Effects of chemotherapy on attention function in breast cancer patients: Meta-analysis of longitudinal prospective cohort studies

Purpose: This study aimed to quantify the impact of chemotherapy on attention function, assessed by neuro-psychological tests and to identify the time point of impact. Methods: This is a meta-analysis with 16 independent data sets from 18 studies. Literature was searched in 5 databases. We calculated Hedges’ g as an effect size (ES) for mean differences between groups by time point: chemotherapy treated patients (CTX group); nonchemotherapy patients (NCP group); and healthy control (HC group). The neuropsychological tests were classified and analyzed separately: time spent and correct or incorrect answer count. Results: In both tests, the CTX and NCP groups did not differ. Yet, after excluding an influential study in the answer-based test, the CTX group showed significantly lower attention function than the NCP group at within 1 year post-CTX(ES = −0.22, p = 0.03). In both tests, the CTX group had significantly lower attention function than HC at within 1 year post-CTX (ES = 0.36, p = 0.05; ES = −0.30, p < 0.01). Contrarily, the NCP and HC groups did not differ at each follow-up time. ES was largest at within 1 year post-CTX, suggesting the CTX impact on attention function may be delayed, not acute. Conclusion: This study provide the evidence that CTX deteriorates patients' attention function, beyond patients’ subjective experience. Yet, findings from individual studies were mixed and some of them greatly influenced the overall effect of chemotherapy, requiring additional well-designed studies. Clinicians must know the impact of chemotherapy on attention functions and available supportive cares. Registration number: PROSPERO CRD42023481642.