A study published in the Journal of Clinical Oncology is negating previous studies that suggested a possible link between use of androgen deprivation therapy (ADT) for prostate cancer and Alzheimer’s disease (AD). This study included almost 31,000 men whose prostate cancer had not spread but were using (ADT).
ADT is a form of chemical castration prescribed to eliminate testosterone in men with advanced prostate cancer because the disease is fueled by testosterone. It is widely used and so effective at halting the progress of the cancer that men are often treated with ADT for many years.
Cognitive impairment is a known side effect of declining testosterone so it makes sense to have a natural concern of using ADT in men. The notion that ADT use was possibly linked with AD was that testosterone levels are traditionally lower in men with AD compared with control groups, suggesting there was maybe a connection between lowering testosterone and an increased risk for AD. Previous studies that had explored this connection found that a low testosterone level caused by ADT was associated with a higher probability of developing AD. But these studies often cover a shorter period of time – for a year or less – and it is doubtful that men were on ADT long enough to cause AD.
This new study is a large-scale population based study that looked at ADT’s effect over a four year period. If there was any man diagnosed with AD within the first year, it was not counted. Half of the men took ADT as their initial treatment while the other half did not. During a mean follow up of 4.3 years, 799 patients were diagnosed with dementia. But researchers did not find an increased risk of AD among the ADT users compared with those who did not take the therapy.
The first author, Farzin Khosrow-Khavar, stated, “For most every medication there is a judgement to be made between its intended purpose and possible adverse effects.”
The researchers noted that more studies are needed, but men with prostate cancer can be less concerned about dementia risk if they use or need ADT.
It is strongly advisable for any man diagnosed with prostate cancer and is considering the use of ADT to treat it, to discuss thoroughly with his physician on their opinion whether to use ADT or not. Factors to perhaps consider would be if there is a strong background of AD within his family, particularly among first-degree relatives of a man, such as his parents or siblings who had dementia.