Population-based assessment of hypogonadism and testosterone replacement therapy in hypogonadal men: is there a potential prostate cancer risk?

We sought to understand the relationship between hypogonadism and testosterone replacement therapy (TRT) in hypogonadal men on the risk of developing localized and metastatic prostate cancer. We used the Merative MarketScan database of commercial claims encounters to identify men diagnosed with hypogonadism. These men were matched to eugonadal men who served as controls. Multivariate negative binomial regression analysis of prostate cancer diagnoses, hypogonadism, and TRT in hypogonadal men adjusting for various known confounding factors was used understand the impact of hypogonadism and TRT on prostate cancer risk. We identified 3,222,904 men who met inclusion criteria, of which 50% were diagnosed with hypogonadism (1,611,452) and each were matched to a control (1,611,452). The incidence of prostate cancer was 2.16%, 1.55%, and 1.99% in controls, hypogonadal men on TRT, and hypogonadal men without TRT, respectively (p < 0.001). Untreated hypogonadism was independently associated with a decreased the risk of localized prostate cancer (IRR 0.46, 95% CI 0.43–0.50, p < 0.001) compared to eugonadal controls. Hypogonadal men on TRT also had a significantly decreased risk of localized prostate cancer (IRR 0.49, 95% CI 0.45–0.53, p < 0.001). Furthermore, hypogonadal men on TRT (IRR 0.21, 95% CI 0.19–0.24, p < 0.001) or without TRT (IRR 0.20, 95% CI 0.18–0.22, p < 0.001) both had significantly decreased risk of metastatic prostate cancer, respectively. Our population-based assessment suggests that untreated hypogonadism in men is associated with a 50% decreased incidence of localized prostate cancer and an 80% decreased incidence of metastatic prostate cancer. TRT in hypogonadal men was also associated with a decreased risk of subsequent prostate cancer. Further research is needed to better understand the relationship between testosterone deficiency and TRT in hypogonadal men on the of risk prostate cancer.