Cognitive effects of chemotherapy in post‐menopausal breast cancer patients 1 year after treatment

Abstract

Studies in breast cancer patients indicate that chemotherapy may cause subtle cognitive disturbances in some women, but the course is unclear. The current study evaluated the cognitive effects of adjuvant chemotherapy in post-menopausal breast cancer patients 1 year following completion of treatment. Breast cancer patients scheduled to receive adjuvant chemotherapy (n=53) completed comprehensive neuropsychological testing before commencing chemotherapy (T1), 1 month after completing chemotherapy (T2), and again 1 year later (T3). A control group of women receiving adjuvant hormonal therapy (n=40) was tested at comparable intervals. A standardized regression-based approach was used to identify cognitive decline, and incidence of decline was compared across treatment groups. Whereas at T2, chemotherapy patients were more likely to show cognitive decline than hormonal patients, by T3, the frequency of reliable cognitive decline was the same in both groups (11 and 10%, respectively). However, those chemotherapy patients receiving hormonal therapy at T3 were inferior to the chemotherapy patients not receiving hormonal treatment on composite measures of processing speed and verbal memory. These data suggest that there is a subtle negative impact of chemotherapy on cognitive function in breast cancer patients shortly following completion of treatment, but that this resolves within 1 year. However, given that our control group comprises breast cancer patients receiving hormonal therapy, and indications that hormonal therapy may also adversely affect cognition, such conclusions must be considered tentative.