Statement: Patients with Scoliosis with a Cobb angle exceeding 20 degrees at the lumbar spine, or with a prior surgery at the lumbosacral spine are excluded from the primary trial, as these would interfere with the necessary CT and MRI scans for the study.
Primary_evidence: DISEASE CHARACTERISTICS:   Diagnosis of localized breast cancer   Stage I-IIIA disease   Adequately treated breast cancer   No clinical or radiological evidence of recurrent or metastatic disease   Baseline total lumbar spine or femoral neck bone mineral density T-score < -2.0 standard deviation (e.g., a patient with a T score of -2.1 is eligible)   Hormone-receptor status:   Estrogen receptor and/or progesterone receptor-positive breast cancer   PATIENT CHARACTERISTICS:   Female   Postmenopausal, defined by 1 of the following criteria:   Age > 55 years with cessation of menses   Age  55 years with spontaneous cessation of menses for > 1 year   Age  55 years with spontaneous cessation of menses for  1 year, but amenorrheic (e.g., spontaneous or secondary to hysterectomy), AND has postmenopausal estradiol levels   Bilateral oophorectomy   ECOG performance status 0-2   Life expectancy  5 years   WBC  3,000/mm³ OR granulocyte count  1,500/mm³   Platelet count  100,000/mm³   Alkaline phosphatase  3 times upper limit of normal (ULN)   AST  3 times ULN   Creatinine < 2.0 mg/dL   Creatinine clearance  45 mL/min   No hypercalcemia (i.e., calcium level > 1 mg/dL above ULN) OR hypocalcemia (i.e., calcium level > 0.5 mg/dL below lower limit of normal) within the past 6 months   No other malignancy within the past 5 years except adequately treated basal cell or squamous cell skin cancer or carcinoma in situ of the cervix   No other nonmalignant systemic diseases, including any of the following:   Uncontrolled infection   Uncontrolled diabetes mellitus   Uncontrolled thyroid dysfunction   Disease affecting bone metabolism (hyperparathyroidism, hypercortisolism, Paget's disease, osteogenesis imperfecta)   Malabsorption syndrome   No uncontrolled seizure disorders associated with falls   No known hypersensitivity to zoledronate or other bisphosphonates, letrozole, calcium, or vitamin D   No concurrent active dental problems, including any of the following:   Infection of the teeth or jawbone (maxillary or mandibular)   Dental or fixture trauma   Prior or current diagnosis of osteonecrosis of the jaw   Exposed bone in the mouth   Slow healing after dental procedures   No contraindication to spine dual energy x-ray absorptiometry (DXA) as defined by any of the following:   History of surgery at the lumbosacral spine, with or without implantable devices   Scoliosis with a Cobb angle > 15 degrees at the lumbar spine   Immobility, hyperostosis, or sclerotic changes at the lumbar spine, or evidence of sclerotic abdominal aorta sufficient to interfere with DXA scan   Disease of the spine that would preclude the proper acquisition of a lumbar spine DXA   No condition that would preclude study follow-up or compliance   No psychiatric illness that would preclude giving informed consent   PRIOR CONCURRENT THERAPY:   More than 3 weeks since prior and no other concurrent oral bisphosphonates   No prior intravenous bisphosphonates   No prior aromatase inhibitor therapy   More than 6 months since prior anabolic steroids or growth hormone   More than 2 weeks since prior and no concurrent inhibitor of osteoclastic bone resorption (e.g., calcitonin, mithramycin, or gallium nitrate)   More than 30 days since prior systemic investigational drug and/or device   More than 7 days since prior topical investigational drug   More than 6 weeks since prior and no concurrent dental or jaw surgery (e.g., extraction, implants)   Concurrent short-term corticosteroid therapy allowed   No concurrent sodium fluoride, parathyroid hormone, or tibolone   No other concurrent investigational drug or device