The investigators plan to carry out a phase II, open-label, single-arm clinical study of short-course trastuzumab, pertuzumab combined with taxanes in the adjuvant treatment of early HER2-positive breast cancer, to explore whether 4 courses of dual HER2 blockade combined with taxanes can lead to a similar prognosis with current standard treatment, which is one-year trastuzumab monotherapy combined with chemotherapy, while reducing the adverse reactions of treatment.

Inclusion Criteria:

• Histologically diagnosed unilateral primary invasive breast cancer patient with pT1, pN0, and M0 disease
• HER2-positive, ie. immunohistochemistry [IHC] 3+ or IHC 2+ and fluorescence in situ hybridisation [FISH]-positive according to ASCO/CAP 2018 guidelines
• complete clinical pathological information
• Eastern Cooperative oncology Group [ECOG] 0-1
• Currently not pregnant or breast-feeding
• Fine organ function
• Have good compliance with planned treatment, understand the study process and sign a written informed consent

Exclusion Criteria:

• Bilateral or metastatic breast cancer
• Receiving neoadjuvant treatment
• Other malignancies within 5 years, except for cured cervical carcinoma in situ and non-melanoma skin cancer
• Severe systemic infections or other serious illnesses
• HIV infection, active hepatitis B or C infection
• Known allergy to or intolerance to a therapeutic drug or its excipients
• Prior history of chemotherapy, endocrine therapy, biotherapy, or radiation therapy for any reason
• Enrollment of another investigational study within 4 weeks prior to initial administration of the investigational treatment
• Receiving live vaccine within 30 days prior to initial administration of the investigational treatment
• History of mental illness or drug abuse that may affect compliance with the trial requirements
• The researchers determine that the patients were not suitable for the study