Purpose: Use of androgen deprivation therapy may increase the risk of cognitive impairment in men with prostate cancer. We performed a systematic review of the risk of overall cognitive impairment as an outcome in men receiving androgen deprivation therapy for prostate cancer.

Materials and methods: Studies were identified through PubMed®, MEDLINE®, PsycINFO®, Cochrane Library and Web of Knowledge/Science™. Articles were included if they 1) were published in English, 2) had subjects treated for prostate cancer with androgen deprivation therapy, 3) incorporated longitudinal comparisons and 4) used control groups. In addition, prospective studies were required to assess an established cognitive related end point using International Cognition and Cancer Task Force criteria defining impaired cognitive performance as scoring 1.5 or more standard deviations below published norms on 2 or more tests, or scoring 2.0 or more standard deviations below published norms on at least 1 test. The effect of androgen deprivation therapy on cognitive impairment was pooled using a random effects model.

Results: Of 221 abstracts 26 were selected for full text review, and 2 prospective and 4 retrospective studies were analyzed. Androgen deprivation therapy was not associated with overall cognitive impairment when the prospective cohort studies were pooled (OR 1.57, 95% CI 0.50 to 4.92, p = 0.44) with significant heterogeneity between estimates (I² = 83%). In retrospective data the relative risk of any cognitive impairment, including senile dementia and Alzheimer disease, was increased in men receiving androgen deprivation therapy, although the difference was not statistically significant (HR 1.28, 95% CI 0.93 to 1.76, p = 0.13) with moderate heterogeneity between estimates (I² = 67%).

Conclusions: Analyses between overall cognitive impairment and use of androgen deprivation therapy defined according to International Cognition and Cancer Task Force criteria in a pooled analysis were inconclusive. In retrospective cohort studies the risk of overall cognitive impairment after androgen deprivation therapy was not significant. Better prospective studies need to be designed for the assessment of this end point.