Patient-Centric Study to Assess the Impact of Genomic Profiling on the Treatment of Patients With Metastatic Breast Cancer in Spain

Inclusion Criteria: 1. Female or male patients residing in Spain. 2. Age ≥ 18 years. 3. Signed informed consent prior to any study-related procedures, except for registration. 4. Self-reported Eastern Cooperative Oncology Group (ECOG) performance status of 0-1. 5. Patients with metastatic breast cancer in at least one of these situations: 1. Patients recently diagnosed with ER+/HER2- metastatic breast cancer as a recurrence during adjuvant treatment and prior to initiating any treatment in the metastatic setting. 2. Patients with metastatic breast cancer of any subtype that have progressed after at least one line of treatment in the metastatic setting. Exclusion Criteria: 1. Presence of a condition or abnormality that, in the opinion of the investigators, would compromise the safety of the patient or the quality of the data. 2. Inability or refusal to commit with the procedures of the study at the moment of inclusion. 3. More than 3 prior systemic chemotherapy or antibody-drug conjugate (ADC) regimens for metastatic disease. Note: treatments for bone metastases (eg, bisphosphonates, denosumab, etc.), targeted therapies (eg, PARP inhibitors, CDK 4/6 inhibitors, immunotherapy etc.) and hormonal therapy are not considered as prior systemic chemotherapy treatments for advanced disease.