DISEASE CHARACTERISTICS:

• At increased risk of developing breast cancer and enrolled on clinical trial CAN-NCIC-MAP3
• Bone mineral density (BMD) (as measured by dual x-ray absorptometry [DEXA] scans within 12 months prior to randomization to the core protocol [MAP.3]) T score > -2.0 standard deviation (i.e., 2.0 standard deviations below the average peak BMD of a young adult woman) of spine (L1-L4) and total hip
• Blood samples for baseline bone biomarkers collected within 8 weeks prior to randomization to CAN-NCIC-MAP3
• Serum for bone biomarkers (i.e., serum N-telopeptide and serum amino-terminal procollagen 1 extension peptide) must have been obtained within 8 weeks prior to registration to the study

PATIENT CHARACTERISTICS:

• Postmenopausal, defined as one of the following:

  • Over 50 years of age with no spontaneous menses for at least 12 months before study entry
  • 50 years of age or under with no menses (spontaneous or secondary to hysterectomy) for at least 12 months before study entry AND with follicle-stimulating hormone level within postmenopausal range
  • Underwent prior bilateral oophorectomy
• Available for collection of serum samples and BMD (DEXA) scans at the protocol defined times (i.e., have BMD scans at years 2 and 5 at the same site)
• No history of fragility fractures (i.e., a broken bone that occurs with a fall from a standing height or lesser amount of trauma)
• No malabsorption syndrome (e.g., untreated celiac disease, clinically relevant vitamin D deficiency, or active hyper- or hypoparathyroidism)
• No Paget disease or other metabolic bone diseases (e.g., osteomalacia or osteogenesis imperfecta)
• No Cushing disease or other pituitary diseases
• No inflammatory disease(s) (e.g., inflammatory bowel disease, rheumatoid arthritis, lupus, psoriasic arthritis, ankylosing spondylitis, or autoimmune hepatitis)

PRIOR CONCURRENT THERAPY:

• More than 3 months since prior bone drugs, such as bisphosphonates, teriparatide (parathyroid hormone [PTH]), sodium fluoride, calcitonin (Miacalcin®), strontium, or high-dose vitamin D (i.e., vitamin D3 > 2,000 IU/day or calcitriol)
• No prior bisphosphonate therapy duration of more than 6 months total during lifetime
• No concurrent anabolic or chronic oral corticosteroids (the equivalent of 5 mg of prednisone a day or higher for more than 2 weeks within the past 6 months and will likely require ongoing therapy)
• Concurrent inhaled steroids allowed

• No concurrent medication that may have an effect on study endpoints for this study, including any of the following:

  • Anticonvulsants
  • Sodium fluoride at daily doses > 5 mg/day for a period exceeding 1 month
  • Anabolic steroids
  • Teriparatide (parathyroid hormone)
  • Bisphosphonates, except for women who develop osteoporosis while on this study; these patients may be advised to start bone medication (i.e., strontium, calcitonin, or high-dose Vitamin D (i.e., Vitamin D3 > 2000 IU/day or calcitriol) at the discretion of their physician