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.

Identifying themes for assessing cancer-related cognitive impairment identified by topic modeling and qualitative content analysis of public online comments (Preprint)

Background

Cancer-related cognitive impairment (CRCI) is a common and significant adverse effect of cancer and its therapies. However, its definition and assessment remain difficult due to limitations of currently available measurement tools.

Objective

This study aims to evaluate qualitative themes related to the cognitive effects of cancer to help guide development of assessments that are more specific than what is currently available.

Methods

We applied topic modeling and inductive qualitative content analysis to 145 public online comments related to cognitive effects of cancer.

Results

Topic modeling revealed 2 latent topics that we interpreted as representing internal and external factors related to cognitive effects. These findings lead us to hypothesize regarding the potential contribution of locus of control to CRCI. Content analysis suggested several major themes including symptoms, emotional/psychological impacts, coping, “chemobrain” is real, change over time, and function. There was some conceptual overlap between the 2 methods regarding internal and external factors related to patient experiences of cognitive effects.

Conclusions

Our findings indicate that coping mechanisms and locus of control may be important themes to include in assessments of CRCI. Future directions in this field include prospective acquisition of free-text responses to guide development of assessments that are more sensitive and specific to cognitive function in patients with cancer.

Cognitive effects of chemotherapy: An integrative review

PURPOSE

An estimated 18.1 million new cancer cases (excluding nonmelanoma skin cancers) were diagnosed worldwide in 2020. Despite a rising incidence of cancers worldwide, in developed countries with strong healthcare systems, survival rates are improving as a result of early detection, improved treatments and survivorship care (World Health Organisation (WHO), 2021). Whilst living longer, cancer survivors are often living with side effects of treatment, including chemotherapy related cognitive impairment, often termed "chemobrain".

METHOD

An integrative review of contemporary literature answering the research question how does chemotherapy affect cognitive function? was undertaken utilising three computerised databases CINAHL, Medline and PUBMED, between 2015 and 2021. Data was thematically analysed to identify themes within published literature.

RESULTS

Thematic analysis identified four broad themes within the literature regarding chemotherapy induced cognitive impairment. Identified themes included; cognition as part of a complex scenario, proof of existence and searching for the cause, learning to play the game and timing of cognitive impairment.

CONCLUSIONS

Aggressive treatment with chemotherapy in the adjuvant setting has drastically improved the survival of cancer patients. Subsequent to aggressive treatments, side effects such as cognitive impairment have presented, which may persist in the long term. Despite the exact aetiology of chemotherapy induced cognitive impairment being largely unknown, the consequences of the condition are impacting cancer survivors and their quality of life.

[Early and Late Toxicities and Socio-Medical Relevant Disorders after Oncological Treatment for Breast Cancer-Implications and Assessment of Rehabilitation Requirement]

INTRODUCTION

Reasonable to the improved prognosis of breast cancer (BC) long-term toxicities and side effects of oncological therapy gain more importance for work ability and social life of BC patients. Aim of this study was the analysis of occurence and differences of treatment-related side effects in relation to type of rehabilitation (so-called AHB vs. later rehabilitation) after therapy for BC.

METHODS

Clinical and patient related data as early and late toxicities after oncological treatment of 8.000 patients with BC (55.7±10.4y) were analyzed and compared with current literature.

RESULTS

In 23.9% a mastectomy was performed, in 87.3% radiotherapy. In most cases an additional systemic treatment (57,6% CTX, 15,1% anti-Her2, 71% antihormonal treatment) was carried out. In 8.1% women suffered from recurrent or metastatic BC. As most common side effects of multimodal treatment weakness/fatigue (73,6%), insomnia (51,9%), CIPN (33%), lymph edema (13,9%) and drug-induced arthralgia (24,8%) were detected. In addition, 60.4% of women reported high levels of psychological distress. Shortly after therapy typical side effects were drug-induced toxicities (Leucopenia, p<0.0001; anemia, p<0.001; weakness/fatigue p<0.001; CIPN, p<0.0001), whereas in a later course chronic lymphedema (p<0.0001), chronic or recurrent disease (p<0.0001), status after mastectomy (p<0.0001) and psychological distress (p<0.0001) were significantly more often seen. Moreover, in this collective patients were significantly younger (53,7±9,8 vs. 56,3±10,7y).

