This is a prospective, randomised, multicenter, no placebo-controlled, open label study for evaluating the efficacy and safety of pyrotinib in women with residual invasive HER2-positive breast cancer after neoadjuvant chemotherapy plus anti-HER2 target therapy. The main purpose is to investigate whether pyrotinib can further reduce the risk of recurrence from previously diagnosed HER-2 positive breast cancer based on the 1-year trastuzumab standard adjuvant treatment with or without pertuzumab.

Inclusion Criteria:

• Female, Aged ≥18 and ≤70 years;
• Histologically confirmed invasive HER2 positive breast cancer, early disease(Stage ⅡA-Ⅲ) ;
• Completed neoadjuvant therapy, including chemotherapy and trastuzumab;
• Residual invasive disease was detected pathologically in the surgical specimen of the breast or axillary lymph nodes after completion of neoadjuvant chemotherapy;
• Been or being treated for early breast cancer with standard of care duration of trastuzumab;
• Adjuvant treatment regimen needs to be determined before randomization;
• Duration from Random time to the last use of trastuzumab≤1 year.
• Performance Status- Eastern Cooperative Oncology Group (ECOG) 0-1;
• Required laboratory values including following parameters:ANC: ≥ 1.5 x 109/L; Platelet count: ≥ 100 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: ≥ 50%; QTcF: < 470 ms
• Signed informed consent form (ICF) .

Exclusion Criteria:

• Metastatic disease (Stage IV) ;
• Gross residual disease remaining after mastectomy or positive margins after breast-conserving surgery;
• Progressive disease during neoadjuvant therapy;
• Subjects that are unable to swallow tablets, or dysfunction of gastrointestinal absorption;
• Treated or treating with anti-HER2 TKI, including but not limited to pyrotinib, lapatinib and neratinib.
• Less than 4 weeks from the last clinical trial;
• History of immunodeficiency, including HIV-positive, suffering from other acquired, congenital immunodeficiency disease, or history of organ transplantation;
• Subjects had any heart disease, including: (1) angina; (2) requiring medication or clinically significant arrhythmia; (3) myocardial infarction; (4) heart failure; (5) Any heart diseases judged by investigator as unsuitable to participate in the trial;
• Female patients who are pregnancy, lactation or women who are of childbearing potential tested positive in baseline pregnancy test;Female patients of childbearing age that are reluctant to take effective contraceptive measures throughout the trial period;
• Evidence of significant medical illness that in the investigator's judgment will substantially increase the risk associated with the subject's participation in and completion of the study.