Cognitive function in breast cancer survivors

Efficacy of Mindfulness-Based Stress Reduction for Breast Cancer (MBSR(BC)) a Treatment for Cancer-related Cognitive Impairment (CRCI): A Randomized Controlled Trial

Introduction: The Mindfulness-Based Stress Reduction (MBSR) Program for breast cancer survivors (BCS) is designed to enhance cognitive training through formal and informal meditational practices. This randomized clinical trial (RCT) aimed to evaluate if BCS assigned to either the MBSR(BC), Breast Cancer Education Support (BCES), or Usual Care (UC) regimens experienced greater improvements at 6, 12, and 26 weeks on objective and subjective cognitive performance. Methods: BCS (n = 212) randomized to a three-group RCT: MBSR(BC) (n = 91), BCES (n = 90), or UC (n = 31) were assessed on cognitive performance and symptoms at baseline, 6, 12, and 26 weeks. Linear mixed models were fit to evaluate the effects of the MBSR(BC) program, hypothesizing ordered effect improvements: (MBSR[BC] highest, BCES intermediate, UC lowest) along with baseline characteristics evaluated as moderators. Results: Of the BCS (mean age of 57), 73% were White, and non-Hispanic, and 77% received both chemotherapy (CT) and radiation. Cognitive performance improved in all groups. Although there were no statistically significant between-group differences in cognitive outcomes, significant symptom reductions occurred for the MBSR(BC) group (p = 0.003). Within-group effect size analysis at 26 weeks showed substantial improvements in all three groups (effect sizes >0.50) in subjective impairments and quality of life (effect size >0.50) and objective measures of cognitive performance. MBSR(BC) showed the largest within-group effect size in the reduction of fatigue (effect size = 0.81). Effect sizes occurred in the hypothesized direction for 10 of the 18 outcomes. Discussion: Although the MBSR(BC) program did not show significant differences in cognitive performance compared with BCES and UC, all groups improved and reductions in fatigue were beneficial for MBSR(BC). Results suggest that cognitive performance may improve after CT over time considering one's natural history. Furthermore, BCS enrolled in RCTs may be more motivated to improve their health status (NCT02786797).

Neurologic Complications in Adult Cancer Survivorship

Over the past decade, the improvement in cancer diagnostics and therapeutics has extended the overall survival of patients diagnosed with cancer including brain cancer. However, despite these unprecedented medical successes, patients continue to experience numerous neurologic complications after treatment that interfere with their independence, functionality, and overall quality of life. These include, among others, cognitive impairment, endocrinopathies, peripheral and cranial neuropathies, and vasculopathy. This article describes the long-term neurologic complications cancer survivors commonly experience to increase awareness of these complications and discuss treatments when available. Further research is necessary to understanding of mechanisms of neurologic injury and advance diagnosis and treatment. Effective patient education, monitoring, and managing neurologic issues after cancer treatment may improve independence, functionality, and quality of life during survivorship.

Psychological Aspects of Breast Cancer

Breast cancer is the most commonly diagnosed cancer in women. Associated psychological symptoms include stress, adjustment difficulties, anxiety, depression, impaired cognitive function, sleep disturbances, altered body image, sexual dysfunction, and diminished overall well-being. Distress screening and assessment identifies women who will benefit from therapeutic interventions. Addressing these symptoms improves compliance with treatment and outcomes including disease-related outcomes, psychological symptoms, and quality of life. The most effective treatments include teaching coping skills such as expressing emotion, along with other structured cognitive behavioral, interpersonal, and mindfulness approaches. Patients should be provided these psychosocial supports throughout their cancer journey.

Subjective cancer-related cognitive impairments and salience network connectivity in breast cancer survivors

PURPOSE

Little is known about the neural basis of subjective cancer-related cognitive changes. The purpose of this study was to explore salience network connectivity in relation to subjective executive and memory dysfunction in breast cancer survivors compared to controls.

