The study, “Androgen Deprivation Therapy and the Risk of Dementia in Patients With Prostate Cancer,” took issue with findings in three prior observational studies reporting a link between ADT and an increased risk of dementia and Alzheimer’s disease. The researchers also noted these earlier studies had “conflicting findings.”
Prostate cancer cells usually require androgen hormones, such as testosterone, to grow. For this reason, androgen deprivation therapies, which reduce the levels of androgen hormones or their ability to bind to their specific receptors, are a mainstay treatment of patients with advanced prostate cancer and are increasingly being used in patients with localized disease.
Although ADT has been shown to delay prostate cancer progression, this therapy has also been linked with several adverse events, including diabetes, cardiovascular disease, and, possibly, cognitive impairment.
But many men with prostate cancer represent an older population, people already thought to be at an increased risk of cognitive impairment and dementia. So it is important to assess whether ADT use itself may cause increased incidence of dementia.
Researchers, led by Farzin Khosrow-Khavar, PhD, with the McGill University in Hamilton, Canada, used data from the United Kingdom’s Clinical Practice Research Datalink (CPRD), the world’s largest primary care database. They identified 30,903 men, age 40 or older, who were newly diagnosed with prostate cancer between January 1988 and April 2015. The men were followed until April 2016. To account for delays associated with dementia diagnosis and to lessen reverse causality, ADT exposure was lagged by one year.
During a mean follow-up of 4.3 years, 799 patients were diagnosed with dementia. The use of the therapy was not associated with an increased risk of dementia, when compared to patients who did not use ADT treatment. Similar findings — no association with an increased dementia risk — were observed in secondary analyses that assessed risk by type of ADT used and by the cumulative duration of ADT use.
“The findings of this large population-based study indicate that the use of ADT is not associated with an increased risk of dementia either overall, by duration of use, or by type. Additional studies in different settings are needed to confirm our findings,” the researchers wrote.