The purpose of this study is to compare the safety and efficacy of epirubicin plus cyclophosphamide versus docetaxel plus cyclophosphamide in lymph node negative, estrogen receptor (ER) positive, human epithelial growth factor receptor 2 (HER2) negative breast cancer patients as adjuvant chemotherapy.

This is a non-inferiority study. According to previous study results, the investigators hypothesize the incidence of grade 3-4 neutropenia is 40%, with a α of 0.05 and β of 0.8, a sample size of 264 cases if needed.

Inclusion Criteria:

1. Women aged ≥18 years and < 70 years with life expectancy > 12 months
2. Have finished radical operation, pathologically verified no lymph node involvement
3. Operation specimens are available for ER, progesterone receptor (PR) and Her2 detection, patients should be with ER positive, Her2 negative tumor.
4. Adequate bone marrow function
5. Adequate liver and renal function
6. Has Eastern Cooperative Oncology Group (ECOG0 Performance Score 0-1;
7. Women with potential child-bearing must have a negative pregnancy test (urine or serum) within 7 days of drug administration and agree to use an acceptable method of birth control to avoid pregnancy for the duration of the study;
8. Written informed consent according to the local ethics committee requirements.

Exclusion Criteria:

1. Prior systemic or loco-regional treatment of breast cancer, including chemotherapy;
2. Metastatic breast cancer;
3. With a history of malignant tumor except uterine cervix cancer in situ or skin basal cell carcinoma;
4. Patients with medical conditions that indicate intolerant to adjuvant chemotherapy and related treatment, including uncontrolled pulmonary disease, diabetes mellitus, severe infection, active peptic ulcer, coagulation disorder, connective tissue disease or myelo-suppressive disease;
5. Has active hepatitis B or hepatitis C with abnormal liver function tests (LFTs) or is known to be HIV positive;
6. History of congestive heart failure, uncontrolled or symptomatic angina pectoris, arrhythmia or myocardial infarction; poorly controlled hypertension;
7. Has peripheral neuropathy ≥ grade 1;
8. Patient is pregnant or breast feeding;
9. Known severe hypersensitivity to any drugs in this study;
10. Treatment with any investigational drugs within 30 days before the beginning of study treatment.

There is no plan to share IPD