Men who undergo a common treatment for prostate cancer may be at increased risk of dementia, according to a new study.
Their previous studies have shown men who undergo androgen deprivation therapy (ADT) - a testosterone-lowering therapy - may be at an increased risk of dementia, including Alzheimer's disease, compared to men who were not treated with the therapy.
This new analysis - the largest of its kind ever performed on this topic - shows that all existing studies taken together support the link to dementia and show a possible link to Alzheimer's.
"Since publishing our initial findings, there has been a lot of other research on this topic, and we wanted to see what that research was saying," said Kevin Nead, from the University of Pennsylvania in the US.
"This analysis tells us that the composite message of existing studies is that androgen deprivation therapy is associated with dementia," said Nead.
The team compiled data from four different global databases looking at studies on ADT patients and dementia and Alzheimer's. An analysis of more than 50,000 patients worldwide showed a consistent statistical link between men who underwent ADT for prostate cancer and men who developed dementia.
The numbers show correlation, not causation at this point, but that there is evidence of a direct connection, Nead said. "Research shows androgens play a key role in neuron maintenance and growth, so the longer you undergo this therapy to decrease androgens, the more it may impact the brain's normal functions," he said.
The analysis was less conclusive on the question of Alzheimer's. While there was still a connection, it was not as clearly defined as the link to dementia.
Evidence for a link between ADT and neurocognitive dysfunction is growing and should be part of the conversation between doctors and patients, Nead said.
"There's enough evidence of these links that patients should know about them when considering their options," he said.
The findings were published in the journal Prostate Cancer and Prostatic Diseases.
