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

Neuromodulation through brain stimulation-assisted cognitive training in patients with post-chemotherapy subjective cognitive impairment (Neuromod-PCSCI) after breast cancer: study protocol for a double-blinded randomised controlled trial

INTRODUCTION

Breast cancer is the most common form of cancer in women. A considerable number of women with breast cancer who have been treated with chemotherapy subsequently develop neurological symptoms such as concentration and memory difficulties (also known as 'chemobrain'). Currently, there are no validated therapeutic approaches available to treat these symptoms. Cognitive training holds the potential to counteract cognitive impairment. Combining cognitive training with concurrent transcranial direct current stimulation (tDCS) could enhance and maintain the effects of this training, potentially providing a new approach to treat post-chemotherapy subjective cognitive impairment (PCSCI). With this study, we aim to investigate the effects of multi-session tDCS over the left dorsolateral prefrontal cortex in combination with cognitive training on cognition and quality of life in women with PCSCI.

METHODS AND ANALYSIS

The Neuromod-PCSCI trial is a monocentric, randomised, double-blind, placebo-controlled study. Fifty-two women with PCSCI after breast cancer therapy will receive a 3-week tDCS-assisted cognitive training with anodal tDCS over the left dorsolateral prefrontal cortex (target intervention), compared with cognitive training plus sham tDCS (control intervention). Cognitive training will consist of a letter updating task. Primary outcome will be the performance in an untrained task (n-back task) after training. In addition, feasibility, safety and tolerability, as well as quality of life and performance in additional untrained tasks will be investigated. A follow-up visit will be performed 1 month after intervention to assess possible long-term effects. In an exploratory approach, structural and functional MRI will be acquired before the intervention and at post-intervention to identify possible neural predictors for successful intervention.

ETHICS AND DISSEMINATION

Ethical approval was granted by the ethics committee of the University Medicine Greifswald (BB236/20). Results will be available through publications in peer-reviewed journals and presentations at national and international conferences.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov; NCT04817566, registered on 26 March 2021.

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.

Effects of non-pharmacological interventions on cancer-related cognitive impairment in patients with breast cancer: A systematic review and network meta-analysis

PURPOSE

To compare and rank the effectiveness of non-pharmacological interventions on cancer-related cognitive impairment (CRCI) for breast cancer patients.

METHODS

A systematic review and network meta-analysis were conducted following PRISMA guidelines. Randomized controlled trials from January 1, 2000 to October 11, 2024 were searched in nine electronic databases. Studies involving non-pharmacological interventions for managing CRCI in breast cancer were included. Methodological quality was assessed using the Cochrane Collaboration's Risk of Bias 2 assessment tool. Stata 15 was used for data analysis.

RESULTS

A total of 42 eligible studies were identified, covering eight non-pharmacological interventions. Psychological interventions (98.7%), Tai Chi/Qigong/Baduanjin (74.5%), and cognitive rehabilitation (70.1%) were the three most effective methods to improve subjective cognition. Cognitive training showed the highest effectiveness for working memory and executive function, with effectiveness rates of 78.3% and 83.4%, respectively. Cognitive rehabilitation (87.1%) was also the most effective for learning memory., while meditation/mindfulness-based stress reduction (71.8%) led in processing speed.

CONCLUSIONS

This network meta-analysis found that psychological interventions was the most effective for improving subjective outcomes. cognitive training proved most effective for working memory and executive function, while cognitive rehabilitation was most effective in enhancing learning memory, and meditation/mindfulness-based stress reduction ranked highest for processing speed.

Pilot randomized study of adaptive cognitive training's effect on breast cancer survivors assessed through eye tracking

PURPOSE

Cancer-related cognitive impairment (CRCI) is a prevalent comorbidity among breast cancer survivors, yet evidence supporting the efficacy of adaptive cognitive training remains limited. This pilot study seeks to examine participants' adherence and preliminary effect of tablet-based cognitive training as an intervention for CRCI and apply eye tracking technology as an innovative approach to evaluate cognitive training outcomes.

METHODS

Fifty-two eligible participants were randomly assigned to either the biofeedback therapy group (BF) or the combined biofeedback therapy and cognitive training group (BF + COG). Participants completed a 30-session intervention lasting 6 weeks and eye tracking assessments at two timepoints: baseline and immediately after the intervention completion.

