Effect of cognitive training on patients with breast cancer reporting cognitive changes: a systematic review and meta-analysis

Objectives Cognitive training is a non-drug intervention to improve the cognitive function of participants by training them in different cognitive domains. We investigated the effectiveness of cognitive training for patients with breast cancer reporting cognitive changes. Design Systematic review and meta-analysis. Data sources PubMed, Embase, Cochrane Library, WOS, CINAHL, CNKI, VIP, SinoMed, Wanfang, Grey literature and trial registries were searched (from inception to 1 October 1, 2022). Eligibility criteria Inclusion of randomized controlled trials (RCTs) assessing the effects of cognitive training on breast cancer patients reporting cognitive changes The primary outcome was subjective cognitive function. Secondary outcomes were objective cognitive functioning (eg, executive functioning and attention) and psychological outcomes(eg, anxiety, depression, and fatigue). Data extraction and synthesis Two reviewers worked independently to screen the literature, extract data, and assess the methodological quality and risk bias of the included studies. Results are reported as standardizedstandardised mean differences (SMDs) with 95% confidence intervals(CI). Grades of Recommendation, Assessment, Development, and Evaluation(GRADE) were used to assess the quality of evidence. Main outcomes and measures The primary outcome was subjective cognitive function. Secondary outcomes were objective cognitive functioning (eg, executive functioning and attention) and psychological outcomes(eg, anxiety, depression and fatigue). Results A total of 9 RCTs involving 666 patients with breast cancer were included. The frequency of cognitive training varied and the duration was mostly focused on 5-12 weeks. It can be delivered to patients in an individual or group mode, both online and face to face. Meta-analysis revealed that cognitive training aimed at adaptive training in cognitive field has statistically significant effects on improving subjective cognitive function (SMD=0.30, 95% CI (0.08 to 0.51), moderate certainty). Some objective cognitive functions such as processing speed (SMD=0.28, 95% CI (0.02 to 0.54), low certainty), verbal memory (SMD=0.32, 95% CI (0.05 to 0.58), moderate certainty), working memory (SMD=0.39, 95% CI (0.17 to 0.61), moderate certainty) and episodic memory (SMD=0.40, 95% CI (0.11 to 0.69), moderate certainty) were significantly improved after the intervention. In addition, we did not find statistically significant changes in attention, short-term memory, execution function, depression, anxiety and fatigue in patients with breast cancer after the intervention. Subgroup analyses revealed that based on the delivery of individual sessions, the use of web-based cognitive training software may be more beneficial in improving the outcome of the intervention. Conclusion Evidence of low to moderate certainty suggests that cognitive training may improve subjective cognition, processing speed, verbal memory, working memory and episodic memory in patients with breast cancer reporting cognitive changes. But it did not improve patients' attention, short-term memory, executive function, depression, anxiety and fatigue.