Zoledronate in Treating Osteopenia or Osteoporosis in Postmenopausal Women Receiving Letrozole for Stage I, Stage II, or Stage IIIA Primary Breast Cancer

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