RESULTS

Retention rates were 68% in the BF group and 70.4% in the BF + COG group. At the 6-week follow-up, the BF + COG group demonstrated significantly improved fixation stability. Under non-interfering conditions, they maintained fixation 307.76 ms longer (p = 0.022, Cohen's d = 0.307) and had a 32.4% reduction in saccadic distance (p = 0.019, Cohen's d = -0.677) compared to BF. This advantage persisted under interference conditions with a 28.2% shorter saccadic distance (p = 0.034, Cohen's d = -0.579). While within-group changes were not significant, the BF+COG group consistently showed reduced saccade distances across conditions, whereas the BF group exhibited increases.

CONCLUSION

Adaptive cognitive training may enhance attentional engagement and inhibitory control in breast cancer survivors. Large-scale study is needed to confirm these effects and refine eye-tracking applications for CRCI assessment.

IMPLICATIONS FOR CANCER SURVIVORS

Tablet-based cognitive training targeting cognitive control with adaptive difficulty levels may ameliorate CRCI among breast cancer survivors.

The effect of non-pharmacological interventions on cognitive function in cancer: an overview of systematic reviews

PURPOSE

A significant number of cancer survivors experience cancer-related cognitive impairment (CRCI), which can impact their ability to think, reason, make decisions, and perform daily actions. In recent years, non-pharmacological interventions for CRCI have gained significant attention. These interventions include exercise, cognitive behavioural therapy, cognitive training/remediation, dietary, mind-body, and multi-modal/complex interventions. This umbrella review provides a critical overview to inform guidelines and current practice, identify the most promising interventions, and uncover gaps in the research literature.

METHODS

This umbrella review of systematic reviews was pre-registered on Open Science Framework and PROSPERO. Six databases were searched. Systematic reviews (SR) assessing any non-pharmacological interventions to improve cognition in cancer (any type) were included. The overview followed gold-standard guidelines and recommendations. The results were narratively synthesised, and descriptive statistics and effect size ranges were calculated.

RESULTS

Sixty-four (n = 64) SRs were included. Results were synthesised into four non-pharmacological domains. Cognitive training/rehabilitation had the strongest evidence for efficacy. Physical activity/exercise showed promising efficacy; however, the variability of findings was considerable. Mind-body and psychological/behavioural therapy interventions were limited, but there was evidence for short-term effectiveness. Multi-modal/complex interventions showed potential for improving cognition in cancer but were poorly defined.

CONCLUSIONS

Overall, non-pharmacological interventions demonstrated efficacy for improving cognition in cancer. There were limited intervention characteristics within domains which were consistently related to efficacy. Three key recommendations are provided for future research: (1) adopt harmonisation and reporting guidelines; (2) develop definitional guidelines of cognitive domains for CRCI research; and (3) assess intervention and participant characteristics associated with positive versus null/negative findings.

Germain D, Dorsey SG. The National Cancer Institute clinical trials planning meeting to address gaps in observational and intervention trials for cancer-related cognitive impairment

Cancer-related cognitive impairment is a broad term encompassing subtle cognitive problems to more severe impairment. The severity of this impairment is influenced by host, disease, and treatment factors, and the impairment affects patients before, during, and following cancer treatment. The National Cancer Institute (NCI) Symptom Management and Health-Related Quality of Life Steering Committee (SxQoL SC) convened a clinical trial planning meeting to review the state of the science on cancer-related cognitive impairment and develop phase II/III intervention trials aimed at improving cognitive function in cancer survivors with non-central nervous system disease and longitudinal studies to understand the trajectory of cognitive impairment and contributing factors. Participants included experts in the field of cancer-related cognitive impairment, members of the SxQoL SC, patient advocates, representatives from all 7 NCI Community Oncology Research Program research bases, and the NCI. Presentations focused on the following topics: measurement, lessons learned from pediatric and geriatric oncology, biomarker and mechanism endpoints, longitudinal study designs, and pharmacological and behavioral intervention trials. Panel discussions provided guidance on priority cognitive assessments, considerations for remote assessments, inclusion of relevant biomarkers, and strategies for ensuring broad inclusion criteria. Three clinical trial planning meeting working groups (longitudinal studies as well as pharmacological and behavioral intervention trials) convened for 1 year to discuss and report on top priorities and to design studies. The meeting experts concluded that sufficient data exist to advance phase II/III trials using selected pharmacological and behavioral interventions for the treatment of cancer-related cognitive impairment in the non-central nervous system setting, with recommendations included herein.

