Subjective and objective cognitive functioning among patients with breast cancer: effects of chemotherapy and mood symptoms.

Background: Previous findings regarding declines in cognitive functioning among patients with breast cancer (BC) before and after chemotherapy have been inconsistent. The present study explored the effect of BC and cancer-related chemotherapies on cognitive functioning.

Methods: A cross-sectional design was adopted to compare BC patients before their chemotherapy treatment, BC patients 3 ~ 9 months after the completion of chemotherapy, and noncancer controls. Evaluations of cognitive functioning included subjective and objective dimensions, with focus on memory, executive functioning, attention, and language. ANCOVA and Pearson's correlation analysis were used to examine the relationship among cancer, chemotherapy, cognitive performance, and psychological distress.

Results: After adjustment for intelligence quotient, anxiety, and depression, we found significant differences in the Semantic Association of Verbal Fluency between post-chemotherapy (C/T) patients and noncancer controls. Specifically, post-C/T patients scored lower than controls (p = 0.03, η = 0.07). No significant differences were found in other objective cognitive measures. However, both subjective and objective cognitive scores were significantly associated with depression, anxiety, and fatigue. In BC patients, levels of anxiety were positively correlated with measures of executive function. Among pre-C/T patients, self-perceived interference by fatigue was positively associated with better performances in some of the objective cognitive measures.

Conclusion: Our findings suggest cognitive impairments in the domain of executive functioning among patients with BC who received chemotherapy. Providing relevant suggestions or strategies of managements for these negative consequences may help increase the long-term quality of life of patients with BC.