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

• Stage IV (metastatic) breast cancer.
• The patient has a second primary malignant tumor, except for fully treated skin cancer.
• The patient had undergone major surgical procedures unrelated to breast cancer within 4 weeks before enrollment, or the patient has not fully recovered from such surgical procedures.
• The presence of uncontrolled cardiovascular and cerebrovascular disease, including (but not limited to) any of the following within the 6 months prior to the first dose: congestive heart failure (NYHA III or IV), myocardial infarction or cerebral infarction, pulmonary embolism, unstable angina, or arrhythmia requiring treatment at the time of screening; 5.Primary cardiomyopathy (e.g., dilated cardiomyopathy, hypertrophic cardiomyopathy, arrhythmogenic right ventricular cardiomyopathy, restricted cardiomyopathy, undefined cardiomyopathy); A clinically significant history of prolonged QTc, grade II type II atrioventricular block or grade III atrioventricular block or QTc interphase (F method) > 470 msec (female); Atrial fibrillation (EHRA grade ≥2b); Unmanageable hypertension, which the investigators judged unsuitable for study participation.

6.Individuals with a known history of allergies to the drug components of this protocol; 7.Having a history of immunodeficiency, including HIV testing positive, or suffering from other acquired or congenital immunodeficiency diseases, or having a history of organ transplantation.