Evidence suggests that some patients with breast cancer experience cognitive difficulties following chemotherapy. This longitudinal study was done to examine the prevalence of cognitive impairment and trajectory of cognitive function over time in women with breast cancer, who received adjuvant chemotherapy.

Participants were 137 patients with breast cancer. They completed neuropsychological tests and the Functional Assessment of Cancer Therapy-Cognitive Function before adjuvant therapy (pretest), toward the end of adjuvant therapy (posttest), and 6 months after the completion of adjuvant therapy (follow-up test). Of the patients, 91 were treated with adjuvant chemotherapy and 46 patients who did not receive chemotherapy made up the comparison group. A reliable-change index and repeated-measure ANOVA were used for statistical analyses.

At the posttest point, over 30% of patients showed complex cognitive impairment and reported greater difficulty in subjective cognitive function. At the follow-up test point, 22.0% of patients exhibited complex cognitive impairment and 30.8% of patients complained of subjective cognitive impairment. Repeated-measure ANOVA showed significant decreases after receiving chemotherapy followed by small improvements 6 months after the completion of chemotherapy in cognitive domains of change for attention and concentration, memory, executive function, and subjective cognitive function.

These results suggest that chemotherapy in patients with breast cancer may be associated with objective and subjective cognitive impairments. Further studies are needed to explore the potential risk factors and predictor of chemotherapy-related cognitive changes. Also nursing interventions for prevention and intervention of cognitive impairments should be developed and tested.