HR+/ HER2- Advanced/ Metastatic Breast Cancer Real World Treatment Patterns and Outcomes
HR+/ HER2- Advanced/ Metastatic Breast Cancer Real World Treatment Patterns and Outcomes
This is a retrospective, observational study that will document the treatment patterns and
 clinical outcomes of patients diagnosed with HR+/HER2- A/MBC who received CDK4/6i combination
 therapy with aromatase inhibitors (AI) as the initial endocrine-based therapy in the A/MBC
 setting.
Inclusion Criteria:

 1. Female or male sex.

 2. Diagnosis (confirmed by clinical review) of A/MBC, defined as breast cancer at stage
 IIIB, stage IIIC, stage IV or identified as having distant metastasis.

 3. Age ≥18 years at A/MBC diagnosis.

 4. Initiated a CDK4/6i in combination with an AI as initial endocrine-based therapy after
 A/MBC diagnosis on or after 2/3/2015 and before 4/1/2019.

 •Note that the date of the start of the inclusion period reflects the month that the
 first CDK4/6i (ie, Palbociclib) received U.S. FDA approval.

 5. Evidence of ER or PR positive disease, or absence of any indication of ER and PR
 negative disease closest to A/MBC diagnosis (ie, patients are eligible without
 affirmative indication of ER/PR+ status as long as ER/PR- indication is not present).

 6. Evidence of HER2 negative disease, or absence of any indication of HER2 positive
 disease closest to A/MBC diagnosis (ie, patients are eligible without affirmative
 indication of HER2- status as long as HER2+ indication is not present).

 Exclusion Criteria:

 1. Enrollment in an interventional clinical trial for A/MBC during the study observation
 period.