CDK4/6 Inhibitor Intensification and Chemotherapy De-Escalation for Early-stage Luminal-HER2 Breast Cancer

CDK 4/6 inhibitor and endocrine therapy combined with Trastuzumab ( without chemotherapy)

four cycles of docetaxel and cyclophosphamide or four cycles of weekly paclitaxel Combined with Trastuzumab followed by standard endocrine therapy( aromatase inhibitors or tamoxifen，Ovarian function suppression agents may be added if premenopausal)