The effects of hormone therapy on cognition in breast cancer.

The use of hormonal therapies for the treatment of breast cancer is common, yet few studies have examined the possible cognitive effects. Several regions of the brain, important in memory and cognition, are rich in oestrogen receptors. As a result, the long-term use of anti-oestrogens may have potential consequences for cognition. This project aims to establish whether significant cognitive deficit exists in women receiving hormone therapy for breast cancer and to develop a cognitive package that is sensitive to the potential effects of oestrogen deficiency on cognition. Cognitive assessments measured a range of memory and attention functions in patient and control groups to identify whether cognitive impairment, if apparent, occurs at a widespread or function specific level. Ninety-four patients from the anastrozole, tamoxifen and combined (ATAC) trial and 35 non-cancer controls were assessed. Groups did not differ significantly in age or estimated full-scale intelligence. The patient group did not differ from controls on measures of working memory, attention and visual memory but was significantly impaired compared to the control group on measures of verbal memory (P=0.026) and processing speed (P=0.032). Cognitive performance in the patient group was not significantly related to length of time on trial or measures of psychological morbidity. As more and more hormonal agents are used in clinical trials of both adjuvant and preventive settings it is of vital importance that any potentially deleterious effects on cognitive function are measured adequately. Preliminary results from this study suggest that anti-oestrogen therapy may cause a specific deficit in verbal memory that corroborates the links between oestrogen levels and verbal memory often reported in studies of the cognitive benefits of hormone replacement therapy.