CONCLUSIONS

In BC patients, significantly different impairments and toxicities were documented between patients with early rehabilitation and patients with later onset of rehabilitation. These data may help to establish more individual and focused rehabilitation concepts in specialized centers.

[Role of Clinical, Sociomedical and Psychological Factors on Return to Work of Patients with Breast Cancer 6 Months after Rehabilitation]

AIM OF THE STUDY

The majority of patients with non-metastatic breast cancer return to work after tumor therapy. A rate of up to 80% is given in national and international studies, which can vary considerably depending on the study population and the various social systems. However, it is unclear how many patients are reintegrated into work after medical rehabilitation and which clinical, sociodemographic and psychological factors play a role.

METHODS

In a multicentre study, clinical and sociodemographic data were collected from breast cancer patients at the beginning of their medical rehabilitation. Subjectively experienced deficits in attention performance (FEDA), depressive symptoms (PHQ-9) and health-related quality of life (EORTC QLQ-C30) were recorded using standardized questionnaires. The cognitive performance was also examined using a computer-based test battery (NeuroCog FX). A follow-up survey was carried out 6-9 months after medical rehabilitation. The subjective assessment of one's own cognitive performance (FEDA) was recorded again at this time.

RESULTS

396 of the originally 476 patients were included in the study. In the follow-up survey, 323/396 patients (82%) were again employed. In a regression model, sociodemographic factors proved to be particularly predictive with regard to occupational reintegration: employment at the time of the tumor diagnosis, job preserved after medical rehabilitation, employee status and gradual reintegration according to the Hamburg model (Nagelkerke R²=0.685). This model could not be improved by adding psychological variables. The subjective patient information in all questionnaires was highly correlated (r>0.57; p<0.001).

CONCLUSION

The vast majority of breast cancer patients return to work after medical rehabilitation. Socio-demographic factors play a crucial role in this. The regression model developed here, including the employment status, professional orientation and gradual reintegration, is of predictive importance and can be used in medical rehabilitation.

Effects of brief acceptance and commitment therapy (ACT) on subjective cognitive impairment in breast cancer patients undergoing chemotherapy

PURPOSE

This study examined the efficacy of a brief acceptance and commitment therapy (ACT) on subjective cognitive impairment in breast cancer patients undergoing chemotherapy.

METHODS

Data collection was carried out in 3-time points: baseline (T1), screening (T2), and post-treatment (T3). Respondents who had significant subjective cognitive impairment were randomly divided into two groups: intervention (n = 30) and waitlist (n = 30). Respondents in the intervention group received 4 sessions of 1 hour of ACT therapy.

FINDINGS

Respondents in the intervention group showed significant improvement in subjective cognitive impairment, depression, anxiety, and psychological inflexibility after the ACT intervention (p < 0.05). After controlling the covariates, group differences in all variables were significant except for fatigue and psychological inflexibility has the highest effect size (d = 4.69).

CONCLUSION

ACT could be considered as an effective intervention to ameliorate subjective cognitive impairment, anxiety, depression, and psychological inflexibility in breast cancer patients undergoing chemotherapy.

IMPLICATIONS FOR PSYCHOSOCIAL PROVIDERS

This study highlights the importance of screening for subjective cognitive impairment in breast cancer patients undergoing chemotherapy and heightens their opportunity to receive proper management as earlier as possible.

Network-level functional connectivity alterations in chemotherapy treated breast cancer patients: a longitudinal resting state functional MRI study

Background

Previous studies have found abnormal structural and functional brain alterations in breast cancer survivors undergoing chemotherapy. However, the network-level brain changes following chemotherapy remain unknown. The purpose of this study was to investigate the dynamic changes of large-scale within- and between-network functional connectivity in chemotherapy-treated breast cancer patients.

Methods

Seventeen breast cancer patients were evaluated with resting state functional MRI (rs-fMRI), neuropsychological tests and blood examination before postoperative chemotherapy (t0), one week after completing chemotherapy (t1) and six months after completing chemotherapy (t2). Nineteen age- and education level-matched healthy controls (HC) were also recruited. Independent components analysis (ICA) was performed to assess network component using rs-fMRI data. The functional network changes were then correlated with cognitive assessment scores and blood biochemical indexes.

