Temporal declines in bone mineral density and trabecular bone score during androgen deprivation therapy

The trabecular bone score (TBS) has emerged as a convenient measure for assessing the microstructure of trabecular bone in the second through fourth lumbar vertebrae (L2-4) and can be conducted concurrently with bone mineral density (BMD) assessment. This study was performed to evaluate changes in BMD and the TBS during ADT for prostate cancer.

Consecutive patients who had prostate cancer without bone metastases at Kobe University Hospital were studied from March 2020 to December 2021. BMD and TBS were measured every 6 months from the start of treatment using Hologic Horizon devices (Hologic, Inc., Marlborough, MA, USA).

Thirty-four patients were followed for 2 years. Significant declines in BMD (-3.8% for femoral neck, -4.2% for total hip, and -6.1% for lumbar spine) and TBS (-16.6%) were noted after 2 years of ADT. Correlation analyses revealed a weak correlation between lumbar spine BMD and TBS at ADT initiation, but this correlation strengthened after 2 years. The multiple regression analysis results suggested that the rate of BMD loss may be slower in patients with a preserved pretreatment TBS.

In patients without bone metastases undergoing ADT for prostate cancer, notable decreases were found in both BMD and TBS over a 2-year treatment period. Factors influencing the TBS decline remain unclear; however, patients with a lower pretreatment TBS exhibited a more rapid decline in BMD.