METHODS

A retrospective cross-sectional analysis of neuroimaging, subjective cognitive, clinical, and demographic data in chemotherapy-treated primary breast cancer survivors compared to frequency matched controls was used. Functional connectivity within salience network hubs (anterior cingulate, bilateral insula) was determined using resting state functional MRI. Mann-Whitney U tests were used to evaluate group differences and Spearman's rho correlations were examined among the behavioral measures and salience network connectivity.

RESULTS

We included 65 breast cancer survivors and 71 controls. Survivors demonstrated greater subjective executive dysfunction and memory complaints (p < .001) and lower salience network connectivity (p < .05) than controls. Executive functioning correlated with bilateral insula and left anterior cingulate connectivity (rho >  - 0.29, p < .05). Distress did not correlate with salience network connectivity.

CONCLUSION

These findings suggest that salience network connectivity may represent a biomarker of subjective cancer-related cognitive changes.

IMPLICATIONS FOR CANCER SURVIVORS

Subjective cancer-related cognitive changes are common following treatment and associated with objective changes in brain connectivity.

Detecting microstructural alterations of cerebral white matter associated with breast cancer and chemotherapy revealed by generalized q-sampling MRI

Objective

Previous studies have discussed the impact of chemotherapy on the brain microstructure. There is no evidence of the impact regarding cancer-related psychiatric comorbidity on cancer survivors. We aimed to evaluate the impact of both chemotherapy and mental health problem on brain microstructural alterations and consequent cognitive dysfunction in breast cancer survivors.

Methods

In this cross-sectional study conducted in a tertiary center, data from 125 female breast cancer survivors who had not received chemotherapy (BB = 65; 49.86 ± 8.23 years) and had received chemotherapy (BA = 60; 49.82 ± 7.89 years) as well as from 71 age-matched healthy controls (47.18 ± 8.08 years) was collected. Chemotherapeutic agents used were docetaxel and epirubicin. We used neuropsychological testing and questionnaire to evaluate psychiatric comorbidity, cognitive dysfunction as well as generalized sampling imaging (GQI) and graph theoretical analysis (GTA) to detect microstructural alterations in the brain.

Findings

Cross-comparison between groups revealed that neurotoxicity caused by chemotherapy and cancer-related psychiatric comorbidity may affect the corpus callosum and middle frontal gyrus. In addition, GQI indices were correlated with the testing scores of cognitive function, quality of life, anxiety, and depression. Furthermore, weaker connections between brain regions and lower segregated ability were found in the post-treatment group.

Conclusion

This study suggests that chemotherapy and cancer-related mental health problem both play an important role in the development of white matter alterations and cognitive dysfunction.

Neurological Complications of Conventional and Novel Anticancer Treatments

Various neurological complications, affecting both the central and peripheral nervous system, can frequently be experienced by cancer survivors after exposure to conventional chemotherapy, but also to modern immunotherapy. In this review, we provide an overview of the most well-known adverse events related to chemotherapy, with a focus on chemotherapy induced peripheral neurotoxicity, but we also address some emerging novel clinical entities related to cancer treatment, including chemotherapy-related cognitive impairment and immune-mediated adverse events. Unfortunately, efficacious curative or preventive treatment for all these neurological complications is still lacking. We provide a description of the possible mechanisms involved to drive future drug discovery in this field, both for symptomatic treatment and neuroprotection.

Effects of meditation compared to music listening on biomarkers in breast cancer survivors with cognitive complaints: secondary outcomes of a pilot randomized control trial

CONTEXT

We previously reported positive behavioral effects of both daily mantra meditation and classical music listening interventions in breast cancer survivors with cancer related cognitive complaints.

OBJECTIVE

The objective of this pilot study was to compare the effects of the meditation intervention to a music listening intervention on biomarkers of inflammation and cellular aging (secondary outcomes) in breast cancer survivors.

DESIGN

Randomized control trial, baseline data collection (time 1), post intervention data collection (time 2) SETTING: Community-based, Central Texas PARTICIPANTS: 25 breast cancer survivors (BCS) who were 3 months to 6 years post chemotherapy completion and reported cognitive changes.

