Study of Bone Mineral Density in Women With Breast Cancer Treated With Triptorelin and Tamoxifen or Exemestane on Protocol IBCSG 25-02

OBJECTIVES: * Evaluate changes in bone mineral density (BMD) among premenopausal women randomized in protocol IBC SG-25202 (TEXT-2) to receive either: A) triptorelin (GnRH analogue) for 5 years plus tamoxifen for 5 years; or B) triptorelin (GnRH analogue) for 5 years plus the steroidal aromatase inhibitor exemestane for 5 years. * Evaluate serial serum markers for bone remodeling (C-telopeptide, osteocalcin, bone-specific alkaline phosphatase) and investigate their correlation with BMD. * Evaluate the relationship of genetic variants of CYP19A1, ERα, ERß, and IGF 1 with BMD. * Evaluate serial serum growth factors (IGF-1 and IGFBP-3) and investigate whether their time course correlates with BMD. * Explore the role of serum IGF-1 and IGFBP-3 as biomarkers of disease outcome (disease-free survival). (exploratory) OUTLINE: Blood samples are collected at baseline and then periodically for 6 years. Serum markers of bone remodeling and serum growth factor levels are measured. Bone mineral density in the L1-L4 (postero-anterior) region of the spine and femoral neck of the hip is measured by DEXA at baseline and then periodically for 6 years. Any surplus serum is stored for use in unspecified future research.