Compare Continuation of Original Targeted Therapy With Trastuzumab Combined With Pyrotinib and Capecitabine as Postoperative Adjuvant Therapy in Non-pCR Patients With HER2 Positive Early Breast Cancer

Inclusion Criteria: * Female patients aged ≥ 18 years and ≤ 75 years old with primary breast cancer * ECOG score 0 \~ 1 * Breast cancer meets the following criteria: 1）Histologically or pathologically confirmed invasive breast cancer, primary tumor stage determined by standard evaluation methods：cT1-4/N0-3/M0. 2）Pathologically confirmed HER2-expressing positive breast cancer, defined as \> 10% immunoreactive cells with immunohistochemical (IHC) score of 3 + or in situ hybridization (ISH) results of HER2 gene amplification. 3)Known hormone receptor status (ER and PgR). 4)Neoadjuvant therapy (including: at least 9 weeks of trastuzumab treatment and at least 9 weeks of taxane chemotherapy) * Primary breast cancer lesion or lymph node invasive cancer confirmed by pathology after neoadjuvant therapy (residual invasive breast cancer lesion \> 2 cm or axillary lymph node positive with macrometastasis assessed by central laboratory) * No more than 12 weeks between end of surgery (without post-operative radiotherapy) and randomisation or 6 weeks between end of post-operative radiotherapy and randomisation * Required laboratory values including following parameters: ANC: ≥ 1.5 x 109/L Platelet count: ≥ 90 x 109/L Hemoglobin: ≥ 9.0 g/dL Total bilirubin: ≤ 1.5 x upper limit of normal, ULN ALT and AST: ≤ 1.5 x ULN BUN and creatine clearance rate: ≥ 50 mL/min LVEF: ≥ 55% QTcF: \< 470 ms Exclusion Criteria: * 1\) Stage IV (metastatic) breast cancer; * 2\) inflammatory breast cancer; * 3\) Previous anti-tumor therapy or radiotherapy for any malignancy, excluding cured cervical carcinoma in situ, basal cell carcinoma or squamous cell carcinoma; * 4\) Receiving anti-tumor therapy in other clinical trials, including bisphosphonate therapy or immunotherapy (except radiotherapy and endocrine therapy during treatment); * 5\) Receiving any anti-tumor therapy within 28 days before enrollment; * 6\) Peripheral neuropathy ≥ Grade 2 as specified by NCI CTCAE; * 7\) Receiving pyrrolidone or other anti-HER2 tyrosine kinase inhibitors; * 8\) Receiving anthracycline therapy with cumulative doses as follows: adriamycin \> 240 mg/m2, epirubicin \> 480 mg/m2; * 9\) Receiving major surgery unrelated to breast cancer before randomization, or the patient has not fully recovered from surgery