Relationship between androgen deprivation therapy and community-acquired respiratory infections in patients with prostate cancer

Objectives: To investigate the dose-dependent effect of androgen deprivation therapy on community-acquired respiratory infections in patients with localized prostate cancer. Methods: We identified 52 905 men diagnosed with localized prostate cancer within the Surveillance, Epidemiology and End Results-Medicare database between 1991 and 2006. We compared those who did not receive androgen deprivation therapy with those who received androgen deprivation therapy within 2 years of diagnosis, calculated as monthly equivalent doses (<7, 7-11, >11 doses), or orchiectomy. Adjusted Cox hazard models were fitted to predict the risk of community-acquired respiratory infections (acute sinusitis, acute bronchitis, [severe] pneumonia) in patients treated with medical androgen deprivation therapy versus orchiectomy versus none. Results: Overall, 43.4% received medical androgen deprivation therapy. These patients more likely experienced respiratory events compared with those who did not receive androgen deprivation therapy or who underwent orchiectomy (62.2% vs 54.5% vs 47.8%, P < 0.001). The risk of experiencing any respiratory event increased with the number of doses received. For example, men receiving >11 doses of androgen deprivation therapy were at greatest risk of acute sinusitis, acute bronchitis and pneumonia (HR 1.13, 1.26 and 1.15, respectively, all P < 0.001), except severe pneumonia. Furthermore, we did not detect any relationship between orchiectomy and respiratory events. Study limitations include the utilization of a retrospective population-based dataset. Conclusions: Increased exposure to medical androgen deprivation therapy for men with localized prostate cancer is associated with a higher risk of community-acquired respiratory infections. Our results suggest that respiratory complications represent potentially underreported complications of medical androgen deprivation therapy.