Clinical Research Directory

Inclusion Criteria: 1. Age ≥ 18 years old; 2. Patients diagnosed with HR+/HER2- (as defined by the ASCO/CAP guidelines) advanced breast cancer who were treated in our hospital from March 2022 to March 2025; 3. Received CDK4/6 inhibitors (including but not limited to the four currently marketed ones: palbociclib, abemaciclib, ribociclib, and dalpiciclib) as advanced-stage treatment for at least one cycle; 4. Have complete medical history records, including demographic information, pathological reports, treatment records, laboratory test results, and imaging examination reports, etc. Exclusion Criteria: 1. Incomplete medical history data. 2. Only received CDK4/6 inhibitors monotherapy. 3. Received CDK4/6 inhibitors as neoadjuvant/postoperative adjuvant intensification therapy.