Researchers have found an association between androgen deprivation therapy (ADT) for prostate cancer and increased risk for Alzheimer’s disease, according to a recent study in the Journal of Clinical Oncology.
This risk increased for men who were on ADT for longer periods, the researchers reported. Their team included scientists from the Perelman School of Medicine at the University of Pennsylvania and the Stanford School of Medicine.
Androgens, such as testosterone and dihydrotestosterone (DHT), can fuel the growth of prostate cancer cells. Androgen deprivation therapy aims to slow down this growth by preventing androgens from working properly or reducing androgen levels altogether.
Androgen deprivation therapy may be achieved through use of regularly administered medications or through surgical removal of the testicles. Both of these methods reduce testosterone levels significantly and have impacts on various systems throughout the body.
The researchers looked at electronic medical data from 16,888 men with prostate cancer. The data came from the Stanford health system and Mt. Sinai Hospital in New York City. Overall, 14% of the men underwent ADT and were followed for a median of 2.7 years.
The team found that the men on ADT had higher rates of Alzheimer’s diagnoses during the follow-up period, compared to men who did not receive ADT. In fact, men on ADT were about 88% more likely to develop Alzheimer’s.
They also discovered that risk for Alzheimer’s increased with the length of time on ADT.
The reasons for the link are unclear. However, some studies have shown that low testosterone may leave brain cells more susceptible to dementia and spur the production of amyloid beta, a protein linked to Alzheimer’s.
Also, some conditions associated with low testosterone, including diabetes and atherosclerosis, may increase the risk of Alzheimer’s disease.
More research is needed to explore the link further.
“It’s hard to determine the precise amount of increased risk in just one study and important to note that this study does not prove causation,” said lead author Kevin T. Nead, MD, MPhil, a resident at the Perelman School of Medicine, in a news release.
“But considering the already-high prevalence of Alzheimer’s disease in older men, any increased risk would have significant public health implications,” he added.
American Cancer Society
“Hormone (androgen deprivation) therapy for prostate cancer”
(Last revised: March 12, 2015)
Journal of Clinical Oncology
Nead, Kevin T., et al.
“Androgen Deprivation Therapy and Future Alzheimer’s Disease Risk”
(Abstract. Published online before print: December 7, 2015)
University of Pennsylvania Health System/Perelman School of Medicine
“Testosterone-Lowering Therapy for Prostate Cancer May Increase Alzheimer's Risk”
(News release. December 7, 2015)