High prevalence of vertebral fractures in women with breast cancer starting aromatase inhibitor therapy.

BACKGROUND The purpose of this study was to describe bone status in a large cohort of postmenopausal women with nonmetastatic breast cancer, at the initiation of aromatase inhibitor therapy. PATIENTS AND METHODS A prospective, transversal and clinical study was conducted. Each woman had an extensive medical history, a biological evaluation, a bone mineral density (BMD) measurement and spinal X-rays. RESULTS Four hundred and ninety-seven women aged 63.8 ± 9.6 years were included in this study. Eighty-five percent of these women had a 25-OH vitamin D concentration <75 nmol/l. One hundred and fifty-six women (31.4%) had a T-score < -2 at one of the three site measurements. Ninety-five women (19.1%) had a history of nonvertebral fracture with a total of 120 fractures. Spine X-rays evaluation revealed that 20% of the women had at least one vertebral fracture. The presence of vertebral fracture was associated with nonvertebral fracture history [odds ratio (OR) 1.6, 95% confidence interval (CI) 1.1-2.4] and with spine BMD (OR 1.4, 95% CI 1.1-1.7). The prevalence of vertebral fracture reached 62.9% in women with age above 70 years and femoral T-score < -2.5. CONCLUSION Before starting aromatase inhibitor therapy for breast cancer, a large proportion of women had a vitamin D insufficiency and vertebral fractures.