Changes in femoral 3D-DXA cortical and trabecular indices in postmenopausal women with early breast cancer treated with aromatase inhibitors: a prospective study of the B-ABLE cohort

Objectives

This observational prospective study evaluated bone changes using 3D-DXA in the B-ABLE cohort of postmenopausal women with early breast cancer receiving aromatase inhibitors (AI).

Study design

Hip DXA scans were performed before initiating AI therapy and on a yearly basis until its completion: 5 years of AI therapy (5y-AI group) or 2–3 years of AI therapy after switching from 2 or 3 years of tamoxifen (pTMX-AI group). 3D-DXA analysis was performed using 3D-Shaper® software. Patients with osteoporosis or high fracture risk at baseline started antiresorptive treatment (ARP).

Main outcome measures

Cumulative changes in areal bone mineral density (aBMD) and 3D-DXA-derived parameters, including cortical surface BMD, cortical thickness, and integral, cortical, and trabecular volumetric BMD (vBMD), were evaluated by linear mixed models considering ARP and previous tamoxifen treatment.

Results

Of a total of 785 women included, 191 (24.3 %) started ARP at baseline. Non-ARP-treated patients had a decrease of more than 4 % in all bone parameters at the end of AI treatment, except cortical thickness, which displayed minimum changes. Women previously treated with TMX had significantly greater losses in most parameters, which occurred mainly during the first year of AI treatment.

In ARP-treated patients, a significant increase was detected in all bone parameters, especially in the 5y-AI group. Denosumab showed greater efficacy than bisphosphonate in improving most bone parameters.

Conclusions

3D-DXA provides deeper insights into the detrimental changes in the cortical and trabecular bone compartment caused by AI, and how ARP can prevent these effects.