Androgen deprivation therapy did not appear to increase risk for dementia, vascular dementia or Alzheimer disease among veterans with nonmetastatic prostate cancer, according to an observational cohort study published in JAMA Oncology.
“There is conflicting evidence on the association of ADT and dementia. [However,] these results may mitigate concerns regarding the long-term risks of ADT on cognitive health in the treatment of prostate cancer,” Rishi Deka, PhD, researcher in the department of radiation medicine and applied sciences at University of California San Diego School of Medicine, and colleagues wrote.
Deka and colleagues sought to assess the association between ADT and the development of any form of dementia in 45,218 men treated for nonmetastatic prostate cancer in a relatively homogeneous fashion with definitive radiotherapy with or without ADT. The men were diagnosed at the U.S. Department of Veterans Affairs from Jan. 1, 2001, to Oct. 31, 2015.
Researchers excluded men who had a prior diagnosis of mild cognitive impairment, stroke and dementia; who initiated treatment more than 1 year after a diagnosis of metastatic disease; or who received chemotherapy as a component of treatment.
New development of any form of dementia served as the primary endpoint. Vascular dementia and Alzheimer disease served as secondary endpoints.
The investigators theorized there would be no statistically significant association between the use of ADT and subsequent dementia in men with prostate cancer who received definitive radiotherapy after controlling for multiple sources of selection bias.
Median follow-up was 6.8 years (interquartile range, 4.1-9.9).
During the follow-up period, 1,497 men were diagnosed with dementia. This included 335 men diagnosed with vascular dementia, 404 with Alzheimer disease, and 758 with other or unclassified dementia.
However, investigators observed no statistically significant association between the use of ADT and any dementia (subdistribution hazard ratio [SHR] = 1.04; 95% CI, 0.94-1.16), vascular dementia (SHR = 1.2; 95% CI, 0.97-1.5), or Alzheimer disease (SHR = 1.11; 95% CI, 0.91-1.36).
Additionally, investigators observed no association between dementia and 1 year or less of ADT (SHR = 1.01; 95% CI, 0.89-1.15) or more than 1 year of ADT (SHR = 1.08; 95% CI, 0.95-1.24).
Results of a sensitivity analysis using time-varying ADT exposure showed no significant association between ADT and any dementia (SHR = 1.04; 95% CI, 0.94-1.16), vascular dementia (SHR = 1.21; 95% CI, 0.97-1.5) and Alzheimer disease (SHR = 1.11; 95% CI, 0.91-1.35).
Deka and colleagues acknowledged study limitations.
“First, because our cohort focused on radiotherapy-treated patients, the results of this study may not be generalizable to other patients with prostate cancer treated with other modalities,” Deka and colleagues wrote. “Second, our cohort included only veterans. Therefore, some differences in sociodemographic factors may exist that limit the generalizability of these results to the larger population of men with prostate cancer.” – by Jennifer Southall
Disclosures: The authors report no relevant financial disclosures.