Men treated with testosterone-lowering drugs for their prostate cancer are more than twice as likely to develop dementia as those not receiving such treatment, according to a study that reviewed the medical records of nearly 10,000 patients.
Researchers behind the study, “Association Between Androgen Deprivation Therapy and Risk of Dementia,” published in the journal JAMA Oncology, however, cautioned that patients should not change their treatment without discussing it with their physician.
Last year, the research team at Stanford University School of Medicine discovered that testosterone-lowering treatment was linked to a higher risk of developing Alzheimer’s disease. Since Alzheimer’s is commonly confused with vascular dementia, the team decided to explore if the association held true when including all types of dementia.
They identified medical records of 9,272 men with prostate cancer who had been treated between 1994 and 2003, of which 1,829 received testosterone-lowering treatment. To make sure results became as robust as possible, they first removed all patients who had dementia at prostate cancer diagnosis. Then, they matched treated and untreated patients with the same disease stages, to make sure the comparisons were valid.
The team discovered that within five years, 7.9 percent of those receiving testosterone-targeting treatment had developed dementia. Among patients not receiving such treatment, the number was 3.5 percent.
“The risk is real and, depending on the prior dementia history of the patient, we may want to consider alternative treatment, particularly in light of a recent prospective study from the U.K.,” Nigam Shah, MBBS, PhD, associate professor of biomedical informatics research at Stanford, and senior author of the study, said in a press release.
The study to which the researchers are referring showed that prostate cancer patients had the same chances of survival within a 10-year time frame, whether they received aggressive treatment or active monitoring. Only 1% of men died during the 10 years, suggesting that monitoring may be as good as treatment, without causing side effects.
Based on the findings, researchers argue it makes sense to identify those at risk for dementia before considering testosterone-lowering treatment.
Researchers, however, underscored that the data are derived from medical records, and that prospective clinical trials ultimately are needed to remove any doubts that testosterone-lowering treatments may trigger cognitive decline.