Effects of a motor and cognitive training program on executive function and different biomarkers related to muscle-brain crosstalk in breast cancer survivors: 3-arm randomised controlled BRAINonFIT study protocol

INTRODUCTION

Cancer-related cognitive impairment (CRCI) is a significant but often neglected issue for breast cancer survivors that reduces their quality of life. Physical exercise and cognitive training have emerged as promising strategies for CRCI; however, evidence regarding its effectiveness is still unknown. A recently developed motor-cognitive training (dual-tasks) is proposed to examine its efficacy on executive function, physical fitness, emotional symptomatology, and important muscle-brain crosstalk biomarkers.

METHODS

The BRAINonFIT study is a randomised, controlled, longitudinal (20 weeks), three-arm, parallel study with a follow-up phase (12 weeks). Breast cancer survivors (stage I-IIIA) with completed chemotherapy are recruited from QuirónSalud Hospital in Seville. Principal outcomes are executive functions, measured by the Trail Making Test, Stroop and Digit Span Backwards; physical fitness, assessed by muscle strength, cardiorespiratory fitness, and body composition; and several muscle-brain biomarkers analysed by immunoenzymatic assay (ELISA). Secondary endpoints are memory function, intelligence, learning ability, self-reported cognitive function, and emotional symptomatology. Assessments take place after the enrolment (baseline; T1), after completing the interventions (5 months after baseline; T2), and after completing the follow-up period (8 months after baseline; T3).

DISCUSSION

Given the importance of improving care for breast cancer survivors, this study will provide preliminary evidence for the effectiveness of cognitive-motor training (dual task) as a therapeutic strategy to improve CRCI. Moreover, addressing muscle-brain crosstalk by representative biomarkers will help to elucidate the underlying mechanisms by which this intervention may beneficially impact CRCI.

CLINICALTRIALS

gov: NCT06073717.

Effects of cognitive training on cognitive function in patients after cardiac surgery: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Postoperative cognitive deficits frequently occur in patients undergoing cardiac surgery, leaving them with reduced cognitive function. Cognitive training has been shown to improve cognitive function, however, the role in patients after cardiac surgery is unclear. In this study, we aimed to evaluate the effectiveness and safety of cognitive training in patients undergoing cardiac surgery.

METHOD

A systematic search of PubMed, Embase, Cochrane Library, CINAHL, Ovid Medline, Web of Science, CNKI, and Wanfang was conducted until March 2024. The risk of bias was assessed using the Cochrane Risk of Bias Tool. Data were meta-analyzed using RevMan 5.4 software. Potential bias and reliability of evidence were fairly assessed by using the Cochrane risk of bias method and the GRADE evidence grading method.

RESULTS

A total of 16 studies involving 1335 cardiac surgery patients were included in this study. Compared with the control group, the cognitive training group had a significantly lower incidence of postoperative cognitive dysfunction (RR 0.35, 95% CI 0.18-0.65, P = .001), significantly improved cognitive function (MD 2.54, 95% CI 1.27-3.81, P < .001), and a significantly higher quality of life-mental component (MD 5.22, 95% CI 2.32-8.13, P < .001), anxiety (MD -6.05, 95% CI -10.96 to -1.15, P = .02) and depression (MD -3.97, 95% CI -7.15 to -0.80, P = .01) were significantly improved between groups. However, the differences were not statistically significant for postoperative delirium (RR 1, 95% CI 0.38-2.65, P = 1.00) and postoperative hospitalization (MD -0.95, 95% CI -2.90 to 1.00, P = .34).

CONCLUSIONS

The present study, based on a low to moderate quality of evidence, suggests that cognitive training improves cognitive functioning, reduces the incidence of postoperative cognitive dysfunction, and has a positive impact on anxiety and depression in patients undergoing cardiac surgery. However, current evidence does not allow for the determination of effects on quality of life, postoperative delirium, and postoperative length of stay.

Computerized cognitive training improves cognitive function in primary breast cancer survivors