Results

One-way repeated measures ANOVA revealed significantly changed within-network functional connectivity in the anterior and posterior default mode network (ADMN and PDMN), left and right frontoparietal network (LFPN and RFPN), visual network and self-referential network. Post-hoc test showed that decreased within-network functional connectivity in ADMN, PDMN, LFPN, RFPN, SRN and central network one week after chemotherapy and increased six months after chemotherapy (all P < 0.05). As for the between-network functional connectivity, the PDMN- sensorimotor network connectivity showed the same tendency. Most of these within- and between-network functional connectivity changes were negatively associated with blood biochemical indexes and cognitive assessment scores (all P < 0.05).

Conclusions

These results indicated that chemotherapy may induce widespread abnormalities in resting state networks, which may serve as a potential biomarker of chemotherapy related cognitive impairment, providing insights for further functional recovery treatment.

Chemotherapy-induced brain changes in breast cancer survivors: evaluation with multimodality magnetic resonance imaging

Chemotherapy related cognitive impairments are common in breast cancer patients undergoing chemotherapy. These cognitive dysfunctions are mainly attributable to chemotherapy related brain structural and functional alterations. Multimodality magnetic resonance imaging (MRI) can reveal brain gray matter volume loss, white matter microstructural disruption, reduced gray matter density, impaired cerebral blood flow and brain structural and functional connection networks at both local and global levels. This review outlines the potential applications of multimodality MR imaging techniques in chemotherapy induced cognitive deficit in breast cancer survivors and provides future research perspective in this field.

Cognitive Performance and Psychological Distress in Breast Cancer Patients at Disease Onset

Objective

Many cancer patients complain about cognitive dysfunction. While cognitive deficits have been attributed to the side effects of chemotherapy, there is evidence for impairment at disease onset, prior to cancer-directed therapy. Further debated issues concern the relationship between self-reported complaints and objective test performance and the role of psychological distress.

Method

We assessed performance on neuropsychological tests of attention and memory and obtained estimates of subjective distress and quality of life in 27 breast cancer patients and 20 healthy controls. Testing in patients took place shortly after the initial diagnosis, but prior to subsequent therapy.

Results

While patients showed elevated distress, cognitive performance differed on a few subtests only. Patients showed slower processing speed and poorer verbal memory than controls. Objective and self-reported cognitive function were unrelated, and psychological distress correlated more strongly with subjective complaints than with neuropsychological test performance.

Conclusion

This study provides further evidence of limited cognitive deficits in cancer patients prior to the onset of adjuvant therapy. Self-reported cognitive deficits seem more closely related to psychological distress than to objective test performance.

Is the computerized assessment of psychomotor speed more sensitive to cognitive effects of antiepileptic pharmacotherapy than tests with a focus on higher-order cognitive processing? Implications for the choice of sensitive test parameters

The study evaluated whether it is psychomotor speed or higher-order cognitive processing which is primarily affected by antiepileptic drug (AED) treatment in epilepsy and whether computerized testing versus paper-pencil testing of executive functions is more sensitive. In this retrospective observational study, 55 patients with epilepsy underwent NeuroCog FX^Ⓡ, a computerized battery assessing "psychomotor speed/alertness" and "cognitive processing" via 8 tasks, and EpiTrack^Ⓡ, a paper-pencil screening of "executive functions and working memory" based on 6 subtests. Test performance was related to the number of drugs and the Defined Daily Dose and the presence/absence of AEDs with known adverse psychotropic effects. EpiTrack^Ⓡ performance correlated with "cognitive processing" of the NeuroCog FX^Ⓡ but not with "psychomotor speed/alertness". Significant correlations with drug load were mainly yielded for EpiTrack^Ⓡ (number of AEDs: r = -0.551, total DDD: r = -0.452) and "cognitive processing" (number of AEDs: r = -0.433, total DDD: r = -0.415). "Psychomotor speed/alertness" was less related to drug load (number of AEDs: r = -0.285, total DDD: r = -0.232). Statistical control for "psychomotor speed/alertness" hardly changed the correlations of EpiTrack^Ⓡ or "cognitive processing" with drug load indices. AEDs with known adverse profiles negatively affected EpiTrack^Ⓡ and the "cognitive processing" but not the "psychomotor speed/alertness" domain of the computerized test. The results demonstrate that it is less basal psychomotor speed than higher-order cognitive processing which is negatively affected by antiepileptic pharmacotherapy. The results question the value of (computer-)tests with a major emphasis on psychomotor speed and alertness for cognitive drug monitoring.