[The effect of hormone therapy on cognitive function in patients with breast cancer].

Preclinical and clinical studies suggest that oestrogens have an important role in brain functioning and cognitive ability. Given that hormone therapies for breast cancer reduce oestrogen levels or block oestrogen receptors, it is conceivable that these agents also influence cognitive function. Several small studies have been conducted to address this issue, but many of them are methodologically insufficient. The negative effects of oophorectomy and luteinising hormone-releasing hormone (LHRH) analogues on verbal memory and working memory have been demonstrated the most consistently, albeit only in small studies. Anastrozole and tamoxifen also appear to exert some negative effect on cognition, but well-designed studies are lacking. No data are available on the influence of the aromatase inhibitors exemestane and letrozole on cognitive function. Raloxifene, a drug that has no obvious advantages over tamoxifen and will likely not be developed further for breast cancer treatment, has no negative influence on cognitive functioning. It remains unclear whether the observed effects are transient or permanent, and to what extent age, menopausal status and duration of therapy influence the severity of cognitive effects.