Bone Abstracts

Introduction: Aromatase inhibitors (AI) used as adjuvant treatment of hormone-sensitive breast cancer reduce the level of circulating estrogen and cause accelerated bone loss. The aim of this study is to investigate the prevalence of osteoporosis in women with breast cancer and the effect of chemotherapy on the risk of osteoporosis.

Methods: Three hundred and sixty women with hormone-sensitive breast cancer who were scheduled to start treatment with AI were included. BMD was measured by DXA, information regarding risk factors for osteoporosis and chemotherapy was obtained by questionnaires and from patient files.

Results: One hundred and five women had been treated with chemotherapy and prednisolone (30%). They were younger than the group not treated with chemotherapy; mean age 57±6 vs 67±7 years (P<0.001) and had lower BMD Z-scores at the lumbar spine (−0.12±1.24 vs 0.78±1.40), femoral neck (−0.36 ±1.11 vs 0.14 ±1.07) and total hip (−0.18 ±0.97 vs 0.35 ±1.04) (P<0.001). The prevalence of osteoporosis was 18 and 14% among women who had or had not received chemotherapy (NS). Regression analyses revealed that BMD was influenced by BMI (P<0.001), previous fracture (P<0.05) and chemotherapy (P=0.08) at the lumbar spine and by BMI (P<0.001), smoking (P<0.001) and age (P<0.001) at the hip sites. If only women with one of the following risk factors; previous fracture, smoking, BMI<25, age >70 years were referred for DXA, we would identify 87% of patients with osteoporosis and reduce the need for DXA by 25%. If chemotherapy was added as a risk factor, the corresponding figures would be 93 and 16%.

Conclusion: Women with breast cancer treated with chemotherapy had reduced BMD. This could be due to the chemotherapy and prednisolone treatment but it could also reflect that these women have a more aggressive cancer which could cause bone loss as part of generalized catabolism.