INTERVENTION(S)

Kirtan Kriya meditation (KK) or classical music listening (ML), 8 weeks, 12 min a day MAIN OUTCOME: Telomerase activity [TA], c-reactive protein [CRP], soluble IL-2 receptor alpha [sIL-2Rα], soluble IL-4 receptor [sIL-4R], soluble IL-6 receptor [sIL-6R], soluble tumor necrosis factor receptor II [sTNF-RII], VEGF receptor 2 [sVEGF-R2], and VEGF receptor 3 [sVEGF-R3] RESULTS: Repeated measures analysis of variance models were analyzed from time 1 to time 2 by group for each biomarker. A pattern of greater telomerase activity across time in both groups (F (1,15) = 3.98, p = .06, ω2 = 0.04); significant decreases in sIL-4R across time for both groups (F (1,22) = 6.28, p = .02, ω2 = .003); group*time effect was nominally different but not statistically different for sIL-4R (F(1,22) = 3.82, p = .06, ω2 = .001); and a pattern for a group*time effect with ML group showing higher levels of sVEGF-R3 at time 2 (F (1,20) = 2.59, p = .12, ω2 = .009). No significant effects were found for CRP, sIL-2Rα, sIL-6R, sTNF-RII, or sVEGF-R2.

Prevalence of cognitive impairment following chemotherapy treatment for breast cancer: a systematic review and meta-analysis

Breast cancer survival rates have markedly improved. Consequently, survivorship issues have received increased attention. One common sequel of treatment is chemotherapy-induced cognitive impairment (CICI). CICI causes a range of impairments that can have a significant negative impact on quality of life. Knowledge of the prevalence of this condition is required to inform survivorship plans, and ensure adequate resource allocation and support is available for sufferers, hence a systematic review of prevalence data was performed. Medline, Scopus, CINAHL and PSYCHInfo were searched for eligible studies which included prevalence data on CICI, as ascertained though the use of self-report, or neuropsychological tests. Methodological quality of included studies was assessed. Findings were synthesised narratively, with meta-analyses being used to calculate pooled prevalence when impairment was assessed by neuropsychological tests. The review included 52 studies. Time-points considered ranged from the chemotherapy treatment period to greater than 10 years after treatment cessation. Summary prevalence figures (across time-points) using self-report, short cognitive screening tools and neuropsychological test batteries were 44%, 16% and 21-34% respectively (very low GRADE evidence). Synthesised findings demonstrate that 1 in 3 breast cancer survivors may have clinically significant cognitive impairment. Prevalence is higher when self-report based on patient experience is considered. This review highlights a number of study design issues that may have contributed to the low certainty rating of the evidence. Future studies should take a more consistent approach to the criteria used to assess impairment. Larger studies are urgently needed.

Comparison of functional dorsal attention network alterations in breast cancer survivors before and after chemotherapy

ABSTRACT

Breast cancer is the leading type of cancer among women worldwide, and a high number of breast cancer patients are suffering from psychological and cognitive disorders. This cross-sectional study used resting-state functional magnetic resonance imaging (rs-fMRI) and clinical neuropsychological tests to evaluate the possible underlying mechanisms.We enrolled 32 breast cancer patients without chemotherapy (BC), 32 breast cancer patients within 6 to 12 months after the completion of chemotherapy (BC_CTx) and 46 healthy controls. Participants underwent neuropsychological tests and rs-fMRI with mean fractional amplitude of low-frequency fluctuation and mean regional homogeneity analyses. Between groups whole-brain voxel-wise rs-fMRI comparisons were calculated using two-sample t test. rs-fMRI and neuropsychological tests correlation analyses were calculated using multiple regression. Age and years of education were used as covariates. A false discovery rate-corrected P-value of less than .05 was considered statistically significant.We found significantly alteration of mean fractional amplitude of low-frequency fluctuation and mean regional homogeneity in the frontoparietal lobe and occipital lobe in the BC group compared with the other 2 groups, indicating alteration of functional dorsal attention network (DAN). Furthermore, we found the DAN alteration was correlated with neuropsychological impairment.The majority of potential underlying mechanisms of DAN alteration in BC patients may due to insufficient frontoparietal lobe neural activity to drive DAN and may be related to the effects of neuropsychological distress. Further longitudinal studies with comprehensive images and neuropsychological tests correlations are recommended.

