Session: SAT 224-247-Osteoporosis I
Poster Board SAT-232
Mangat NM, Lee S, Bruder JM
Introduction: Androgen deprivation therapy (ADT), used in the treatment of prostate cancer, is associated with accelerated bone loss and increased risk of fractures. It is recommended that men over the age of 50 years with osteoporosis diagnosed by bone mineral density (BMD) with a T-score of < -2.5 at the spine, total hip (TH), femoral neck (FN) or distal 1/3 radius (DR) or a fracture be considered for pharmacological therapy. If a patient has low bone density (T-score -1.0 to -2.5), then the FRAX® calculator is used to estimate an individual’s 10 year fracture risk probability. Predetermined cutoffs are used to guide therapy. Although not routinely measured, the BMD at DR will diagnose osteoporosis in more men with prostate cancer. Newer data has also suggested that in men with prostate cancer, the FRAX® calculator used without BMD identifies more men needing treatment than calculations with the BMD. Objective: The aim of our study was to determine if the FRAX® calculator used without BMD identifies the same individuals as BMD at the spine, TH, FN or DR and to compare the number of men identified for treatment vs. no treatment by each measurement. Materials & Methods: The BMD at the spine, TH, FN, and DR were measured as part of routine care in 510 men with prostate cancer, treated with ADT. The FRAX® calculator was used without BMD to estimate each individual’s 10 year fracture risk probability. Comparisons of BMD and the FRAX® calculator were done using the Pearson's Chi-Square test to determine the reliability (sensitivity and specificity) and positive (PPV) and negative predictive values (NPV). Results: The patient population had a mean age of 74.2 +8.6 with 62% Caucasian, 27% Hispanic and 12% Black. The mean height was 67.7+2.8 in and mean weight was 183.4+36.9 lbs. The mean BMD at the spine, TH, FN and DR was 0.60+0.009, 0.75+0.15, 0.92+0.20, and 0.73+0.14 g/cm2, respectively. The mean T-score at the spine, TH, FN and DR were -0.49+1.87, -1.56+1.54, -0.82+1.11, and -1.44+1.9, respectively. BMD at the spine and hip identified 140 men with osteoporosis, which increased to 216 men with the addition of the DR. 314 patients were identified to be at risk for fracture by using the FRAX® calculator without BMD. Of those 216 individuals diagnosed with osteoporosis by BMD, the FRAX® calculator identified 158 (73%) to be at risk for fracture, missed 58 men (30%), and identified an additional 156 men needing treatment. The accuracy of the 2 methods indicated a sensitivity of 73%, specificity 47%, PPV 50%, and NPV 30%. Conclusion: In men with prostate cancer, treated with ADT, using the FRAX® calculator without BMD identifies more individuals requiring therapy for osteoporosis than BMD alone. There was no association between BMD and the FRAX® calculator in identifying men needing treatment.
Nothing to Disclose: NM, SL, JMB
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