['metastatic breast cancer']
['everolimus(afinitor)', 'letrozole', 'leuprolide(lorelin depot)']

        Inclusion Criteria:

          -  Age ≥ 20 years

          -  Histologically or cytologically confirmed, HER-2 negative breast cancer with recurrent
             or metastatic disease

          -  No HER2 overexpressing breast cancer

          -  Premenopausal status, defined as either

          -  ER and/or PR positive

          -  Progressive disease on tamoxifen treatment or sequential or combined treatment of
             tamoxifen and GnRH agonist as a palliative or an adjuvant endocrine treatment

          -  Duration of tamoxifen treatment should be at least 3 months or more

          -  No prior treatment with an aromatase inhibitor or inactivator or fulvestrant, or mTOR
             inhibitors

          -  One line of chemotherapy in metastatic setting is permitted

          -  ECOG performance status 0,1 or 2

          -  At least one measurable lesion or mainly lytic bone lesions in the absence of
             measurable disease

          -  Adequate hematologic, liver and kidney function

        Exclusion Criteria:

          -  Pregnant women or patients in lactation

          -  More than one line of prior chemotherapy for metastatic breast cancer

          -  GnRH agonist with tamoxifen treatment within 2 weeks.

          -  Active malignancy other than breast cancer, in situ carcinoma of the cervix,
             controlled resected thyroid well differentiated carcinoma or non-melanomatous skin
             cancer in the past 5 years

          -  Active cardiovascular disease such as angina, ventricular tachycardia, uncontrolled
             hypertension

          -  Active uncontrolled infection

          -  Symptomatic brain metastases

          -  Lymphangitic carcinomatosis involving >50% of the lungs

          -  Evidence of metastases involving more than one third of the liver on sonogram or CT

          -  Patients not able or unwilling to give informed consent
      