Androgen deprivation therapy (ADT), a treatment for prostate cancer, is associated with bone loss and fractures.
Dual energy x-ray absorptiometry (DXA) measured bone mineral density does not assess vertebral fractures (VF). High resolution microMRI (HR-MRI) assesses bone microarchitecture and provides structural information. To determine if VF identification increased the diagnosis of osteoporosis beyond DXA and if HR-MRI demonstrated skeletal deterioration in men with VF, we cross-sectionally studied 137 men ≥ 60 years with nonmetastatic prostate cancer on ADT for ≥6 months. Vertebral fracture assessment (VFA) by DXA was confirmed with x-rays. HR-MRI of the wrist included bone volume to total volume (BV/TV), surface density (trabecular plates), surface/curve ratio (plates/rods) and erosion index (higher depicts deterioration). VF were found in 37% of men; the majority were unknown. 7% of participants were classified as osteoporotic by hip or spine DXA. 37% of men without osteoporosis by DXA had VF identified, suggesting that 90% of patients with clinical osteoporosis would have been misclassified by DXA alone. By ANOVA comparison across VF grades, the BV/TV, surface density and spine, hip and wrist DXA were lower, and erosion index was higher in men with moderate-severe VF compared to lesser grades (all p< 0.05). By unadjusted ROC analysis, the addition of HR-MRI to DXA at the spine, hip and femoral neck, added substantially (AUC increased 0.831 to 0.902, p< 0.05) to prediction of moderate-severe vertebral fracture. HR-MRI indices were associated with spine, hip and wrist DXA measures (p< 0.01). Longer duration of ADT was associated with lower BV/TV, surface density and surface/curve ratio (p< 0.05). ADT for men with prostate cancer is associated with silent VF. DXA alone leads to misclassifications of osteoporosis which can be avoided by VF assessment. HR-MRI provides a novel technique to assess deterioration of structural integrity in men with VF and adds micro-structural information.
Written by:
Greenspan SL, Wagner J, Nelson JB, Perera S, Britton C, Resnick NM. Are you the author?
University of Pittsburgh, Division of Endocrinology, Pittsburgh, PA.
Reference: J Bone Miner Res. 2012 Sep 18. Epub ahead of print.
doi: 10.1002/jbmr.1771
PubMed Abstract
PMID: 22991066
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