Bone Abstracts

Postmenopausal women with early stage hormone-receptor-positive breast cancer (EBC) are standardly treated with aromatase inhibitors (AIs). However, one side-effect of AIs treatment is a decrease in bone mineral density (BMD) and an increased risk of fracture. The objectives of this study were to examine: i) changes in bone formation (N-terminal propeptide of type I procollagen; PINP) and bone resorption (cross-linked C-telopeptides of bone type I collagen; CTX) markers, as well as changes in serum intact parathyroid hormone, 25 hydroxyvitamin D (25OHD) and plasma sclerostin levels over the first 6 months of AIs therapy in a cohort of breast cancer patients initiating aromatase inhibitors therapy and ii) the association between early changes in bone markers and subsequent BMD changes after 12 months of AIs treatment. Eligible breast cancer patients (n=50) were recruited and followed for 12 months. The results showed that low BMD and vitamin D insufficiency is highly prevalent among women with EBC treated with adjuvant AIs. AIs treatment was associated with significant increases in serum CTX (P<0.01) and plasma sclerostin (P<0.001) within the first 6 months and significant decreases in BMD at all measured sites (P<0.001) after 12 months. The changes in CTX were significantly (P<0.05) and negatively related with lumbar spine (r=0.309) and femoral neck (r=0.351) BMD changes. The changes in sclerostin were significantly (P< 0.05) and positively associated with femoral neck BMD changes (r=0.396). Conclusion: Findings from this study suggest the importance of early assessment of BMD and 25OHD levels when starting AIs treatment. Early identification of women with poor bone health and/or rapid increase of bone markers offer us possible intervention to prevent bone loss and fracture risk.