Bone Health and Coronary Heart Disease in Postmenopausal Women with Breast Cancer Treated with Tamoxifen: A Dissertation

Breast cancer, osteoporosis, and coronary heart disease (CHD) are three major threats to women’s health. Postmenopausal women with breast cancer are also at high risk for osteoporosis and CHD. Adjuvant tamoxifen therapy is not only an effective treatment for breast cancer, but has been shown to have a beneficial effect on bone and the cardiovascular system. Although tamoxifen has been convincingly demonstrated to be able to preserve bone mineral density (BMD), an unexpected increase of risk of fractures in patients treated with tamoxifen has been reported. The findings of the association of tamoxifen and CHD from previous studies were either borderline or inconsistent. To clarify the discrepancy between BMD and fractures and test the potential beneficial effect of tamoxifen on CHD, I conducted a series of retrospective studies in postmenopausal women with breast cancer who participated in the Cancer Surveillance in HMO Administrative Data (IMPACT study) or the Study of Osteoporotic Fractures (SOF). In patients who participated in the IMPACT study, I demonstrated that the association of tamoxifen and fracture incidence varied at different skeletal sites. Although the association of tamoxifen and fractures in the spine (HR=0.40, 95% CI: 0.09-1.85), wrist (HR=2.49, 95% CI: 0.88-7.06), and total body (HR=0.87, 95% CI: 0.49-1.55) was inconclusive, tamoxifen was associated with an apparent