"Chemobrain" in childhood cancer survivors - the impact on social, academic, and daily living skills: a qualitative systematic review protocol

OBJECTIVE

The objective of this review is to examine children's experiences of chemotherapy-induced cognitive impairment--also known as "chemobrain"--and the impact of chemobrain on children's social, academic, and daily living skills.

INTRODUCTION

The effect of childhood chemotherapy treatment on cognition is of concern because of the vulnerable nature of children's developing brains and the potential to cause lifelong detriments socially, academically, and economically. Furthermore, this population is underrepresented in the chemobrain literature and in survivorship care plans. As cancer survivorship among this group increases, it is important to understand childhood experiences so that rehabilitation strategies and suitable supports can be put in place.

INCLUSION CRITERIA

This review of qualitative studies will focus on the pediatric population (0-18 years of age) during and/or following chemotherapy treatment to identify their experiences with chemobrain. The review will include any studies using a qualitative research methodology (eg, surveys, focus groups, interview transcripts), conducted in any geographic location, where experiences are presented from the child's perspective. Studies assessing children's experiences of cancer, other chemotherapy-related side effects, or the parent's personal experience will be excluded.

METHODS

A search of MEDLINE, Embase, PsycINFO, and CINAHL databases will be conducted. Full-text, English-only articles employing a qualitative research methodology will be included in the screening process. Two independent reviewers will retrieve and screen full-text studies, and assess methodological quality of the included studies. Meta-aggregation will be performed and a ConQual Summary of Findings will present the confidence in the findings.

SYSTEMATIC REVIEW REGISTRATION NUMBER

PROSPERO CRD42021240573.

Neuroimmune reactivity marker expression in rodent models of chemotherapy-induced cognitive impairment: A systematic scoping review

BACKGROUND

Chemotherapy-induced cognitive impairment (CICI) is a debilitating side effect arising from chemotherapy treatments. The condition is characterised by a range of cognitive deficits including impairment to memory, attention, and concentration. Whilst the underlying mechanisms that contribute to CICI remain unclear, neuroinflammation has been suggested as one key contributor.

METHOD

A comprehensive systematic search of EMBASE and Medline via PubMed was conducted to identify studies on neuroimmune reactivity marker expression changes and resulting cognitive changes in preclinical rodent models of CICI.

RESULTS

A total of twenty studies met the eligibility criteria and were included in the scoping review. There was significant heterogeneity in the methodology employed in the included studies. Our findings demonstrate that widespread changes in cytokines, chemokines, microglia reactivity, and astrocyte reactivity are observed in CICI in the brain regions expected to be affected, given the nature of the cognitive impairment observed in CICI.

CONCLUSIONS

Although there was considerable heterogeneity in study design that made comparisons between studies difficult, our findings suggest that neuroinflammation commonly occurs in CICI preclinical rodent models and shows an association with cognitive impairment.

Longitudinal investigation of cognitive deficits in breast cancer patients and their gray matter correlates: impact of education level

