Risk of dementia following androgen deprivation therapy for treatment of prostate cancer.

BACKGROUND

Evidence for androgen deprivation therapy (ADT) and risk of dementia is both limited and mixed. We aimed to assess the association between ADT and risk of dementia among men with localized and locally advanced prostate cancer (PCa).

METHODS

We conducted a retrospective cohort study using SEER-Medicare-linked data among 100,414 men aged ≥ 66 years and diagnosed with localized and locally advanced PCa (cT1-cT4) between 1992 and 2009. We excluded men with a history of stroke, dementia, or use of psychiatric services. Men were followed until death or administrative end of follow-up at 36 months. Inverse-probability weighted Fine-Gray models were used to estimate hazard ratios (HR) and 95% confidence intervals (CI) for Alzheimer's, all-cause dementia, and use of psychiatric services by duration of pharmacologic ADT (0, 1-6, and ≥ 7 months).

RESULTS

Among 100,414 men with PCa (median age 73 [IQR: 69-77] years; 84% white, 10% black), 38% (n = 37,911) received ADT within 6 months of diagnosis. Receipt of any pharmacologic ADT was associated with a 17% higher risk of all-cause dementia (HR 1.17, 95% CI 1.07-1.27), 23% higher risk of Alzheimer's (HR 1.23, 95% CI 1.11-1.37), and 10% higher risk of psychiatric services use, though the confidence interval included the null (HR 1.10, 95% CI 1.00-1.22). Longer duration of ADT (≥7 months) was associated with a 25% higher risk of all-cause dementia, 34% higher risk of Alzheimer's, and 9% higher risk of psychiatric services, compared with no ADT.

CONCLUSIONS

Our study supports an association between pharmacologic ADT and higher risk of all-cause dementia, Alzheimer's, and use of psychiatric services among men with localized and locally advanced PCa.