Effects of long-term androgen deprivation therapy on cognitive function over 36 months in men with prostate cancer

Many men with prostate cancer (PC) require long-term androgen deprivation therapy (ADT), but to the authors' knowledge, its effects on cognitive function beyond 1 year are not described.

Three groups of men aged ≥50 years who were matched based on age and education were enrolled: 77 patients with nonmetastatic PC who initiated continuous ADT, 82 patients with PC who were not receiving ADT (PC controls), and 82 healthy controls. A battery of 14 neuropsychological tests, examining 8 cognitive domains, was administered on 5 occasions over 36 months. Changes in cognitive scores over time were analyzed using 3 approaches: linear mixed effects regression, the percentage of participants per group with declines in ≥1/2 cognitive tests, and a global summary of cognitive change.

The mean age of the study subjects was 68.9 years, with a median of 16 years of education. In mixed effects models adjusted for age and education, ADT use was not found to be associated with significant changes over time in any cognitive test compared with healthy controls. The percentage of participants declining by ≥1.5 standard deviations in ≥2 tests or ≥2 standard deviations in ≥1 tests was similar across groups. A global summary of cognitive change found no statistically significant worsening of cognitive function among ADT users compared with controls. Sensitivity analyses adjusting for duration of ADT and using multiple imputation for missing data did not materially alter the study findings.

The ongoing use of ADT for up to 36 months does not appear to be associated with cognitive decline. Cancer 2016. © 2016 American Cancer Society.

Cancer. 2016 Sep 01 [Epub ahead of print]

Shabbir M H Alibhai, Narhari Timilshina, Sarah Duff-Canning, Henriette Breunis, Ian F Tannock, Gary Naglie, Neil E Fleshner, Murray D Krahn, Padraig Warde, Shireen Marzouk, George A Tomlinson

Department of Medicine, University Health Network, University of Toronto, Toronto, Ontario, Canada., Krembil Neuroscience Program, Division of Neurology, University Health Network, University of Toronto, Toronto, Ontario, Canada., Department of Medicine, University of Toronto, Toronto, Ontario, Canada., Department of Surgery, University of Toronto, Toronto, Ontario, Canada., Department of Radiation Oncology, University of Toronto, Toronto, Ontario, Canada.