Risk of Alzheimer’s may be raised by hormone therapy for prostate cancer

Written by Sharon Salt, Editor

People with prostate cancer who are taking androgen deprivation therapy (ADT) may be at a higher risk of developing Alzheimer’s disease or dementia compared with people who do not receive the therapy.
Within the study, which has been published in JAMA, researchers analyzed the association between ADT exposure and diagnosis of Alzheimer’s disease or dementia among elderly men with prostate cancer. Of the 154,089 men sampled in the study, 62,330 received ADT within 2 years of their prostate cancer diagnosis and 91,759 did not.

It was reported that 13% of people with prostate cancer who received the hormone therapy were later diagnosed with Alzheimer’s disease, compared with 9% who did not receive ADT. These numbers widened for dementia, with 22% of individuals with prostate cancer who received ADT being diagnosed, compared with 16% who did not receive the therapy.

“To our knowledge, this is one of the largest studies to date examining this association, and it followed patients for an average of 8 years after their prostate cancer diagnosis. Our results suggest that clinicians need to raise their awareness about potential long-term cognitive effects of hormone therapy and discuss these risks with their patients,” commented Ravishankar Jayadevappa (University of Pennsylvania, PA, USA), principal investigator of the study.

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After controlling for several factors (e.g., other medical conditions, disease severity and sociodemographic characteristics) the researchers determined that people with prostate cancer who receive ADT face a hazard ratio that translates to a 14% increased risk of developing Alzheimer’s and a 20% increased risk of dementia, when compared with individuals who are not exposed to ADT.

Several recent papers have also examined the association – or lack thereof – between ADT and dementia. According to the authors of the present study, past studies relied on data from a single institution, while others failed to adjust for cancer stage, ADT dose and duration. By contrast, the current study used data from the Surveillance, Epidemiology ad End Results (SEER) Medicare-linked database of the National Cancer Institute.

The team noted that more research is necessary to understand the possible biological mechanisms that underlie the link between dementia and ADT.

Co-author Thomas Guzzo (University of Pennsylvania) concluded: “I think we need to look at these patients on an individual level. Certainly there are patients who need hormonal therapy and benefit from it greatly. There are others where the evidence is less clear, and in these patients, we should strongly consider the risk of hormonal therapy versus the benefit in treating their prostate cancer. This should be a shared decision-making process with the patient.”

Sources: Jayadevappa R, Cchatre S, Malkowicz B, Parikh RB, Guzzo T, Wein AJ. Association between androgen deprivation therapy use and diagnosis of dementia in men with prostate cancer. JAMA Netw. Open 2(7), e196562 (2019); www.pennmedicine.org/news/news-releases/2019/july/hormone-therapy-for-prostate-cancer-may-raise-risk-of-alzheimers-dementia