Impact of aromatase inhibitor treatment on vertebral morphology and bone mineral density in postmenopausal women with breast cancer

Objective: The aim of this study was to evaluate the impact of aromatase inhibitor (AI) treatment on vertebral morphology by vertebral fracture assessment in postmenopausal women with early-stage breast cancer. Methods: A clinical cross-sectional study was conducted. A group of 156 postmenopausal women with breast cancer (mean [SD] age, 60.4 [10.1] y; mean [SD] time since menopause, 11.7 [9.2] y) was included in the study. Eighty-two women received AI treatment, whereas 74 women did not. Women underwent extensive medical history check and risk factor assessment together with vertebral morphology and bone mineral density (BMD) evaluation. Results: In the studied population, the prevalence of vertebral fractures identified by vertebral fracture assessment was 16.6%. Multivariate analysis showed that AI treatment was significantly associated with vertebral fractures (adjusted P<0.04). Women receiving AI treatment had a higher prevalence of vertebral fractures than women not treated with AIs (25.6% vs 4%). The risk of vertebral fractures in women treated with AIs was significantly higher than in non-AI-treated women (adjusted odds ratio, 4.7; P<0.005). Vertebral fractures of the highest grade were identified at the lumbar spine. Women treated with AIs had a significantly lower BMD than women not treated with AIs (P<0.01). Reduction of BMD was significantly associated with length of therapy, whereas there was no association between length of treatment and risk of vertebral fractures. Conclusions: AI treatment severely impacts vertebral morphology. Our study demonstrates a high prevalence of asymptomatic vertebral fractures in women treated with AIs.