Androgen Deprivation Therapy Linked to Increased Alzheimer's Disease Risk in Patients with Prostate Cancer

Patients taking testosterone-lowering therapy for prostate cancer are at increased risk for Alzheimer’s disease, according to findings published in the Dec. 7 issue of the Journal of Clinical Oncology.

 

Researchers from Stanford University Medical Center and Penn Medicine studied 16,888 individuals with prostate cancer in order to test the association of androgen deprivation therapy (ADT) in the treatment of these patients with subsequent Alzheimer’s disease risk. About 15 percent of the patients met the inclusion criteria and were receiving ADT during a median follow up period of about 3 years – almost 2,400 patients.

 

“This is the kind of question that typically you would need a large clinical trial to answer,” senior author Nigam Shah, MBBS, PhD, associate professor of biomedical informatics research at Stanford, explained in a press release. A study like that would be enormously expensive. “So instead, we're making secondary use of existing clinical data collected as part of routine medical care.”

 

The researchers noted that testosterone may promote the growth of prostate tumors in patients, and so by using ADT, the prostate cancer growth is halted. This technology has been in use since the 1940s.

 

The patients treated with ADT had nearly a twofold increased (1.88 times) rate of being diagnosed with Alzheimer’s disease in the follow up period, compared to prostate cancer patients who did not receive ADT, the researchers found. For men treated with ADT for longer than 12 months, the risk for Alzheimer’s disease was 2.12 times more likely.

 

“Broader dementias and vascular dementia are kind of hard to quantify and define, so we had to narrow the scope of the analysis to make it feasible with the methods that we have available,” Shah said, commenting that ADT also sometimes increases cognitive deficiencies and hand/ eye coordination for reasons outside of Alzheimer’s disease. The team chose to focus directly on Alzheimer’s because it can be easily identified among medical records.

 

“The association found in this study should be evaluated in the context of the overall treatment choices available to any specific patient,” Shah said, highlighting that physicians should discuss potential risks for Alzheimer’s with ADT patients. “This study demonstrates the value of using existing electronic medical record data to quantify the trade-offs that various treatments offer.”

 

Using the same data from an original study would take 12 to 18 months, Shah concluded. By using existing data, the investigators saved time, money and resources spent on approval periods.

 

“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,” lead author Kevin T. Nead concluded in another statement. “But considering the already-high prevalence of Alzheimer’s disease in older men, any increased risk would have significant public health implications.”