Androgen deprivation therapy (ADT) is a common treatment for prostate cancer, which lowers testosterone. A recent analysis has found substantial evidence linking ADT to dementia.
A previous study done by researchers at the Perelman School of Medicine at the University of Pennsylvania found that men who received ADT may be at an increased risk for dementia, including Alzheimer’s disease, compared with men who were not treated with the therapy. The absolute increased risk of developing dementia, they determined, was 4.4% at 5 years.1
Since that study was published in October 2016, researchers have looked into it further. This analysis, published in Prostate Cancer and Prostatic Diseases,2 looked at data from 4 different, global databases (PubMed, Web of Science, Embase, PsycINFO), comparing studies on ADT patients and dementia and Alzheimer’s. All the existing studies together, researchers said, support the link to dementia, and show a possible link to Alzheimer’s.
“This analysis tells us that the composite message of existing studies is that androgen deprivation therapy is associated with dementia,” according to Kevin Nead, MD, MPhil, a radiation oncology resident with the Perelman School of Medicine at the University of Pennsylvania and an author on both studies.
From the 4 databases, there were 9 studies on the outcome of dementia among patients exposed to ADT versus a lesser-exposed comparison group (eg, ADT vs no ADT or continuous ADT vs intermittent). An analysis of 50,541 patients showed an increased risk of dementia among those who had undergone ADT. Nead clarified that this analysis shows correlation, although not causation at this point.
“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,” Nead said.
A link between ADT and Alzheimer’s was found as well, but it was not as clearly defined as the link to dementia.
When the earlier study was published, Nead stated, “It would be really hard to justify not using a medication that we know extends life for a possible negative consequence that at this point is potential, probably at best, but nor proven.”
The more recent analysis suggests that the evidence between ADT and neurocognitive dysfunction continues to grow, said Nead, and should be a part of the conversations between doctors and patients: “There’s enough evidence of these links that patients should know about them when considering their options.”
Nead KT, Gaskin G, Chester C, et al. Association between androgen deprivation therapy and risk of dementia. JAMA Oncol. 2017;3(1):49-55.
Nead KT, Sinha S, Nguyen PL. Androgen deprivation therapy for prostate cancer and dementia risk: a systematic review and meta-analysis [published online before print March 28, 2017]. Prostate Cancer Prostatic Dis.