Cognitive deficits are a major complaint in breast cancer patients, even before chemotherapy. Comprehension of the cerebral mechanisms related to cognitive impairment in breast cancer patients remains difficult due to the scarcity of studies investigating both cognitive and anatomical imaging changes. Furthermore, only some of the patients experienced cognitive decline following chemotherapy, yet few studies have identified risk factors for cognitive deficits in these patients. It has been shown that education level could impact cognitive abilities during the recovery phase following chemotherapy. Our main aim was to longitudinally evaluate cognitive and anatomical changes associated with cancer and chemotherapy in breast cancer patients. Our secondary aim was to assess the impact of education level on cognitive performances and gray matter (GM) atrophy in these patients. Twenty patients were included before chemotherapy (T1), 1 month (T2) and 1 year (T3) after chemotherapy. Twenty-seven controls without a history of cancer were assessed at T1 and T3 only. Cluster groups based on education level were defined for both groups and were further compared. Comparison between patients and controls revealed deficits in patients on verbal episodic memory retrieval at T1 and T3 and on executive functions at T3. After chemotherapy, breast cancer patients had GM atrophy that persisted or recovered 1 year after chemotherapy depending on the cortical areas. Increase in GM volumes from T1 to T3 were also found in both groups. At T2, patients with a higher level of education compared to lower level exhibited higher episodic memory retrieval and state anxiety scores, both correlating with cerebellar volume. This higher level of education group exhibited hippocampal atrophy. Our results suggest that, before chemotherapy, cancer-related processes impact cognitive functioning and that this impact seems exacerbated by the effect of chemotherapy on certain brain regions. Increase in GM volumes after chemotherapy were unexpected and warrant further investigations. Higher education level was associated, 1 month after the end of chemotherapy, with greater anxiety and hippocampal atrophy despite a lack of cognitive deficits. These results suggest, for the first time, the occurrence of compensation mechanisms that may be linked to cognitive reserve in relationship to state anxiety. This identification of factors, which may compensate cognitive impairment following chemotherapy, is critical for patient care and quality of life.

Therapies for cognitive impairment in breast cancer survivors treated with chemotherapy: A protocol for systematic review

OBJECTIVE

The aim of this systematic review was to evaluate the effect of therapies for cognitive impairment on patients' perceived cognitive function in breast cancer survivors with chemotherapy-related cognitive impairment.

METHOD

A literature search of PubMed, Embase, and the Cochrane Library was conducted up to April 2019. Search terms included breast cancer, chemotherapy, and cognitive impairment.

RESULT

Six randomized controlled trials with a total of 305 patients were included in this review. A total of 6 randomized controlled trials using various treatments (Tibetan sound meditation, donepezil, memory and attention adaptation training, aerobic exercise, acupuncture, Qigong) for chemotherapy-related cognitive impairment met the eligibility criteria and were included. This review showed that meditative interventions (Tibetan sound meditation, Qigong) and cognitive therapy (memory and attention adaptation training) may partially improve some aspects of patients' perceived (self-reported) cognitive functioning, particularly patients' perceived cognitive impairment and ability.

CONCLUSION

In this systematic review, the results showed that meditative interventions (Tibetan sound meditation, Qigong) and cognitive therapy (memory and attention adaptation training) may be optional therapies. We hope to have more randomized controlled trials to support this result in the future.

An Evaluation of DNA Methyltransferase 1 (DNMT1) Single Nucleotide Polymorphisms and Chemotherapy-Associated Cognitive Impairment: A Prospective, Longitudinal Study

Strong evidence suggests that genetic variations in DNA methyltransferases (DNMTs) may alter the downstream expression and DNA methylation patterns of neuronal genes and influence cognition. This study investigates the association between a DNMT1 polymorphism, rs2162560, and chemotherapy-associated cognitive impairment (CACI) in a cohort of breast cancer patients. This is a prospective, longitudinal cohort study. From 2011 to 2017, 351 early-stage breast cancer patients receiving chemotherapy were assessed at baseline, the midpoint, and the end of chemotherapy. DNA was extracted from whole blood, and genotyping was performed using Sanger sequencing. Patients' self-perceived cognitive function and cognitive performance were assessed at three different time points using FACT-Cog (v.3) and a neuropsychological battery, respectively. The association between DNMT1 rs2162560 and cognitive function was evaluated using logistic regression analyses. Overall, 33.3% of the patients reported impairment relative to baseline in one or more cognitive domains. Cognitive impairment was observed in various objective cognitive domains, with incidences ranging from 7.2% to 36.9%. The DNMT1 rs2162560 A allele was observed in 21.8% of patients and this was associated with lower odds of self-reported cognitive decline in the concentration (OR = 0.45, 95% CI: 0.25-0.82, P = 0.01) and functional interference (OR = 0.48, 95% CI: 0.24-0.95, P = 0.03) domains. No significant association was observed between DNMT1 rs2162560 and objective cognitive impairment. This is the first study to show a significant association between the DNMT1 rs2162560 polymorphism and CACI. Our data suggest that epigenetic processes could contribute to CACI, and further studies are needed to validate these findings.

