Self-rated cognitive functions following chemotherapy in patients with breast cancer: a 6-month prospective study

PURPOSE The purpose of the study was to evaluate subjective (self-rated), family-rated, and objective (researcher-rated) cognitive functions in patients with breast cancer after chemotherapy. METHOD We conducted a prospective study to trace self-rated cognitive functions in 30 patients with breast cancer at the completion of chemotherapy (T0) and 6 months later (T1). Subjective cognitive functions were assessed with Cognitive Failures Questionnaire (CFQ), Dysexecutive Questionnaire (DEX-S), and Everyday Memory Checklist (EMC-S) for attention, executive function, and episodic memory, respectively. Their family members also completed DEX-I and EMC-I for executive function and episodic memory, respectively. We also examined objective cognitive functions. Self-rated cognitive functions were compared with the normative data. They were compared between T0 and T1. We calculated correlation coefficients between self-rated and other cognitive functions. RESULTS At T0, 6 (20.0%) and 2 (6.7%) participants showed higher DEX-S and EMC-S scores than the normative data, respectively, while no participant had abnormal CFQ scores. At T1, DEX-S and EMC-S scores were normalized in 3 (50.0%) and 2 (100.0%) participants, respectively. No participant showed increases in CFQ scores. No changes were found in objective cognitive functions from T0 to T1. DEX-S and DEX-I or EMC-S and EMC-I scores were correlated at both T0 and T1, which did not survive multiple corrections. There was no association between subjective and objective cognitive functions. CONCLUSION Impairments in subjective cognition may be transient after chemotherapy in patients with breast cancer. Furthermore, patients and their families appear to share similar prospects on their cognitive functions.