Cancer-related cognitive impairment has a significant impact on the quality of life and perceived cognitive ability of breast cancer patients and frequently affects attention, working memory, and executive function. Several interventional approaches to treat these deficits have been studied, including web-based cognitive training, but methods and timing in relation to cancer treatment are heterogeneous. Only few interventions start early after primary breast cancer treatment, a time when many patients report the greatest impairments in quality of life and cognition. In this randomized controlled pilot study, 31 breast cancer survivors with subjective cognitive deficits and a mean post-treatment duration of 6.6 months (SD = 9.3) were assigned to either 14 weeks of a web-based cognitive training program (training group, n = 16) or a control group (n = 15). All patients underwent detailed neuropsychological assessment, evaluation of patient-reported outcomes (PROMs), and neurological examination before (baseline, T1) and after (follow-up, T2) the intervention. Longitudinal (T1 vs. T2) and cross-sectional (T2) cognitive performance was assessed for both groups. Overall cognitive impairment significantly improved in the training group following training (56% vs 25%; p = 0.03, Phi = 0.51), but not in the control group (73% vs. 73%; p = 1) in the longitudinal analysis (T1 vs. T2). Specifically, the training group showed statistically significant improvement of executive functions (p = 0.004, Phi = 0.32). No effects of training on subjective cognitive deficits or PROMs were observed. Comparing cross-sectional cognitive performance at follow-up (T2), the training group showed a significantly lower rate of cognitive impairment overall (p = 0.007, Phi = 0.48) and a better cognitive performance for executive function (p = 0.04, Phi = 0.32) compared to the control group. In this prospective pilot study, web-based cognitive training was efficacious in improving overall cognitive performance and executive function. Importantly, this study investigated a web-based cognitive training for the immediate post-treatment phase, when up to 75% of breast cancer patients experience cognitive decline. These results indicate that cognitive training may improve neuropsychological outcomes for patients with breast cancer.

Transparency in Cognitive Training Meta-analyses: A Meta-review

Meta-analyses often present flexibility regarding their inclusion criteria, outcomes of interest, statistical analyses, and assessments of the primary studies. For this reason, it is necessary to transparently report all the information that could impact the results. In this meta-review, we aimed to assess the transparency of meta-analyses that examined the benefits of cognitive training, given the ongoing controversy that exists in this field. Ninety-seven meta-analytic reviews were included, which examined a wide range of populations with different clinical conditions and ages. Regarding the reporting, information about the search of the studies, screening procedure, or data collection was detailed by most reviews. However, authors usually failed to report other aspects such as the specific meta-analytic parameters, the formula used to compute the effect sizes, or the data from primary studies that were used to compute the effect sizes. Although some of these practices have improved over the years, others remained the same. Moreover, examining the eligibility criteria of the reviews revealed a great heterogeneity in aspects such as the training duration, age cut-offs, or study designs that were considered. Preregistered meta-analyses often specified poorly how they would deal with the multiplicity of data or assess publication bias in their protocols, and some contained non-disclosed deviations in their eligibility criteria or outcomes of interests. The findings shown here, although they do not question the benefits of cognitive training, illustrate important aspects that future reviews must consider.

Cancer-Related Cognitive Dysfunction: A Narrative Review for Clinical Practice

BACKGROUND

Cancer-related cognitive dysfunction (CRCD) is a major functional disorder in patients with cancer. This central nervous dysfunction is found in up to 60% of patients after tumour therapy, often significantly limits the quality of life, and significantly impedes participation in working life. For this reason, diagnosis and treatment of CRCD are of central importance. This narrative review is intended to provide an overview and support for practical clinical care with regard to diagnostics and therapeutic options.

SUMMARY

In Germany, CRCD has received insufficient attention in clinical practice due to the lack of guidelines for diagnosis and therapy. The pathophysiology is complex and cannot be explained by chemotherapeutic treatment alone. In addition to the tumour disease as such and the tumour therapy, psychological factors such as anxiety and depression as well as sleep disorders also play a significant role. Today, it is known that in addition to age, molecular genetic changes also have an effect on cognitive function. Morphologically, CRCD can be located in the frontal cortex and hippocampus. In addition to easy-to-use screening instruments such as the visual analogue scale, validated questionnaires such as the Questionnaire of Subjectively Experienced Deficits in Attention (FEDA) developed in Germany are also available. These allow the suspected diagnosis to be substantiated and the patient to be referred to further neurological, neuropsychological, or psycho-oncological diagnostics. Within the framework of further neuropsychological diagnostics, the International Cognition and Cancer Task Force (ICCTF) recommends testing learning, memory, processing speed, and executive functions. From the authors' point of view, a step-by-step diagnosis is recommended in order to avoid overdiagnosis. In clinical practice, graduation according to the "Common Terminology Criteria for Adversity Events" (CTCAE Version 5.0) is suitable for assessing the degree of severity. Cognitive training should be behaviourally oriented and include regular practice of cognitive skills to restore attention, psychomotor speed, memory, and executive functions. The best evidence is currently found for web-based training programmes that can be used by the patient at home. There is also evidence for mindfulness training and physical exercises. In particular, the combination of these three therapeutic elements currently seems to be the optimal treatment strategy for CRCD.

