The study is descriptive and aims to characterize the treatment patterns of advanced breast cancer in Poland in the real-world data setting. The main goals are to assess the current treatment patterns of hormone receptor-positive (HR+) Human epidermal growth factor receptor 2 negative (HER2-) advanced breast cancer and their changes in clinical practice and relate them to patients' demographics, disease characteristics, type of other therapies used in patients as well as disease progression and visceral crisis occurrence.

Inclusion Criteria:

• Adult patients with histologically diagnosed advanced breast cancer (with locoregional recurrence not eligible for radical local treatment or with distant metastases)
• Patient has a documented hormone (estrogen and/or progesterone) receptor expression and lack of HER2 receptor overexpression or lack of HER2 gene amplification (HR+/HER2- breast cancer subtype)
• Patient had no prior treatment for advanced breast cancer
• Patient has no symptomatic metastases to the central nervous system
• There is no other malignancies in patient requiring active treatment
• Patient is without co-occurring other malignancies treated with palliative assumption

Exclusion Criteria:

• Parallel patient's participation in any other clinical trial at the time when the decision over the advanced breast cancer treatment was made or up to 30 days before it.

Adult patients treated for the locally advanced/metastatic breast cancer of the HR+ HER2- subtype

Pfizer will provide access to individual de-identified participant data and related study documents (e.g. protocol, Statistical Analysis Plan (SAP), Clinical Study Report (CSR)) upon request from qualified researchers, and subject to certain criteria, conditions, and exceptions. Further details on Pfizer's data sharing criteria and process for requesting access can be found at: https://www.pfizer.com/science/clinical\_trials/trial\_data\_and\_results/data\_requests.