Breast cancer treatment and its effects on aging

Breast cancer is the most common cancer of women in the United States. It is also proving to be one of the most treatable. Early detection, surgical intervention, therapeutic radiation, cytotoxic chemotherapies and molecularly targeted agents are transforming the lives of patients with breast cancer, markedly improving their survival. Although current breast cancer treatments are largely successful in producing cancer remission and extending lifespan, there is concern that these treatments may have long lasting detrimental effects on cancer survivors, in part, through their impact on non-tumor cells. Presently, the impact of breast cancer treatment on normal cells, its impact on cellular function and its effect on the overall function of the individual are incompletely understood. In particular, it is unclear whether breast cancer and/or its treatments are associated with an accelerated aging phenotype. In this review, we consider breast cancer survivorship from the perspective of accelerated aging, and discuss the evidence suggesting that women treated for breast cancer may suffer from an increased rate of physical and cognitive decline that likely corresponds with underlying vulnerabilities of genome instability, epigenetic changes, and cellular senescence.

Association of functional dorsal attention network alterations with breast cancer and chemotherapy

Breast cancer is the most common cancer among women worldwide. Adjuvant chemotherapy has significantly reduced mortality but increased cognitive impairments, including attention function, making quality of life issues a crucial concern. This study enrolled nineteen breast cancer patients who were treated with standard chemotherapy within 6 months and 20 sex-matched healthy controls to investigate the brain effects of chemotherapy. All participants underwent resting-state functional magnetic resonance imaging (rs-fMRI) with mean fractional amplitude of low-frequency fluctuation (mfALFF) analysis and were correlated with neuropsychological tests, including the Mini-Mental State Examination (MMSE), the Cognitive and Affective Mindfulness Scale-Revised (CAMS-R), and the Impact of Event Scale-Revised (IES-R), to explore the possible underlying mechanism of cognitive alternations. We found increased mfALFF over the frontoparietal lobe and decreased mfALFF over the occipital lobe in the cancer patients compared with the healthy controls; the altered brain regions may be associated with the dorsal attention network (DAN) and may be explained by a compensatory mechanism. Both MMSE and CAMS-R scores showed a positive correlation with mfALFF in the occipital lobe but a negative correlation in the frontoparietal lobe. By contrast, IES-R scores showed a positive correlation with mfALFF in the frontoparietal lobe but a negative correlation in the occipital lobe. These alterations are potentially related to the effects of both chemotherapy and psychological distress. Future research involving a larger sample size of patients with breast cancer is recommended.

Relationships between self-reported sleep quality components and cognitive functioning in breast cancer survivors up to 10 years following chemotherapy

OBJECTIVE

Links have been made between aspects of sleep quality and cognitive function in breast cancer survivors (BCS), but findings are heterogeneous. The objective of this study is to examine relationships between specific sleep quality components (latency, duration, efficiency, daytime sleepiness, sleep disturbance, use of sleep aids) and cognitive impairment (performance and perceived), and determine which sleep quality components are the most significant contributors to cognitive impairments in BCS 6 months to 10 years post chemotherapy.

METHODS

Women 21 to 65 years old with a history of non-metastatic breast cancer following chemotherapy completion were recruited. Data collection included surveys to evaluate sleep quality and perceived cognitive impairments, and neuropsychological testing to evaluate verbal fluency and memory. Descriptive statistics, bivariate correlations, and hierarchical multiple regression were calculated.

RESULTS

Ninety women (mean age 49) completed data collection. Moderate significant correlations were found between daytime dysfunction, sleep efficiency, sleep latency, and sleep disturbance and perceived cognitive impairment (Rs = -0.37 to -0.49, Ps < .00049), but not objective cognitive performance of verbal fluency, memory, or attention. After accounting for individual and clinical characteristics, the strongest predictors of perceived cognitive impairments were daytime dysfunction, sleep efficiency, and sleep disturbance.

