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): 20.0-999.0,  Breast Cancer Histologically proven primary invasive breast cancer which is thought to be suitable for neo-adjuvant treatment 2. Pathologically proven lymph node positive tumor(FNAB or Core biopsy) 3. Tumor must be ER positive(eligible patients Allred score 5 and more, Modified Allred 4 and more) and HER-2 negative(IHC score is 0-1+; If IHC score is 2+, the result of FISH or SISH is negative) 4. Premenopausal women Premenopausal status as defined by  Last menses within 6 month of randomization or For patients who have had a unilateral oophorectomy, E2 ≥ 20PG/mL and FSH < 30mIU/Ml within 4 weeks of randomization 5. over 20 years old 6. Pre-treatment haematology and biochemistry values within acceptable limits  ANC ≥ 1.5 × 109/l Hb > 9g/dl Platelets ≥ 100 × 109/l AST/ALT ≤ 1.5 × ULN(Upper Limit of Normal) ALP ≤ 1.5 × ULN Serum bilirubin ≤ 1.5 × ULN Serum creatinine ≤ 1.5 × ULN 7. ECOG PS of 0 or 1 8. No concomitant medical, psychiatric or geographic problems that might prevent completion of treatment or follow-up 9. Before any study-specific procedures, the appropriate written informed consent must be obtained  Inflammatory breast cancer 2. Inoperable disease that is judged very unlikely to be rendered operable by neo-adjuvant treatment 3. Known severe hypersensitivity to GnRHa treatment 4. Bilateral invasive breast cancer 5. Other serious illness or medical condition congestive heart failure or unstable angina pectoris, previous history of myocardial infarction within 1 year from study entry, uncontrolled hypertension or high-risk uncontrolled arrhythmias history of significant neurologic or psychiatric disorders including psychotic disorders, dementia or seizures that would prohibit the understanding and giving of informed consent active uncontrolled infection 6. HRT within 4 weeks of starting treatment 7. Definite contra-indications for the use of corticosteroids. 8. Last 10 years with a history of other malignant tumor (except in the case of basal cell carcinoma or cervical carcinoma in situ, and where treatment consisted solely of resection) 9. Systemic metastatic (Tests for the diagnosis of systemic metastatic comply with the guideline in each institution) 10. Pregnant or breastfeeding women 11. Chronic oral treatment with corticosteroids unless initiated > 6 months prior to study entry and at low dose (≤ 20 mg methylprednisolone or equivalent)