Purpose: Prior research examining the impact of androgen deprivation therapy (ADT) for prostate cancer on cognitive performance has found inconsistent relationships. The purpose of this study was to systematically review the existing literature and determine the effect of ADT on performance across seven cognitive domains using meta-analysis.
Methods: A search of PubMed Medline, PsycINFO, Cochrane Library, and Web of Knowledge/Science databases yielded 157 unique abstracts reviewed by independent pairs of raters. Fourteen studies with a total of 417 patients treated with ADT were included in the meta-analysis. Objective neuropsychological tests were categorized into seven cognitive domains: attention/working memory, executive functioning, language, verbal memory, visual memory, visuomotor ability, and visuospatial ability.
Results: Separate effect sizes were calculated for each cognitive domain using pairwise comparisons of patients who received ADT with (1) prostate cancer patient controls, (2) noncancer controls, or (3) ADT patients' own pre-ADT baselines. Patients treated with ADT performed worse than controls or their own baseline on visuomotor tasks (g = -0.67, p = .008; n = 193). The magnitude of the deficits was larger in studies with a shorter time to follow-up (p = .04). No significant effect sizes were observed for the other six cognitive domains (p = .08-.98).
Conclusions: Prostate cancer patients who received ADT performed significantly worse on visuomotor tasks compared to noncancer control groups. These findings are consistent with the known effects of testosterone on cognitive functioning in healthy men. Knowledge of the cognitive effects of ADT may help patients and providers better understand the impact of ADT on quality of life.