Study Of Real-World Evidence In Patients Treated With Palbociclib During a 2.5 Years Follow-Up Period

PALBO is a Non-Interventional, National Study Of Real-World Evidence In Estrogen Receptor Positive, Her2 Negative Metastatic Breast Cancer Patients Treated With Palbociclib During A 2.5 Years Follow-Up Period. The primary objective is to identify pathological and clinical features of MBC that is associated with Palbociclib's best efficacy, measured by response rate (overall response rate, duration of response and best clinical response), progression free survival and OS. Safety of Palbociclib will also be evaluated.