Adjuvant Ovarian Suppression Plus Aromatase Inhibitor or Tamoxifen in Young Women

Inclusion Criteria:

1. Signed informed consent;
2. Eastern Cooperative Oncology Group (ECOG) performance status ≤ 2;
3. Patients pathologically diagnosed with hormone receptor positive invasive breastcancer: immunohistochemistry ER positive (≥1%);
4. Premenopausal patients with age ≤35 years (at least menstruate once for prior 3months, assess menstruation situation before chemotherapy if have);
5. No distant metastasis;
6. Clinical stage (TNM) meets at least one of the conditions as follow: T≥2cm or at leastone region of regional lymph node metastasis (including micrometastases);
7. Patients must have undergone a surgery and (neo)adjuvant chemotherapy, targetedtherapy, radiotherapy (if necessary) according to Chinese Anti-Cancer Associationguidelines and specifications version 2015 for diagnosis and treatment of breastcancer;
8. Indexes of hematology and biochemistry conform to following standards: HGB≥10g/dl,WBC≥4,000/mm3, PLT≥100,000/mm3, GOT, GPT, ALP≤2xULN, TBIL, DBIL, CCr≤1.5xULN.

Exclusion Criteria:

1. Pregnant or lactating women or women of childbearing potential reject contraceptivemeasures;
2. History of organ transplantation (including autologous bone marrow transplantation andperipheral stem cell transplantation);
3. Concurrent malignancies or history of non-breast malignancies within the 5 years priorto study entry, except for curatively treated basal cell and squamous cell carcinomasof the skin, carcinoma in situ of the cervix; peripheral nervous system disorderscaused by diseases or history of obvious mental and central nervous system disorders;
4. Prior use of neo-adjuvant chemotherapy after a definite diagnosis;
5. Nervous system disorders caused by diseases or obvious mental disorder, which wouldaffect patients right to consent and compliance, or make patients in criticalcondition;
6. Serious hepatopathy (e.g., cirrhosis, etc.), nephropathy, respiratory illness,digestive illness or poorly controlled diabetes;
7. Cardiac illness with obvious abnormal EKG or clinical symptoms, namely congestiveheart failure, coronary atherosclerotic heart disease with obvious symptoms,arrhythmia difficult to control by drugs, or history of myocardial infarction withinthe 12 months prior to study entry or class III/IV of cardiac function;
8. Concurrent treatment in another investigational trial;
9. Sensitivity or contraindication to any of the study medications.