CONCLUSIONS

Findings support links between sleep quality and perceived cognitive impairments in BCS and suggest specific components of sleep quality (daytime dysfunction, sleep efficiency, and sleep disturbance) are associated with perceived cognitive functioning in this population. Findings can assist clinicians in guiding survivors to manage sleep and cognitive problems and aid in the design of interventional research.

Identifying cytokine predictors of cognitive functioning in breast cancer survivors up to 10 years post chemotherapy using machine learning

INTRODUCTION

The purpose of this study is to explore 13 cytokine predictors of chemotherapy-related cognitive impairment (CRCI) in breast cancer survivors (BCS) 6 months to 10 years after chemotherapy completion using a multivariate, non-parametric approach.

METHODS

Cross sectional data collection included completion of a survey, cognitive testing, and non-fasting blood from 66 participants. Data were analyzed using random forest regression to identify the most significant predictors for each of the cognitive test scores.

RESULTS

A different cytokine profile predicted each cognitive test. Adjusted R² for each model ranged from 0.71-0.77 (p's < 9.50^-10). The relationships between all the cytokine predictors and cognitive test scores were non-linear.

CONCLUSIONS

Our findings are unique to the field of CRCI and suggest non-linear cytokine specificity to neural networks underlying cognitive functions assessed in this study.

Randomized controlled trial of increasing physical activity on objectively measured and self-reported cognitive functioning among breast cancer survivors: The memory & motion study

BACKGROUND

Increasing physical activity can improve cognition in healthy and cognitively impaired adults; however, the benefits for cancer survivors are unknown. The current study examined a 12-week physical activity intervention, compared with a control condition, on objective and self-reported cognition among breast cancer survivors.

METHODS

Sedentary breast cancer survivors were randomized to an exercise arm (n = 43) or a control arm (n = 44). At baseline and at 12 weeks, objective cognition was measured with the National Institutes of Health Cognitive Toolbox, and self-reported cognition using the Patient-Reported Outcomes Measurement Information System scales. Linear mixed-effects regression models tested intervention effects for changes in cognition scores.

RESULTS

On average, participants (n = 87) were aged 57 years (standard deviation, 10.4 years) and were 2.5 years (standard deviation, 1.3 years) post surgery. Scores on the Oral Symbol Digit subscale (a measure of processing speed) evidenced differential improvement in the exercise arm versus the control arm (b = 2.01; P < .05). The between-group differences in improvement on self-reported cognition were not statistically significant but were suggestive of potential group differences. Time since surgery moderated the correlation, and participants who were ≤2 years post surgery had a significantly greater improvement in Oral Symbol Digit score (exercise vs control (b = 4.00; P < .01), but no significant improvement was observed in patients who were >2 years postsurgery (b = -1.19; P = .40). A significant dose response was observed with greater increased physical activity associated with objective and self-reported cognition in the exercise arm.

CONCLUSIONS

The exercise intervention significantly improved processing speed, but only among those who had been diagnosed with breast cancer within the past 2 years. Slowed processing speed can have substantial implications for independent functioning, supporting the potential importance of early implementation of an exercise intervention among patients with breast cancer. Cancer 2018;124:192-202. © 2017 American Cancer Society.

Impact of increasing physical activity on cognitive functioning in breast cancer survivors: Rationale and study design of Memory & Motion

INTRODUCTION

Many breast cancer survivors experience problems with cognitive functioning that can persist years after treatment. Increasing physical activity has been shown to improve cognitive functioning in healthy and cognitively impaired adults, but has not yet been tested in cancer survivors. The primary aim of this randomized controlled trial is to examine the effects of a 3-month physical activity intervention compared to a waitlist Control arm on neuropsychological outcomes and subjective cognitive concerns in breast cancer survivors.