KEY MESSAGES

Cognitive dysfunction should be given much more attention in the clinical care of cancer patients. Diagnostic tools for this purpose and evidence-based therapeutic interventions are available. In the future, networks should be created that allow for better care of patients with CRCD.

Neuroimaging based biotypes for precision diagnosis and prognosis in cancer-related cognitive impairment

Cancer related cognitive impairment (CRCI) is commonly associated with cancer and its treatments, yet the present binary diagnostic approach fails to capture the full spectrum of this syndrome. Cognitive function is highly complex and exists on a continuum that is poorly characterized by dichotomous categories. Advanced statistical methodologies applied to symptom assessments have demonstrated that there are multiple subclasses of CRCI. However, studies suggest that relying on symptom assessments alone may fail to account for significant differences in the neural mechanisms that underlie a specific cognitive phenotype. Treatment plans that address the specific physiologic mechanisms involved in an individual patient's condition is the heart of precision medicine. In this narrative review, we discuss how biotyping, a precision medicine framework being utilized in other mental disorders, could be applied to CRCI. Specifically, we discuss how neuroimaging can be used to determine biotypes of CRCI, which allow for increased precision in prediction and diagnosis of CRCI via biologic mechanistic data. Biotypes may also provide more precise clinical endpoints for intervention trials. Biotyping could be made more feasible with proxy imaging technologies or liquid biomarkers. Large cross-sectional phenotyping studies are needed in addition to evaluation of longitudinal trajectories, and data sharing/pooling is highly feasible with currently available digital infrastructures.

Young Adults' Lived Experiences with Cancer-Related Cognitive Impairment: An Exploratory Qualitative Study

Cancer-related cognitive impairment (CRCI; e.g., disrupted memory, executive functioning, and information processing) affects many young adults, causing significant distress, reducing quality of life (QoL), and thwarting their ability to engage in professional, recreational, and social experiences. The purpose of this exploratory qualitative study was to investigate young adults' lived experiences with CRCI, and any strategies (including physical activity) they use to self-manage this burdensome side effect. Sixteen young adults (Mage = 30.8 ± 6.0 years; 87.5% female; Myears since diagnosis = 3.2 ± 3) who reported clinically meaningful CRCI whilst completing an online survey were interviewed virtually. Four themes comprising 13 sub-themes were identified through an inductive thematic analysis: (1) descriptions and interpretations of the CRCI phenomenon, (2) effects of CRCI on day-to-day and QoL, (3) cognitive-behavioural self-management strategies, and (4) recommendations for improving care. Findings suggest CRCI is detrimental to young adults' QoL and must be addressed more systematically in practice. Results also illuminate the promise of PA in coping with CRCI, but research is needed to confirm this association, test how and why this may occur, and determine optimal PA prescriptions for young adults to self-manage their CRCI.

Does participation in therapeutic exercise programs after finishing oncology treatment still ensure an adequate health status for long-term breast cancer survivors? A ≥ 5 years follow-up study

PURPOSE

The aims of this study were to evaluate whether the effects of two therapeutic exercise programs are sustained over time (≥ 5 years) in long-term breast cancer survivors (LTBCS). Second, to determine the influence of the current level of physical activity (PA) performed on cancer-related fatigue (CRF) that these patients may present ≥5 years later.

METHODS

A prospective observational study was conducted with a cohort of 80 LTBCS in Granada during 2018. Firstly, considering their participation in one of the programs, they were allocated into two groups: usual care and therapeutic exercise program, to assess CRF, pain and pressure pain sensitivity, muscle strength, functional capacity, and quality of life. Secondly, they were also classified into 3 groups according to current level of weekly PA performed: ≤ 3, 3.1-7.4, and ≥ 7.5 (MET-hour/week) respectively, to assess its impact over CRF.

RESULTS

Although the positive effects of the programs are not sustained over time, a trend toward significance can be observed for a greater reduction in overall CRF levels, lower intensity of pain in the affected arm and cervical region, and greater functional capacity and quality of life in the group that underwent therapeutic exercise. Additionally, 66.25% of LTBCS are inactive ≥ 5 years after completion of the program and furthermore, such inactivity is accompanied by higher CRF levels (P .013 to .046).

CONCLUSION

The positive effects of therapeutic exercise programs are not maintained over time for LTBCS. Additionally, more than half of these women (66.25%) are inactive ≥ 5 years after completion of the program, this inactivity being accompanied by higher levels of CRF.