Study to Compare Overall Survival in Medicare Patients With Metastatic Breast Cancer Treated With a Medicine Called Palbociclib in Combination With Aromatase Inhibitor and Aromatase Inhibitor by Itself.
Status: ACTIVE_NOT_RECRUITING
Study type: OBSERVATIONAL
Conditions: Breast Cancer
Interventions: DRUG: Palbociclib|DRUG: Aromatase Inhibitor
Sponsor: Pfizer