Common treatment for prostate cancer may increase risk of Alzheimer’s, dementia

a dbf ee e cd fe thought

Prostate cancer is the most common cancer among men, excluding skin cancers. It is, as a generalization, a slow process, and treatment include surgery, radiation, and chemotherapies. Prostate treatment ads promoting radiation therapy over surgical intervention can be heard throughout the day on radio and television. The cancer is driven, in part, by testosterone so that androgen deprivation therapy (ADT) is often used in conjunction with surgery or radiation to slow cancer progression and mortality. A new study looks at one specific unintended consequence of ADT, dementia.

The study was a retrospective review of SEER, the Surveillance, Epidemiology, and End Results dataset of the National Cancer Institute, which covers about a quarter of our nations Medicare beneficiaries. The men, were over 66, with localized or advanced prostate cancer who were followed for ten years. The usual demographics were collected as well as specific information on the severity of prostate cancer. ADT is most frequently given as an injection every three months, and the number of doses was noted in the dataset. Finally, the outcomes were a diagnosis of Alzheimer’s or dementia subsequent to the diagnosis of prostate cancer. Roughly 60,000 men had been given ADT, 90,000 had not. Men receiving ADT tended to have more aggressive forms of prostate cancer, were slightly older, with more co-morbidities and had undergone less surgical intervention.

  • Patients receiving ADT had a greater incidence of both dementia and Alzheimers.
  • The risk of developing Alzheimer’s was 20% greater in those men receiving ADT.
  • The risk of developing dementia was 14% greater in that same cohort.
  • There did appear to be a dose-dependency with the risk for both conditions rising to a peak at 4 to 8 cycles of ADT and then leveling off.
  • Only men with no co-morbidities “showed an association between exposure to ADT and diagnosis of Alzheimer disease … or dementia.”
  • Patients undergoing synchronous surgery had a lower risk, while the risk increased for those patients undergoing radiation or chemotherapy.

The researchers concluded

“While our study suggests an association between ADT and subsequent dementia diagnosis, we were unable to further investigate possible biological mechanisms of this association. It is important to note that dementia may have a latency period of 1 decade or more prior to cognitive manifestations,… Hence, it is possible that ADT has a modifying or augmenting, rather than de novo, effect on development of dementia.”

No physician would prescribe this therapy “to be safe” — you can see that as the patients treated with ADT had more aggressive and advanced cancers, less amenable to surgery. But it demonstrates how “do no harm” is far more complicated than we had anticipated. For this cancer, as with nearly all diseases, there is no magic bullet, every treatment has a cost and benefit. For those that like numbers; on the risk side, the number of patients you must treat to cause harm (dementia or Alzheimers) in one individual is 18, on the benefit side, the number of patients you must treat to save one life at ten years is roughly 46. [1] Put in other terms, for every life you save, two others will develop Alzheimers or dementia. Tough call. While economists can calculate quality years of life, patients will have the choice between the cancer they have and the dementia they may get. My bet is that cancer in the here and now is a higher priority than possible dementia in the future.

Related article:  Viewpoint: 'Heavy' pesticide exposure linked to cardiovascular disease? Flawed study raises 'troubling' questions about public health research

[1] The numbers needed to treat or NNT for prostate cancer does not separate those treated with any specific modality, so at best is a very rough measure.

Dr. Charles Dinerstein, M.D., MBA, FACS is Senior Medical Fellow at the American Council on Science and Health. He has over 25 years of experience as a vascular surgeon. He completed his MBA with distinction in the George Washington University Healthcare MBA program and has served as a consultant to hospitals. While no longer clinically active, he has had his writing featured at KevinMD and Doximity. Follow him on Twitter @CRDtoday

This article originally ran at the American Council on Science and Health’s website as A New Controversy over Prostate Cancer’s Treatment and has been republished here with permission.

Outbreak Daily Digest
Biotech Facts & Fallacies
Talking Biotech
Genetics Unzipped
Video: Test everyone – Slovakia goes its own way to control COVID

Video: Test everyone – Slovakia goes its own way to control COVID

As Europe sees record coronavirus cases and deaths, Slovakia is testing its entire adult population. WSJ's Drew Hinshaw explains how ...
mag insects image superjumbo v

Disaster interrupted: Which farming system better preserves insect populations: Organic or conventional?

A three-year run of fragmentary Armageddon-like studies had primed the journalism pumps and settled the media framing about the future ...
dead bee desolate city

Are we facing an ‘Insect Apocalypse’ caused by ‘intensive, industrial’ farming and agricultural chemicals? The media say yes; Science says ‘no’

The media call it the “Insect Apocalypse”. In the past three years, the phrase has become an accepted truth of ...
globalmethanebudget globalcarbonproject cropped x

Infographic: Cows cause climate change? Agriculture scientist says ‘belching bovines’ get too much blame

A recent interview by Caroline Stocks, a UK journalist who writes about food, agriculture and the environment, of air quality ...
organic hillside sweet corn x

Organic v conventional using GMOs: Which is the more sustainable farming?

Many consumers spend more for organic food to avoid genetically modified products in part because they believe that “industrial agriculture” ...
benjamin franklin x

Are most GMO safety studies funded by industry?

The assertion that biotech companies do the research and the government just signs off on it is false ...

Environmental Working Group: EWG challenges safety of GMOs, food pesticide residues

Known by some as the "Environmental Worrying Group," EWG lobbies for tighter GMO legislation and famously puts out annual "dirty dozen" list of fruits and ...
m hansen

Michael Hansen: Architect of Consumers Union ongoing anti-GMO campaign

Michael K. Hansen (born 1956) is thought by critics to be the prime mover behind the ongoing campaign against agricultural biotechnology at Consumer Reports. He is an ...
News on human & agricultural genetics and biotechnology delivered to your inbox.
Optional. Mail on special occasions.
Send this to a friend