The Risk of Fracture in Patients Undergoing Androgen Deprivation May Be Overstated: Analysis of an Unselected Cohort of Patients

Objective: In this study we examined the prevalence of fracture among men undergoing ADT for prostate cancer to determine if the fracture risk was increased among this population. Background: Androgen deprivation therapy (ADT) is a therapeutic approach for men with various prostate cancer disease states. Treatment-related side effects of ADT include rapid bone loss. Previous studies have found that the bone loss related to ADT leads to the development of fractures. Methods: This is a retrospective cohort study of patients treated with ADT in a radiation oncology and medical oncology practice at an urban academic medical center from 2005 to 2010. Patients with evidence of bone metastases responsive to ADT were included. Those with androgen-independent prostate cancer were excluded. Results: One hundred thirty patients met the inclusion criteria and among them only three fractures occurred during 373 person-years of follow-up. The fracture-free survival (FFS) rate at three years for all was 97.7%. Excluding fractures occurring within six months of ADT initiation, the FFS rate was 100% at three years. No significant difference was demonstrated in those screened with a pretreatment dual-emission X-ray absorptiometry (DEXA) scan; there was no relationship between the number of ADT cycles, recovery of testosterone to normal, or total time on ADT. Older patients, surprisingly, had a lower risk (p = 0.054). Patients with normal bone mineral density (BMD) had an FFS rate of 93.8% at three years, osteopenic patients had 94.7%, and patients with osteoporosis and hormone-responsive metastases had 100%. Conclusion: The prevalence of fracture among this group is significantly less than what has previously been reported for men receiving ADT, potentially suggesting an overstatement of risk in the literature to date. Further prospective study with a larger sample size is needed.