Some ADT side effects are scarier than others, and near the top of the list is the risk of cognitive impairment. Is it real? Is it substantial? What is surprising is how much has been published on this topic and the fact that these questions still remain unresolved.
A new paper out of Yale University has an encouraging title, but the authors’ bottom line is that they “have not been able to conclusively establish a correlation between ADT and cognitive dysfunction.” The paper is in fact a review of what has been published previously, and not a research paper with any new data. As a review, though, it excellently reveals why we still don’t know the extent to which ADT influences cognition. The review shows that the data on this topic are all over the map, with a wide range of published findings. Indeed, some studies conclude that ADT has no impact on cognition, while others suggest that it increases the risk of dementia.
So why is there so much variation? Some studies use retrospective data extracted from large data sets. In this type of study, the researchers search for correlations between treatment with ADT and a diagnosis of some form of cognitive impairment. Due to the nature of retrospective and correlational study designs, these types of studies suffer from an inability to gather comparable data on the patients. When their results conflict, it can be because their patient populations are not the same.
The other type of studies are prospective studies. These are usually much smaller. But they too suffer from using various neurocognitive tests which the authors note “may not be optimal for detection of more subtle, but clinically relevant cognitive impairment.”
In the absence of clear evidence of ADT-related cognitive impairment, the authors wisely do not speculate on how to treat cognitive impairment in patients on ADT. But it can be pointed out that physical exercise has been shown to help improve circulation and reduce the risk of cognitive impairment from aging in general. So, once again, the case can be made that patients on ADT who wish to limit declines in brain function should stay on an exercise program that helps maintain cardiovascular fitness.
To read the study abstract, see: https://www.ncbi.nlm.nih.gov/pubmed/32048059
Kluger, J., Roy, A., & Chao, H.H. (2020). Androgen Deprivation Therapy and Cognitive Function in Prostate Cancer. Current Oncology Reports, 22(3), 24. doi: 10.1007/s11912-020-0884-1