Using testosterone-lowering drugs to treat prostate cancer may make men twice as likely to develop dementia within five years as patients whose testosterone levels were not tampered with, according to a retrospective study.
Testosterone has been associated with tumor growth and progression in patients with prostate cancer. Androgen deprivation therapy (ADT) has been used since the 1940s in an attempt to lower testosterone levels. In the United States, approximately half of all men with prostate cancer receive ADT as a part of their treatment regimens. However, studies have linked the use of these drugs to Alzheimer’s disease.
Thus, in a study led by Kevin Nead, MD, DPhil, Stanford University School of Medicine (Sanford, CA), researchers investigated the association of ADT as a treatment for prostate cancer with the subsequent development of dementia.
Overall, 9455 men diagnosed with prostate cancer between 1994 and 2013 were identified and included in the analysis. The effect of ADT on dementia risk was calculated using propensity score-matched Cox proportional hazards regression models and Kaplan-Meier survival analysis.
Among the 9272 men included in the final analysis, researchers observed a statistically significant association between use of testosterone-lowering therapeutics and risk of dementia (hazard ratio, 2.17; 95% CI, 1.58-2.99; P < .001). At 5 years, 7.9% of patients who received ADT developed dementia while only 3.5% of those not treated with ADT developed the condition.
Additional analysis also revealed that patients treated with ADT for at least 12 months had the greatest absolute increased risk of dementia while ADT users 70 years and older were the most likely to develop dementia within 5 years.
From these results, researchers concluded that ADT in the treatment of prostate cancer may increase one’s risk of dementia, though patients should not alter their treatment regimens until the findings can be verified in prospective studies.
