STANFORD, Calif., Dec. 9 (UPI) -- Androgen deprivation therapy, or ADT, is one of the primary methods of treating prostate cancer because of the role testosterone plays in tumor growth. New research shows the treatment also doubles the risk for a diagnosis of Alzheimer's disease.
ADT has been used used to lower testosterone and other androgens in cancer patients since the 1940s and about 500,000 men in the United States are currently being treated with it.
Previous research has shown lower levels of testosterone can increase the risk for cognitive impairment and the development of Alzheimer's disease, leading researchers to call the new study's findings an association rather than saying the treatment causes Alzheimer's.
"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," Dr. Kevin Nead, a resident in the radiation oncology department in the Perelmen School of Medicine at the University of Pennsylvania, said in a press release. "But considering the already-high prevalence of Alzheimer's disease in older men, any increased risk would have significant public health implications."
Researchers at the University of Pennsylvania and Stanford University looked at medical records for 16,888 prostate cancer patients treated in the Stanford health system and at Mt. Sinai Hospital in New York. Of these, 2,397 patients had been treated with ADT. The researchers matched them with a control group of non-ADT patients.
Patients treated with ADT were 1.88 times as likely to receive an Alzheimer's disease diagnosis over a median of 2.7 years after the conclusion of treatment. A subset of men treated with ADT for longer than 12 months were 2.12 times as likely as patients who did not receive ADT to be diagnosed with Alzheimer's.
"The association found in this study should be evaluated in the context of the overall treatment choices available to any specific patient," Dr. Nigam Shah, and associate professor of biomedical informatics research at Stanford University, in a press release.
The study is published in the Journal of Clinical Oncology.