Bone Mineral Density in Postmenopausal Women at Increased Risk of Breast Cancer And Who Are Receiving Exemestane on MAP3

Increased bone turnover may be a risk factor for fracture \[Lønning 2005\]. However, it is uncertain whether markers of bone resorption and markers of bone formation are both associated with fracture risk \[Looker 2000\]. Therefore, we will measure bone formation and bone resorption markers at baseline, year 1 and year 5. Blood specimens will be shipped to and stored in a central laboratory for future assays of bone biomarkers. For markers of bone formation, the N-terminal Propeptide of Type I Collagen (PINP) will be measured. For bone resorption markers, serum levels of cross-linked N-telopeptides of type I collagen (NTx) will be measured. Note: Subjects must fast 12-14 hours prior to blood draw.

BMD of the spine (L1-L4) and total hip will be done within 12 months prior to randomization to the MAP.3 core protocol. BMD by DEXA of the spine (L1-L4) and total hip will be repeated at year 2 and year 5 of the MAP.3 core study on the same Lunar or Hologic scanner.