FEMORAL FRACTURES IN POSTMENOPAUSAL BREAST-CANCER PATIENTS TREATED WITH ADJUVANT TAMOXIFEN

The anti-estrogen tamoxifen is the prevalent endocrine treatment in po stmenopausal breast cancer patients. However, nothing is known about t he long-term effects of the drug on the skeleton as assessed by the oc currence of fractures. We investigated the occurrence of fractures of the femur in patients from a Danish Breast Cancer Cooperative Group (D B CG) trial initiated in 1977 by a linkage of data from the Danish Nat ional Registry of Patients with data from the DBCG registry. 1716 post menopausal women with high-risk breast cancer were randomized to local radiotherapy with or without tamoxifen, 30 mg daily for 1 year. Fifty -one patients in the control group had one femoral fracture and 64 tam oxifen treated patients had one femoral. fracture. Eleven patients in the control group had one trochanteric fracture compared to 27 patient s in the tamoxifen group (logrank = 5.28, P = 0.022; hazard ratio = 2. 12, 95% CL 1.12, 4.01). The results could not be explained by a longer survival in the tamoxifen group nor by bone metastases with pathologi cal fractures. In conclusion, our study suggests that tamoxifen does n ot seem to offer protection against fractures in old age and may even increase the risk of fractures at particular sites. This hypothesis ne eds to be disproved or confirmed in other trials.