Assessment of bone health in patients with prostate cancer using cancer staging computed tomography.

PURPOSE

To evaluate the utility of vertebral Hounsfield unit (HU) values from computed tomography (CT) in cancer staging as a supplementary screening tool for bone health among prostate cancer (PCa) patients.

METHODS

T-scores of bone mineral density (BMD) in each lumbar vertebra (L1-L4) and hip for newly diagnosed PCa patients (N = 139) were measured using dual-energy X-ray absorptiometry (DXA). The degenerative changes in each lumbar vertebra were assessed, and the HU values of trabecular bone in axial CT images of each vertebral body (vertebral CT-HU value) were measured using staging CT.

RESULTS

556 vertebrae were analyzed. 326 of 556 (59%) lumbar vertebrae had degenerative changes. The vertebral CT-HU value was positively correlated with the lumbar BMD T-score, with higher correlation coefficients observed in vertebrae without degenerative changes (r = 0.655, N = 230) when compared to vertebrae with degenerative changes (r = 0.575, N = 326). The thresholds matching BMD T-scores of - 2.0 and - 1.5 set by cancer treatment-induced bone loss guidelines were 95 HU and 105 HU, respectively. Based on the intervention threshold (lumbar BMD T-score <  - 1.5), 15.1% of PCa patients required osteoporosis treatment; and, this value increased to 30.9% when L1-L4 CT-HU thresholds that corresponded to BMD T-score <  - 1.5 were used.

CONCLUSION

Lumbar BMD values from DXA may not reflect true bone health in PCa patients who often have lumbar degenerative diseases. Thresholds based on the vertebral CT-HU value can be used as a supplementary method to identify PCa patients who need anti-osteoporosis drugs.