Risk of osteoporosis after adjuvant therapy for breast cancer

Breast cancer and osteoporosis are two of the most frequent diseases in Germany, affecting about 5-6 Million postmenopausal women. Estrogen may be the link between bone and the risk of breast cancer because of its potent effects on the mitotic activity of breast epithelium and on bone turnover. Depending on baseline BMD, the adjuvant therapy of premenopausal breast cancer patients can lead to a substantially increased risk of osteoporotic fracture. In postmenopausal women,the influence of chemotherapy on BMD is less pronounced. Endocrine therapy of hormone sensitive breast cancer using tamoxifene has been shown to have a protective effect on BMD. Third generation aromatase inhibitors,two non-steroid and one steroid, have recently been introduced into clinical practice. Recently, the results of the ATAC trial have demonstrated a significant increase in fracture risk for a non-steroidal preparation. The preclinical and recent clinical results of the steroid aromatase inhibitor on bone turnover show an opposite effect. Consequently, adjuvant therapy of pre- and postmenopausal women with breast cancer can lead to a significant decrease in BMD and an increased risk of osteoporotic fracture.