The efficacy of the use of denosumab in the prevention of aromatase inhibitor-induced bone loss in postmenopausal women with hormone receptor-positive breast cancer who are currently on or will iniate an aromatase inhibitor in the adjuvant setting

INTERVENTION: subcutaneous injection of denosumab every 6 months CONDITION: Breast Cancer PRIMARY OUTCOME: the percent change in lumbar spine(L1‐L4)BMD from baseline to 12 months SECONDARY OUTCOME: 1) the percent change in lumbar spine(L1‐L4)BMD from basebaline to 6 months,two years, three years, four years and five years.; 2) the percent change in total hip BMD from basebaline to 6 months, 12 months, two years, three years, four years and five years.; 3) To identify changes in serum markers of bone turnover, TRACP‐5b and BAP, from basebaline to 6 months, 12 months, two years, three years, four years and five years.; 4) Disease‐free survival; 5) Bone metastasis‐free survival; 6) Overall survival; 7) Distant recurrence‐free survival INCLUSION CRITERIA: 1) Adequately diagnosed and treated invasive breast cancer defined as 1.Clinical stage 1,2 or 3a 2.Patients with breast cancer whose tumor were removed by an appropriate surgical procedure such as mastectomy or breast conserving surgery 2) ER and PgR positive defined with immunohistochemical staining 3) Postmenopausal status defined by one of the following 1.women >54 years with cessation of menses 2.spontaneous cessation of menses within the past 1 years, but amenorrheic in women <55 years, and according to the definition of 'postmenopausal range' for FSH and estradiol level 3.bilateral oophorectomy 4) Lumbar spine, total hip or femoral neck BMD equivalent to a YAM classification of ‐1.0 to ‐2.5 5) ECOG Performance status of 0 to 2 6) Patients who have completed chemothrapy >4 weeks prior to study entry 7) Patients who have discontinued the following drugs known as affect to the skeleton more than 4 weeks oral bisphosphonates