Many men who are treated for prostate cancer receive androgen deprivation therapy, or ADT, as part of their treatment. ADT can decrease the risk of cancer progression and death. But the therapy, which is designed to block testosterone and other hormones that may fuel the growth of cancer cells, may increase the risk of Alzheimer’s disease down the road, a new study found.
For the study, published in JAMA Network Open, researchers looked at Medicare claims of nearly 155,000 older men who had been diagnosed with prostate cancer between 1996 and 2003. Their average age was 74.
About 40 percent of the men received androgen deprivation therapy as part of their cancer treatment within two years of their diagnosis. The men had cancer of varying degrees of severity. The ADT had been given alone or in combination with chemotherapy, radiation or other cancer treatments.
The researchers followed the men over the next eight to 10 years. They found that those men who had received one to four doses of ADT were 19 percent more likely than those who hadn’t been given the hormone to be diagnosed with Alzheimer’s disease or other forms of dementia.
The risk increased in parallel with the number of doses of hormone therapy the men got. Among those who had gotten five to eight doses of ADT, the risk of Alzheimer’s increased by 28 percent, and the increased risk of all forms of dementia increased by 24 percent.
The researchers considered various factors that might increase dementia risk, including socioeconomic status, age, race, severity of cancer and other illnesses. The increased risk for Alzheimer’s disease persisted after taking into account these other factors.
Prostate cancer is the most common form of cancer among American men, after skin cancer. So, when diagnosed with prostate cancer, the decision whether to go with hormone therapy affects many men.
ADT can be lifesaving for men with prostate cancer, so it should not be dismissed because of concerns about dementia. Hormone therapy can also have long-term negative effects on bones, sexual function and cardiovascular health.
But benefits of ADT should be weighed with risks. Those with earlier-stage prostate cancer, for example, might benefit from avoiding hormone therapy if it is unlikely their disease will progress quickly.
“Our results suggest that clinicians need to carefully weigh the long-term risks and benefits of exposure to ADT in patients with a prolonged life expectancy and stratify patients based on dementia risk prior to ADT initiation,” the authors concluded.
By ALZinfo.org, The Alzheimer’s Information Site.
Reviewed by Marc Flajolet, Ph.D., Fisher Center for Alzheimer’s Research Foundation at The Rockefeller University.
Source: Ravishankar Jayadevappa, PhD; Sumedha Chhatre, PhD; Bruce Malkowicz, MD; et al: “Association Between Androgen Deprivation Therapy Use and Diagnosisn of Dementia in Men With Prostate Cancer.” JAMA Network Open, Vol 2, July 2019