Endocrine Therapy vs Chemotherapy for Breast Cancer

Inclusion Criteria: * 35 years old \<age≤55 years old, in premenopausal status(with the judgement by researchers when the patients are recruited) Histologically confirmed primary invasive breast cancer * Stage: T2N0M0(cT\>2cm, SLNB negative), hard to proceed the breast conserving surgery(not feasible or may affect the appearance of breast) * Histologically confirmed HR+ (ER or PR positive, and \>50% cell in IHC) HER2 negative breast cancer by pathological evaluation * No other previous treatment for primary breast cancer * Without other tumor or unstable complication or uncontrolled infection * No contradiction for the third generation AIs, LHRHa, chemotherapy * Attend the study voluntarily, sign the informed consent. Exclusion Criteria: * Metastasis disease by pathological or radiological diagnosis * the history of other tumor * contradiction for the third generation AIs, LHRHa, chemotherapy * Contradiction for adjuvant chemotherapy: serious cardiology or cerebral vessel disease, liver or kidney disfunction, blood system disease, the other situation or complication that are not suitable or cannot adaptable for chemotherapy * Contradiction for proceeding surgery: contradiction for anesthesia, large lesion,T4, lymph node positive * other situation not suitable for the research: psychological disease, mental disorder, social problem, geographic problem * have been attendance in other anti-tumor treatment or other clinical trials 8) reject to attend the study