Cognitive Impairment in a Subset of Breast Cancer Patients After Systemic Therapy Results From a Longitudinal Study

Context
Studies indicate adverse effects of breast cancer (BC) and cancer treatment on cognitive function.

Objectives
To investigate the effects of systemic treatment on cognitive performance in BC patients.

Methods
Participants were BC patients scheduled to receive systemic treatment (BC + SYST; n = 31), or no systemic treatment (BC; n = 24) and no-cancer (NC) controls (n = 33). Neuropsychological examinations were used to study cognitive performance on 18 tests grouped into eight cognitive domains, before adjuvant treatment (T1) and six months after chemotherapy (T2), or at similar intervals. We also assessed health-related quality of life, anxiety and depression, mood, stress, and cognitive problems. Analysis of variance was used to assess group differences of cognitive performance and multivariate normative comparison to classify impairment, comparing scores of each participant against the distribution of the scores of NC controls.

Results
Of BC + SYST, 16% were cognitively impaired at T2, compared to 4% in BC and 6% in NC. Although not significant, we observed moderate effect sizes for worse performance in the BC + SYST group compared to NC (Flanker congruent [effect size {ES} = 0.44] and stimulus incongruent [ES = 0.44]) and compared to BC (Controlled Oral Word Association Test [ES = 0.47], digit span [ES = 0.41], and Hopkins Verbal Learning Test immediate [ES = 0.71] and delayed recall [ES = 0.65]). Cognitively impaired patients had a significantly lower estimated premorbid intelligence, worse physical and social functioning, and more distress at T2 compared to unimpaired patients.

Conclusion
Our findings indicate that cognitive impairment after systemic treatment occurs in a subset of BC patients. The predictive value of demographic and psychosocial factors in cognitive impairment should be further investigated in a larger sample of impaired patients.