A new study presented at the American Society of Clinical Oncology annual meeting in Chicago has reported that cognitive function appears to improve after the completion of five years of adjuvant hormonal therapy, regardless of whether the treatment consists primarily of tamoxifen, the aromatase inhibitor Femara, or a combination of the two. Endocrine therapy for breast cancer has been reported to affect mental acuity, short-term memory, decision-making, and other types of cognitive functioning.

The study included 96 women participating in the Breast International Group 1-98 trial. In this trial, postmenopausal women with early-stage, hormone receptor positive breast cancer received either tamoxifen for five years, letrozole (Femara) for five years, tamoxifen for two years followed by letrozole for three years, or letrozole for two years followed by tamoxifen for three years.

Cognitive function (speed of psychomotor function, visual attention, working and verbal memory, learning) was evaluated using computerized tests during the fifth year of treatment and one year after treatment completion. Scores for each test and time point were standardized according to age-specific norms. A significant improvement in the change in composite score from year five to year six was found for all of the study participants. The improvement was significant for each of the performance tasks measured, and within all of the groups (tamoxifen, letrozole, and switch). The difference in the change in composite score between treatments was comparable, with no group experiencing superior improvement compared to the other groups. The authors conclude that among postmenopausal breast cancer patients who receive either adjuvant letrozole or tamoxifen, cognitive function appears to improve one year after end of treatment and that this change does not differ according to type of hormonal treatment.