Bone Health in Postmenopausal Women Treated with Adjuvant Aromatase Inhibitors for Early Breast Cancer: 12 Months Follow-Up.

Abstract

Abstract Background:The use of aromatase inhibitors (AI) in the adjuvant setting for postmenopausal women with receptor-positive breast cancer is well established. The AI treatment has been associated with decline in bone mineral density (BMD), and increased bone turnover markers. We designed a prospective study to evaluate the effect of oral bisphosphonates (BP) on vertebral and non vertebral fractures (VF), bone turnover markers (bTM), BMD, and quality of life (QoL) in postmenopausal women receiving adjuvant AI for hormone receptor positive early breast cancer.Material and methods:Postmenopausal, receptor-positive breast cancer women treated with AI as initial therapy [Letrozol (LET)] or after 2 or 5 years of tamoxifen [switched to exemestane (EXE)] were included. Patients were stratified by lumbar spine, femoral neck and total hip BMD to receive open-label treatment with BP, alendronate or risedronate, (if osteoporosis [T-score<-2,5] or osteopenia [T-score<-2.0] and 1 major risk factor, defined as group of high risk of fracture) or calcium and vitamin D supplementation (if normal BMD or T-score>-2.0 and no major risk factor). Levels of 25-OH vitamin D, N-telopeptide (NTx), bone alkaline phosphatase (bALP) and osteocalcin (OC) were measured at baseline, 3, 12 and 24 moths, and BMD and thoracic and lumbar spine X-rays were assesed at baseline, 1 and 2 years. QoL was evaluated by ECOS-16 questionnaire and a visual analogue scale used to evaluate arthralgia. Results:from 03/2006 to 03/2009, 261 patients have been included and 117 have completed >12 month follow up. All the bTM increased after 12 months of AI treatment and a significant decrease on BMD was also observed (Table 1). This effect is reverted with oral BP treatment, maintaining the BMD level and reducing the bTM. With the AI introduction QoL of patients became worse, and the BP treatment did not improve neither arthralgia nor bone pain. Osteoporotic fractures were recorded at baseline in 12.3% of women (4.2% VF and 7.7% non VF).Conclusions:AI treatment increased bone turnover, decreased BMD and QoL. Of note, BP use decreased bone turnover, has neutral effect in BMD and does not improve QoL. This study suggests that the current recommendation of the use of BP should be revisited to consider including all postmenopausal women treated with adjuvant AI to avoid increased bone turnover and bone mass decrease.Table 1. BMD at baseline, 12 months and changes Without BP (n=76) With BP (n=41) BMD value (g/cm2)AIBasal12 month% change / pBasal12 month% change / pFemoral NeckLET0.7650.751- 1.96 / 0.020.6480.657+ 1.61 / NS EXE0.7560.749- 0.6 / NS0.6260.644+ 2.63 / 0.013Lumbar spineLET0.9900.969- 2.36 / 0.00010.8150.813- 0.17 / NS EXE0.9570.940- 1.57 / 0.0430.8110.814+ 0.86 / NS Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 3175.