Study to Assess Efficacy of Risedronate in Preventing Bone Loss in Postmenopausal Women Treated for Breast Cancer

Inclusion criteria

• Postmenopausal women (more than one year since last menstrual period or removal of ovarian function by surgical or radiotherapic means)
• Operated for an invasive breast cancer (histologically proven)
• Surgical treatment completed and cycles of adjuvant chemotherapy (if necessary) completed
• Treated with aromatase inhibitor
• Osteopenic (-2.5<T score<-1) without osteoporotic fracture
• With written informed consent signed
• With social security

Exclusion criteria

• Women presenting a history of osteoporotic fracture or a T score less than -2.5 at at least one measure site
• Women presenting clinical signs of metastases
• Having received other hormonal treatment in the last 3 months
• Having received treatment by bisphosphonates, raloxifene, tamoxifen, parathormone, strontium ranelate, tibolone,calcitonin and corticosteroids at more than 5mg/d for 3 months in the last year
• Presenting a known and untreated hyperthyroid
• Presenting a known hyperadrenocorticism
• Patients treated and followed for Paget's disease of bone
• Presenting a untreated primary hyperparathyroid
• Presenting an indication against risedronate (known hypersensibility to risedronate monosodium and/or one of its excipients, non-corrected hypocalcemia, pregnancy or breast feeding, severe renal insufficiency inferior to 30 ml/min)
• Patients presenting malabsorption syndrome for glucose/galactose
• Person participating in another clinical trial concerning a medicine susceptible to influence bone mass