Long-term Exposure to Testosterone Therapy and the Risk of High Grade Prostate Cancer

To our knowledge no population based studies have been done to examine whether long-term exposure to testosterone therapy is associated with an increased risk of high grade prostate cancer. We examined whether exposure to testosterone during a 5-year period was associated with an increased risk of high grade prostate cancer and whether this risk increased in a dose-response fashion with the cumulative number of testosterone injections.

Using SEER (Surveillance, Epidemiology and End Results)-Medicare linked data we identified 52,579 men diagnosed with incident prostate cancer between January 1, 2001 and December 31, 2006 who had a minimum of 5 years continuous enrollment in Medicare before the cancer diagnosis. We excluded patients diagnosed at death or after autopsy, those enrolled in a health maintenance organization in the 60 months before diagnosis and those with unknown tumor grade or tumor stage. In the 5 years before diagnosis 574 men had a history of testosterone use and 51,945 did not.

On logistic regression adjusting for demographic and clinical characteristics exposure to testosterone therapy was not associated with an increased risk of high grade prostate cancer (OR 0.84, 95% CI 0.67-1.05) or receipt of primary androgen deprivation therapy following diagnosis (OR 0.97, 95% CI 0.74-1.30). In addition the risk of high grade disease did not increase according to the total number of testosterone injections (OR 1.00, 95% CI 0.98-1.01).

Our finding that testosterone therapy was not associated with an increased risk of high grade prostate cancer may provide important information regarding the risk-benefit assessment for men with testosterone deficiency considering treatment.