Bone Density and Bone Loss in Postmenopausal Women With Breast Cancer Receiving Treatment in Clinical Trial IBCSG-1-98

Bone Density and Bone Loss in Postmenopausal Women With Breast Cancer Receiving Treatment in Clinical Trial IBCSG-1-98

RATIONALE: Diagnostic procedures, such as bone mineral density testing and x-ray, help measure bone loss in women receiving treatment for breast cancer. The test results may help doctors plan better treatment. PURPOSE: This phase III trial is studying bone density and bone loss in postmenopausal women with breast cancer receiving treatment in clinical trial IBCSG-1-98.

OBJECTIVES: Compare the effects on bone mineral density (BMD) in the L2-L4 (posterio-anterior) region of the spine and hip by assessing bone density in postmenopausal women with breast cancer receiving treatment on protocol IBCSG-1-98. Compare the incidence of radiological gross changes and fractures identified from spine x-rays (T4-L4) in these patients (in groups 1 and 2). Use longitudinal BMD measurements to estimate a linear rate of bone loss based on mixed effect models. Identify serum markers for bone loss to determine how they correlate with osteoporosis, microfractures, clinical fractures, and breast cancer-related bone events. OUTLINE: This is a multicenter study and a substudy of protocol IBCSG-1-98. Patients are assigned to 1 of 3 groups according to the length of treatment they have undergone on protocol IBCSG-1-98. Group 1 (prior to or at the end of the second year of treatment on protocol IBCSG-1-98): Patients undergo bone mineral density (BMD) testing of the L2-L4 spine and hip at baseline and years 1, 2, 3, and 4 from baseline. They also undergo x-rays of the T4-L4 spine at baseline and years 1, 3, and 4 from baseline. Group 2 (after 2 years but before the end of the third year of treatment on protocol IBCSG-1-98): Patients undergo BMD testing of the L2-L4 spine and hip at baseline and years 1, 2, and 3 from baseline. They also undergo x-rays of the T4-L4 spine at baseline and years 2 and 3 from baseline. Group 3 (after 3 years but before the end of the fifth year of treatment on protocol IBCSG-1-98): Patients undergo BMD testing of the L2-L4 spine and hip at baseline and years 1 and 2 from baseline (for patients in 4th year of treatment) or year 1 from baseline (for patients in 5th year of treatment). Patients undergo blood collection at baseline and periodically during study for biomarker correlative study. PROJECTED ACCRUAL: A total of 660 patients will be accrued for this study.

Relative percent change of bone mineral density (BMD) form baseline to after 2, 3, 4, or 5 years of treatment on protocol IBCSG-1-98

Relative percent change in markers of bone resorption from baseline to after 2, 3, 4, or 5 years of treatment on protocol IBCSG-1-98

Recovery of the markers of bone resorption at 1 year after the completion of treatment on protocol IBCSG-1-98

DISEASE CHARACTERISTICS: Diagnosis of breast cancer Resected disease Enrolled on protocol IBCSG-1-98 Receiving adjuvant endocrine therapy comprising 1 of the following regimens: Letrozole Tamoxifen Letrozole after 2 years of tamoxifen Tamoxifen after 2 years of letrozole Not yet completed 5 years of treatment No breast cancer recurrence or second primary cancer No known, symptomatic bone disease, including osteomalacia or osteogenesis imperfecta No prior registration to protocol IBCSG-1-98 Bone Mineral Density substudy Hormone receptor status: Estrogen receptor-positive and/or progesterone receptor-positive tumor PATIENT CHARACTERISTICS: Female Postmenopausal No uncontrolled thyroid or parathyroid disease, Cushing's disease, or other pituitary diseases No malabsorption syndrome or clinically relevant vitamin D deficiency No patients for whom the bone density determination is impossible PRIOR CONCURRENT THERAPY: See Disease Characteristics More than 1 year since prior and no concurrent anticonvulsants More than 6 weeks since prior and no concurrent corticosteroids (at doses > the equivalent of 5 mg/day prednisone) for > 2 weeks total No prior or concurrent sodium fluoride (at daily doses ≥ 5 mg/day) for > 1 month More than 12 months since prior and no concurrent anabolic steroids More than 6 months since prior treatment, either investigational or not, for the prevention of osteoporosis (excluding calcium or cholecalciferol [vitamin D]) No concurrent raloxifene Concurrent therapeutic intervention for osteoporosis comprising bisphosphonates allowed Concurrent warfarin allowed provided it is given for ≤ 4 weeks

Decensi A, Sun Z, Guerrieri-Gonzaga A, Thurlimann B, McIntosh C, Tondini C, Monnier A, Campone M, Debled M, Schonenberger A, Zaman K, Johansson H, Price KN, Gelber RD, Goldhirsch A, Coates AS, Aebi S. Bone mineral density and circulating biomarkers in the BIG 1-98 trial comparing adjuvant letrozole, tamoxifen and their sequences. Breast Cancer Res Treat. 2014 Apr;144(2):321-9. doi: 10.1007/s10549-014-2849-2. Epub 2014 Feb 1.