The Role of Distal Third Radius Dual Energy X-ray Absorptiometry (DXA) and Central DXA in Evaluating for Osteopenia and Osteoporosis in Men Receiving Androgen Deprivation Therapy for Prostate Cancer

Abstract The authors assessed the use of distal third radius dual energy X-ray absorptiometry (DXA) concomitantly with central (hip and lumbar spine) DXA to identify men with osteopenia or osteoporosis receiving androgen deprivation therapy (ADT) for prostate cancer. Initial classification with central DXA demonstrated 60 (17%) normal, 187 (55%) osteopenic, and 96 (28%) osteoporotic patients. Sixteen of 60 (27%) normal patients were reclassified as osteopenic (14) or osteoporotic (2), and 20 of 187 (11%) osteopenic patients were reclassified as osteoporotic with the combination of central DXA plus distal third radius DXA. The difference in reclassification was statistically significant. The addition of distal third radius to central DXA scanning in men with bone loss associated with ADT identifies a statistically significant number of men being reclassified as having osteopenia or osteoporosis. Combined central and distal third radius DXA scanning should be considered routine in the evaluation of all men suspected of bone loss associated with ADT. This has specific significant clinical relevance because of the large number of men with nonevaluable central DXA studies. Fracture risk prediction and treatment recommendations based on this reclassification will need to be determined by follow-up studies.