The cognitive effects of adjuvant chemotherapy in early stage breast cancer: a prospective study

PURPOSE: The primary purpose of this study was to evaluate the cognitive effects of adjuvant chemotherapy in post-menopausal breast cancer patients. PATIENTS AND METHODS: Breast cancer patients scheduled to receive adjuvant chemotherapy (n = 61) completed comprehensive cognitive testing before and after treatment. A control group of women receiving adjuvant hormonal therapy (n = 51) was tested at comparable intervals. RESULTS: Mean scores for both patient groups were within the normal range relative to published norms on all cognitive tests at both time points, and generally inclined or stayed the same from baseline to retest in both groups. However, in an analysis of individual change scores, the chemotherapy patients were 3.3 times more likely than the hormonal patients to show reliable cognitive decline (31 and 12%, respectively). Chemotherapy subjects showing decline were less educated and had higher baseline depression scores than their counterparts who did not decline. Working memory was the cognitive domain most vulnerable to the effects of chemotherapy. CONCLUSION: These data support previous findings of a subtle negative influence of chemotherapy on cognitive function in a subgroup of breast cancer patients. The results are discussed in terms of the importance of study design.