This study proposes to prove that the efficacy of adjuvant endocrine therapy for the premenopausal HR positive breast cancer patients is non-inferiority to adjuvant chemotherapy assessed by ultrasound response rate.

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