Patients with prostate cancer and androgen deprivation therapy have increased risk of fractures—a study from the fractures and fall injuries in the elderly cohort (FRAILCO)

SUMMARY: Osteoporosis is a common complication of androgen deprivation therapy (ADT). In this large Swedish cohort study consisting of a total of nearly 180,000 older men, we found that those with prostate cancer and ADT have a significantly increased risk of future osteoporotic fractures. INTRODUCTION: Androgen deprivation therapy (ADT) in patients with prostate cancer is associated to increased risk of fractures. In this study, we investigated the relationship between ADT in patients with prostate cancer and the risk of incident fractures and non-skeletal fall injuries both compared to those without ADT and compared to patients without prostate cancer. METHODS: We included 179,744 men (79.1 ± 7.9 years (mean ± SD)) from the Swedish registry to which national directories were linked in order to study associations regarding fractures, fall injuries, morbidity, mortality and medications. We identified 159,662 men without prostate cancer, 6954 with prostate cancer and current ADT and 13,128 men with prostate cancer without ADT. During a follow-up of approximately 270,300 patient-years, we identified 10,916 incident fractures including 4860 hip fractures. RESULTS: In multivariable Cox regression analyses and compared to men without prostate cancer, those with prostate cancer and ADT had increased risk of any fracture (HR 95% CI 1.40 (1.28–1.53)), hip fracture (1.38 (1.20–1.58)) and MOF (1.44 (1.28–1.61)) but not of non-skeletal fall injury (1.01 (0.90–1.13)). Patients with prostate cancer without ADT did not have increased risk of any fracture (0.97 (0.90–1.05)), hip fracture (0.95 (0.84–1.07)), MOF (1.01 (0.92–1.12)) and had decreased risk of non-skeletal fall injury (0.84 (0.77–0.92)). CONCLUSIONS: Patients with prostate cancer and ADT is a fragile patient group with substantially increased risk of osteoporotic fractures both compared to patients without prostate cancer and compared to those with prostate cancer without ADT. We believe that this must be taken in consideration in all patients with prostate cancer already at the initiation of ADT.