Bone health in postmenopausal women with early breast cancer: how protective is tamoxifen?

Breast cancer is a leading threat to women's health. Tamoxifen, the most successful selective estrogen receptor modulator, has been used in hormonal therapy for three decades. Along with its therapeutic effect on breast cancer, tamoxifen also demonstrates potential benefits for bone health. However, the extent and quality of such benefits have not been systematically evaluated. We conducted a comprehensive literature search and identified 27 peer-reviewed articles investigating the relationship between tamoxifen and bone health in postmenopausal women with early stage breast cancer. The majority of studies reported that tamoxifen therapy alone protected against the loss of spinal bone mineral density. The bones in the hip also benefited from tamoxifen treatment while there was no evidence demonstrating tamoxifen's protection against bone loss in arms. When tamoxifen was combined with chemotherapy, it was found to partially prevent or reverse the bone loss resulting from chemotherapy. Patients with a history of hormone replacement therapy experienced bone loss while patients without the history had increased bone mineral density during tamoxifen therapy. Despite an apparent impact of tamoxifen on bone mineral density, the few available studies of tamoxifen and bone fractures appear to suggest no protective effect but an increase in fracture incidence. More investigation is necessary to clarify the discrepancy between bone mineral density and fracture in postmenopausal breast cancer patients treated with tamoxifen.