This Study Aims to Optimize Neoadjuvant Therapy for HER2-positive Breast Cancer by Implementing a Dynamic Monitoring-guided Treatment Strategy.

Inclusion criteria

• ✓. Histologically confirmed invasive cancer of the breast and meet the clinical stage II（T2N0-1M0/T3N0M0）or III（T2N2M0/T3N1-2M0) criteria;
• ✓. Age between18-70 years;
• ✓. Eastern Cooperative Oncology Group (ECOG) performance status 0-1;
• ✓. Histologically confirmed to be HER2-positive invasive breast cancer;
• ✓. LVEF≥55%；
• ✓. At least one measurable lesion according to RECIST version 1.1
• ✓. Normal organ and marrow function: Hemoglobin (HB) ≥90 g/L (No blood was transfused within 14 days), Absolute neutrophil count ≥ 1500/μL, Platelets ≥ 75,000/μL, Total bilirubin ≤ 1.5 x ULN), aspartate aminotransferase (AST) (SGOT) and alanine aminotransferase (ALT) (SGPT) ≤ 3 x ULN, creatinine \< 1 x ULN, endogenous creatinine clearance \> 50 ml/min (Cockcroft-Gault formula);
• ✓. Non-pregnant and non-lactating, fertile female subjects were required to use a medically approved contraceptive method for the duration of the study treatment and at least 3 months after the last use of the study drug; Ability to understand and willingness to sign a written informed consent

Exclusion criteria