Timing of androgen deprivation therapy use and fracture risk among elderly men with prostate cancer in the United States.

PURPOSE

Fractures are a recognized consequence of androgen deprivation therapy (ADT); however, less is known about the incidence of fracture in relation to the timing of ADT use or the impact of fracture on mortality in men with prostate cancer.

METHODS

Using data from the Surveillance, Epidemiology, and End Results-Medicare linked database, we estimated adjusted hazard ratios (aHRs) using time-dependent Cox regression for fracture incidence related to the recency of exposure and dose among prostate cancer patients on gonadotropin-releasing hormone (GnRH) agonists, as well as mortality associated with fractures.

RESULTS

In our cohort of 80 844 patients, ADT was associated with an increased rate of fracture in both non-metastatic patients (aHR = 1.34; 95% confidence interval [CI] = 1.29-1.39) and metastatic patients (aHR = 1.51; 95%CI = 1.36-1.67). Fracture rates increased with increasing cumulative GnRH dose but decreased with increasing number of months since last use in each dose category. The mortality rate doubled for men experiencing a fracture after their diagnosis compared with that for men who did not experience a fracture (aHR = 2.05; 95%CI = 1.98-2.12).

CONCLUSIONS

ADT in elderly men with prostate cancer increased the incidence of fractures, and the effect appears to diminish with increasing time since the last dose of a GnRH agonist. Experiencing a fracture after the diagnosis of prostate cancer was associated with decreased survival.