How prostate cancer treatment leads to dementiaStaff Writer | October 18, 2016
A new study suggests that men with prostate cancer who are treated with testosterone-lowering drugs are twice as likely to develop dementia within five years as prostate cancer patients whose testosterone levels are not tampered with.
Hormones Playing with hormones can be tricky
Kevin Nead, MD, DPhil, a resident at the University of Pennsylvania who got his medical degree at Stanford, is the lead author.
Nigam Shah, MBBS, PhD, associate professor of biomedical informatics research at Stanford, is the senior author.
Testosterone can promote the growth of prostate tumors, and so clinicians have used androgen deprivation therapy to lower testosterone and other androgens in prostate cancer patients since the 1940s. In the United States, about a half-million men currently receive ADT as a treatment for prostate cancer.
A 2015 study by the same authors found an association between ADT and Alzheimer's disease. In the new paper, the team expanded their work to include several other forms of dementia. "When we published our last paper, a letter to the editor pointed out that Alzheimer's is often confused with vascular dementia," said Shah.
"So instead of looking for Alzheimer's and dementia separately, we decided to aggregate them into a higher-level category - all dementias and cognitive decline." Such aggregation could minimize the question of misdiagnosis, Shah said, and increase the sample size to provide more statistical power.
The team looked at deidentified records from Stanford Medicine's clinical-research data warehouse for nearly 10,000 patients with prostate cancer.
Of the 1,829 who received androgen deprivation therapy, 7.9 percent developed dementia within five years, compared with 3.5 percent of those not treated with ADT.
"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.," said Shah. ■