Androgen deprivation therapy for prostate cancer and the risk of autoimmune diseases.

Background: Androgen deprivation therapy (ADT) has been a mainstay of treatment for advanced prostate cancer (PCa), but limited studies have been performed to investigate the association between ADT and autoimmune diseases.

Methods: We conducted a population-based nationwide cohort study of 17,168 patients newly diagnosed with PCa between 1996 and 2013 using the National Health Insurance Research Database (NHIRD) of Taiwan. Cox proportional hazards models with 1:1 propensity score-matched analysis were used to investigate the association between ADT use and the risk of autoimmune diseases. The autoimmune diseases included Graves' disease, Crohn's disease, psoriasis, systemic lupus erythematosus, rheumatoid arthritis, ankylosing spondylitis, Guillain-Barre syndrome, Sjogren's syndrome, myasthenia gravis, pernicious anemia, hereditary hemolytic anemia, polyarteritis nodosa, Celiac disease, uveitis, polymyalgia rheumatica, dermatomyositis, Hashimoto's thyroiditis, hypersensitivity vasculitis, Behcet's disease, polymyositis, alopecia areata, Wegener's granulomatosis, ulcerative colitis, autoimmune hemolytic anemia, pemphigus, multiple sclerosis, systemic sclerosis, Goodpasture syndrome, giant cell arteritis, thromboangitis obliterans, arteritis obliterans, and Kawasaki disease. The duration of ADT use as a time-dependent variable was also examined for its association with autoimmune diseases. We also performed six secondary analyses.

Results: Of the 17,168 selected PCa patients, 14,444 patients met all the inclusion and exclusion criteria. After propensity score matching, 5590 ADT users and 5590 non-ADT users were included in the study cohort. A propensity score-matched analysis (adjusted hazard ratio (aHR), 0.619, 95% confidence interval (CI), 0.51-0.75, P < 0.001) demonstrated a significantly decreased risk of autoimmune diseases in ADT users. A significant decrease in the risk of autoimmune diseases with increasing ADT duration was also demonstrated (P < 0.001).

Conclusions: We observed that ADT use in patients with PCa was associated with a decreased risk of autoimmune diseases. These novel findings provide a potential role for androgen deprivation therapy in the modification of inflammation and autoimmunity in Asian patients with prostate cancer.