitor immunotherapy or biologic (non-chemotherapy) agent as part of anti-neoplastic treatment plan is allowed. These agents are not considered chemotherapy. * Treatment with selective-estrogen receptor degrader (SERD) rather than aromatase inhibitor is allowed. * Diagnosed with Stage I-III breast cancer. * ECOG performance status of 0-2 * Patients with concurrent malignancies are eligible as long as therapies and disease course for these are reasonab…