Bone Management in Patients with Prostate Cancer: FRAX Combined with Bone Mineral Density Can Prevent Unnecessary Treatment

INTRODUCTION AND OBJECTIVES: Osteoporosis is a common consequence of androgen deprivation therapy (ADT) for prostate cancer. Up to 20% of men on ADT have suffered from fracture within 5 years. The WHO Fracture Risk Assessment Tool (FRAX) has been utilized to predict the 10-year probability of major osteoporotic and hip fracture. However, no large studies assessing the utility of FRAX with versus without dual-energy X-ray absorptiometry (DEXA) in prostate cancer patients have been performed. We validated the usefulness of FRAX combined with DEXA in men with prostate cancer. METHODS: FRAX was done in a total of 1,220 prostate cancer patients including those who underwent brachytherapy (n=547), radical prostatectomy (n=200), external beam radiation therapy (n=264), hormonal therapy only (n=187), and definitive treatment along with hormonal therapy (n=645) in Yokohama City University Hospital. Of these, 109 patients received DEXA. RESULTS: In men without receiving DEXA, the median (mean ± SD) risks for major osteoporotic and hip fracture were 8.5% (9.3 ± 4.8) and 3.2% (4.2 ± 3.9), respectively. One hundred sixteen (9.5%) and 634 (52.0%) of these patients had the major osteoporotic risk of more than 15% and hip fracture risk of more than 3%, respectively. In contrast, in men with DEXA, the median (mean ± SD) risks for major osteoporotic and hip fracture were 5.3% (5.4 ± 2.1) and 0.85% (1.3 ± 1.2), respectively. Two (0.2%) and 4 (8.0%) of these patients had the major osteoporotic risk of more than 15% and hip fracture risk of more than 3%, respectively [Table1]. In the same cohort who received DEXA, the risks for major osteoporotic (p < 0.001) and hip (p < 0.001) fracture were significantly lower in men with DEXA than in those without DEXA. CONCLUSIONS: Our results suggest that FRAX combined with DEXA might prevent unnecessary osteoporosis medication in prostate cancer patients.