1438P Effects of tamoxifen on cognitive functions in premenopausal patients with breast cancer: A cross-sectional study

Abstract

Cognitive side-effects of selective estrogen receptor modulators is a topic of great interest, but the phenomenon has remained less understood. Estrogen receptors are found with significant density in brain regions associated with cognition (e.g., prefrontal cortex, hippocampus), and the benefits of estrogen on cognition are well known. Whether tamoxifen acts as an antiestrogen or estrogen agonist is tissue-specific. It has mainly been studied in peripheral tissues, not in the brain, so less is known about the effect of tamoxifen on cognitive domains.We aimed to investigate the effects of tamoxifen on domain-specific cognitive functions in a cross-sectional study. We assigned 45 premenopausal women who were operated on with hormone receptor-positive early breast cancer and treated with tamoxifen and GnRh-antagonist. Neuropsychological assessment contained measurement of complex working memory (Counting Span Test), executive functions (Berg’s Card Sorting Test, Go-No Go Task, Verbal Fluency Tasks), visuo-spatial memory (Corsi block-tapping test), verbal learning and memory (Rey Auditory Verbal Learning Test; RAVLT) and implicit learning (Alternating Serial Reaction Time Task ASRT). We measured also anxiety (STAI), depression (Beck) and perceived/subjective cognitive function (FACT-Cog). Data were compared to an age- and educational- level matched healthy control group (45 premenopausal women). Mann-Whitney U-test and repeated measures ANOVA were used for statistical analysis. Here, we show that the premenopausal treated group had a higher performance than the healthy controls on the shifting component of the executive function task (Berg’s Card Sorting Test). There were no difference between groups' performance on complex working memory, visuo-spatial memory, verbal learning and memory task, and both of groups showed evidence of implicit learning. Groups did not differ from each other in anxiety, depression and perceived/subjective cognitive function. Our findings suggest that tamoxifen affects specifically cognitive functions such as set-shifting related to dorsolateral prefrontal cortex and anterior cingulate cortex.