3D dual-energy x-ray absorptiometry (DEXA) is a valuable tool for detecting bone changes in prostate cancer patients receiving androgen deprivation therapy, researchers have reported.
The finding is from a study of 41 patients who received androgen deprivation therapy (ADT) for one year and underwent DEXA scans both before and after treatment, noted lead author Ji Yong Park, MD, of Chonnam National University Medical School in Gwangju, South Korea, and colleagues. The work was published September 24 in the Journal of Bone Oncology.
“One year of ADT exerts a substantial detrimental effect on bone strength, leading to reductions in areal [bone mineral density], [volumetric bone mineral density], and adverse changes in hip geometry,” the group wrote.
ADT is a cornerstone treatment for prostate cancer and is well known to accelerate bone loss by reducing sex steroid levels, with patients having a 1.6-fold increased risk of fractures compared to those not receiving the therapy, the authors explained.
While DEXA is the most widely used clinical tool for assessing bone strength via areal BMD measurements, it does not capture bone quality or distinguish between trabecular and cortical bone compartments, which are important for determining risk of fractures, they noted.
Conversely, 3D DEXA uses statistical shape and density modeling software (3D-Shaper, 3D Shaper Medical) to obtain these measurements by reconstructing 3D representation of the hip from 2D DEXA images.
In this study, the researchers obtained 2D DEXA scans from 41 patients (mean age, 75.5 years old) taken before and one year after ADT. In addition to areal BMD, they used 3D-Shaper to measure trabecular and cortical volumetric BMD, integral volumetric BMD (trabecular plus cortical), cortical surface BMD (sBMD), cortical thickness, and hip structural parameters.
After one year of ADT, the investigators noted significant reductions in areal BMD at the lumbar spine (–4.5, p < 0.001) and total hip (–3.7, p < 0.001). 3D-DXA analysis revealed significant declines in integral volumetric BMD (–3.8) and trabecular volumetric BMD (–4.9; both p < 0.001). In addition, cortical surface BMD decreased significantly by –2.7 (p < 0.001) and cortical thickness decreased significantly at the total hip by –1.2 (p = 0.011).
“To the best of our knowledge, this is the first study to report changes in hip [volumetric] BMD and [hip structural analysis] using 3D modeling derived from hip DEXA in ADT patients,” the group wrote.
Ultimately, volumetric BMD and other bone measurements obtained in this study can be assessed using advanced imaging techniques such as quantitative CT (QCT) or high-resolution peripheral QCT, yet their clinical utility is limited by high cost and radiation exposure, the researchers noted.
“Thus, 3D DEXA may represent a practical and valuable tool for detecting structural bone changes in prostate cancer patients undergoing ADT,” the group concluded.
The full study is available here.