Patient description: The patient is a 42 year-old postmenopausal woman who had a screening sonogram which revealed an abnormality in the right breast. She had no palpable masses on breast exam. Core biopsy was done and revealed a 1.8 cm infiltrating ductal breast carcinoma in the left upper outer quadrant. Lumpectomy was done and the surgical margins were clear. The tumor was HER2-positive and ER/PR negative. Axillary sampling revealed 1 positive lymph node out of 12 sampled. CXR was unremarkable. She is using “well women” multivitamins daily and no other medication. She smokes frequently and consumes alcohol occasionally. She is in a relation with only one partner and has a history of 3 pregnancies and live births. She breastfed all three children.

Clinical trial eligibility criteria: eligible ages (years): 18.0-80.0,  HER2-positive Breast Cancer the first diagnosis of invasive breast cancer, confirmed by histology or cytology, and surgical resection of the primary lesions before receiving any anti breast cancer treatment; 2. female patients, aged 18 years and less than 80 years of age; 3. surgical resection of the primary tumor pathological examination, showed HER2 positive (defined as immunohistochemistry [IHC] 3+ or fluorescence in situ hybridization (FISH) positive); 4. hormone receptor status is known, lymph node positive or sentinel lymph node negative but high risk factors 5. the eastern oncology cooperative group (ECOG) patients with physical status score was 0 -2; 6. baseline LVEF >50% 7. the relevant institutional review board (IRB) or independent ethics committee (IEC) written informed consent  the subjects in pregnancy or lactation; 2. pregnant women may be within the first 7 days before pregnancy test positive (urine or serum). 3. received chemotherapy, endocrine or anti HER2 anti-tumor therapy; 4. congestive heart failure, unstable angina, heart failure or myocardial infarction and other diseases; 5. other invasive tumors (including the second primary breast cancer), may affect the outcome of the evaluation and program compliance; but the treatment of patients with disease free survival at least more than 5 years can be selected; 6. with chronic liver disease in patients with liver dysfunction and / or with clinical manifestations: the serum total bilirubin > 2.5 * ULN; or INR = 1.5 but no bilirubin. serum ALT or AST> * 3 * ULN; alkaline phosphatase >2.5 * ULN; ALT or AST can be gradually increased, but with gradually increasing fatigue, nausea and vomiting, fever, right upper quadrant pain or tenderness 7. hematopoietic dysfunction, defined as follows: neutrophil count (ANC) <1.5 * 109/L; platelet <100 * 109/L; hemoglobin <9 g/dL; 8. other serious diseases, including: congestive heart failure (heart function NYHA grade II, III, IV) or occurred within 6 months of congestive heart failure, unstable angina, arrhythmia, myocardial infarction patients can't control or other severe cardiovascular disease; breathing at rest or need oxygen therapy; serious infection; uncontrolled diabetes; 9. there is a serious psychological or mental abnormalities, estimated that the participants to participate in this study is not strong; 10. known to study drug allergy; 11. the past 30 days participated in the study of other drug clinical trials. 1, failed to complete the clinical trial of at least 1 cycles according to the program, can not carry out safety and efficacy evaluation 2, a serious violation of this research program, not in accordance with the prescribed dose, method and course of medication. Patients will receive lapatinib treatment, until a predetermined end end point, or development of unacceptable toxicity, or withdrawal of consent, or illness or death, to appear before the subject