Androgen deprivation therapy (ADT) is a mainstay of prostate cancer treatment, but it could double the risk of Alzheimer’s disease in the long term, according to research published in the Journal of Clinical Oncology
on 7 December 2015.
ADT is used to lower androgen levels in patients with metastatic prostate cancer or in combination with radiation therapy in high-risk patients, as testosterone can promote the growth of prostate tumours.
While the testosterone levels return to normal after treatment in most patients, they can remain suppressed in 20–30% of individuals. Low testosterone has been linked with cardiovascular disease and diabetes, and problems with memory, hand-eye coordination and executive functioning, which are all features of Alzheimer’s disease.
Researchers from the Stanford University School of Medicine, and Perelman School of Medicine at University of Pennsylvania used an informatics approach to see if they could find a link between ADT in prostate cancer and the development of Alzheimer’s disease.
They analysed electronic medical records from than five million patients and found 16,888 patients with prostate cancer, including 2,397 who had received ADT. Of these, 125 were newly diagnosed with Alzheimer’s disease during a median follow-up period of 2.7 years, equivalent to around a 1.88-fold increased rate compared with prostate cancer patients who did not receive ADT. The risk was 2.12-fold higher with ADT of more than 12 months’ duration.
“Our results support an association between the use of ADT in the treatment of prostate cancer and an increased risk of Alzheimer’s disease in a general population cohort,” the researchers write.
The link between ADT and Alzheimer’s disease may be because of increased levels of circulating Î² amyloid protein, the main component of the amyloid plaques seen in patients with Alzheimer’s disease, according to the researchers. This was a retrospective study, and further prospective studies will be needed to confirm the findings.
“This study is part of an active area of research into the role that sex hormones like testosterone could be playing in dementia,” says Simon Ridley, director of research at Alzheimer’s Research UK.
“Studies like this, which take advantage of the rich data held in medical records to identify potential risk factors for a particular disease, can be very useful for highlighting areas for further research. While these results suggest a possible link between androgen deprivation therapy and an increased risk of Alzheimer’s, they do not show that ADT is causing this increased risk.”
He adds: “Continued research will be important to shed light on possible reasons for this link and to help doctors better understand the benefits and potential risks of this form of treatment.”
The informatics approach could also have potential in other therapeutic areas to find links between treatment and outcomes using real world data and to generate practice-based evidence.