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

• Evolution of femoral BMD after one year of treatment [ Time Frame: 1 year ] [ Designated as safety issue: No ]
• Evolution of lumbar spine and femoral BMD after two years of treatment [ Time Frame: 2 years ] [ Designated as safety issue: No ]
• Evolution of bone resorption and formation markers [ Time Frame: 2 years ] [ Designated as safety issue: No ]
• Proportion of fractures after two years of treatment [ Time Frame: 2 years ] [ Designated as safety issue: Yes ]
• Evolution of estradiol levels [ Time Frame: 2 years ] [ Designated as safety issue: No ]

Aromatase inhibitor therapy is in France the adjuvant reference treatment for postmenopausal women with early-stage breast cancer. This treatment induces bone loss and a higher risk of fractures.

This study aimed to document the effect of bisphosphonate therapy in preventing bone loss and osteoporotic fractures in postmenopausal women with aromatase inhibitor treatment for breast cancer

• Breast Cancer
• Menopause
• Osteopenia

• Drug: Risedronate
  35mg oral risedronate once per week for 24 months
• Drug: Placebo
  Placebo 35 mg once a week for 24 months

• Placebo Comparator: 2

  Patients receive placebo 35 mg once a week plus a calcium and vitamin D supplementation.

  Measure of bone density, bone markers, clinical examination and questionnaire regarding fractures will be assessed at 12 and 24 months of treatment

  Intervention: Drug: Placebo
• Active Comparator: 1

  Patients receive risedronate 35 mg once a week plus a calcium and vitamin D supplementation.

  Measure of bone density, bone markers, clinical examination and questionnaire regarding fractures will be assessed at 12 and 24 months of treatment

  Intervention: Drug: Risedronate

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