Bone Mineral Density in Postmenopausal Women With Primary Breast Cancer Who Are Receiving Treatment on Clinical Trial

DISEASE CHARACTERISTICS:

* Enrolled in and meets eligibility requirements for protocol CAN-NCIC-MA27
* Acceptable quality dual-energy x-ray absorptiometry (DEXA) of the L1-L4 postero-anterior spine and hip within 12 weeks prior to randomization on protocol CAN-NCIC-MA27
* Hormone receptor status:

  * Estrogen receptor- and/or progesterone receptor-positive tumor

PATIENT CHARACTERISTICS:

* Female
* Postmenopausal
* No malabsorption syndrome
* No known cholecalciferol (vitamin D) deficiency, active hyper- or hypoparathyroidism, or Paget's disease
* No uncontrolled thyroid disease, Cushing's disease, or other pituitary disease
* No other bone disease (including osteomalacia or osteogenesis imperfecta)

PRIOR CONCURRENT THERAPY:

* More than 6 months since prior drugs (investigational or not), including bisphosphonates, for the prevention of osteoporosis (stratum I)
* More than 12 months since prior and no concurrent anticonvulsants
* More than 6 months since prior and no concurrent corticosteroids at doses \> 5 mg/day of prednisone (or equivalent) for \> 2 weeks
* More than 12 months since prior and no concurrent anabolic steroids
* No prior bisphosphonates (stratum II)
* No concurrent sodium fluoride at daily doses ≥ 5 mg/day
* No long-term (i.e., \> 6 months) use of coumarins
* No concurrent drugs (investigational or not), including bisphosphonates, for the prevention of osteoporosis (for patients with no osteopenia or osteoporosis \[stratum I\])