The main purpose of this study is to evaluate the effectiveness of inavolisib based regimen in participants with endocrine-resistant, phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha gene (PIK3CA)-mutated, hormone receptor-positive (HR+), human epidermal growth factor receptor 2-negative (HER2-) locally advanced or metastatic breast cancer (LA/mBC), following on or after completing adjuvant endocrine therapy in routine clinical practice in China.
Participants must be diagnosed with endocrine-resistant, PIK3CA-mutated, HR+/HER2- LA/mBC, following recurrence on or after completing adjuvant endocrine therapy
Participants must receive the treatment of inavolisib for the first time
PIK3CA mutation status should be detected by a National Medical Products Administration (NMPA)-approved or validated assay [Polymerase Chain Reaction (PCR) or Next Generation Sequencing (NGS)] by testing of blood or tumor tissue prior to the initiation of inavolisib
Participants for which the treatment with inavolisib is not indicated per prescribing information. If the participant starts palbociclib and fulvestrant first, and starts inavolisib after getting a PIK3CA mutation-positive test result later, the palbociclib and fulvestrant will not be deemed as a different line of therapy. However, the medical order of PIK3CA mutation test must be made before or at the same time with the prescription of palbociclib and fulvestrant
Participants not receiving treatment for LA/mBC with inavolisib according to standard of care (SOC) and in line with the current summary of product characteristics (SPC)/local labeling
At the investigator's discretion, any reason that makes the participant hard to follow up or unsuitable to participate in the study