METHODS

Eighty sedentary breast cancer survivors, self-reporting difficulties with cognition, will be randomized into an Exercise arm or Control arm. The Exercise arm includes an activity tracker (i.e., a Fitbit), phone calls, plus tailored and non-tailored email content. The Control arm will receive emails on women's health topics on the same schedule as the Exercise arm. Assessments conducted at baseline and 3 months include: neuropsychological testing, cognitive concerns and other aspects of quality of life, and 7 days of a hip-worn accelerometer. Participants will also provide fasting blood draws to assess brain-derived neurotropic factor, Insulin-like growth factor 1, insulin resistance, and C-reactive protein. Primary and secondary outcomes are changes in neuropsychological testing and cognitive concerns. Biomarkers will be examined to further understand the underlying relationship between physical activity and cognition.

CONCLUSION

The Memory & Motion study is designed to test whether increasing physical activity can improve cognitive functioning in breast cancer survivors. Results from this study could be used to guide development of interventions to improve cognitive functioning in breast cancer survivors.

Brain-derived neurotrophic factor genetic polymorphism (rs6265) is protective against chemotherapy-associated cognitive impairment in patients with early-stage breast cancer

Background

Brain-derived neurotrophic factor (BDNF), a neurotrophin that regulates neuronal function and development, is implicated in several neurodegenerative conditions. Preliminary data suggest that a reduction of BDNF concentrations may lead to postchemotherapy cognitive impairment. We hypothesized that a single nucleotide polymorphism (rs6265) of the BDNF gene may predispose patients to cognitive impairment. This study aimed to evaluate the effect of BDNF gene polymorphism on chemotherapy-associated cognitive impairment.

Methods

Overall, 145 patients receiving chemotherapy for early-stage breast cancer (mean age: 50.8 ± 8.8 y; 82.1% Chinese) were recruited. Patients' cognitive functions were assessed longitudinally using the validated Functional Assessment of Cancer Therapy–Cognitive Function (v.3) and an objective computerized tool, Headminder. Genotyping was performed using Sanger sequencing. Logistic regression was used to evaluate the association between BDNF Val66Met polymorphism and cognition after adjusting for ethnicity and clinically important covariates.

Results

Of the 145 patients, 54 (37%) reported cognitive impairment postchemotherapy. The Met/Met genotype was associated with statistically significant lower odds of developing cognitive impairment (odds ratio [OR] = 0.26; 95% CI: 0.08–0.92; P = .036). The Met carriers were less likely to experience impairment in the domains of verbal fluency (OR = 0.34; 95% CI: 0.12–0.90; P = .031) and multitasking ability (OR = 0.37; 95% CI: 0.15–0.91; P = .030) compared with the Val/Val homozygote. No associations were observed between Headminder and the BDNF Val66Met polymorphism.

Conclusions

This is the first study to provide evidence that carriers of the BDNF Met allele are protected against chemotherapy-associated cognitive impairment. Further studies are required to validate the findings.

Cytotoxic chemotherapy increases sleep and sleep fragmentation in non-tumor-bearing mice

Sleep disruption ranks among the most common complaints of breast cancer patients undergoing chemotherapy. Because of the complex interactions among cancer, treatment regimens, and life-history traits, studies to establish a causal link between chemotherapy and sleep disruption are uncommon. To investigate how chemotherapy acutely influences sleep, adult female c57bl/6 mice were ovariectomized and implanted with wireless biotelemetry units. EEG/EMG biopotentials were collected over the course of 3days pre- and post-injection of 13.5mg/kg doxorubicin and 135mg/kg cyclophosphamide or the vehicle. We predicted that cyclophosphamide+doxorubicin would disrupt sleep and increase central proinflammatory cytokine expression in brain areas that govern vigilance states (i.e., hypothalamus and brainstem). The results largely support these predictions; a single chemotherapy injection increased NREM and REM sleep during subsequent active (dark) phases; this induced sleep was fragmented and of low quality. Mice displayed marked increases in low theta (5-7Hz) to high theta (7-10Hz) ratios following chemotherapy treatment, indicating elevated sleep propensity. The effect was strongest during the first dark phase following injection, but mice displayed disrupted sleep for the entire 3-day duration of post-injection sleep recording. Vigilance state timing was not influenced by treatment, suggesting that acute chemotherapy administration alters sleep homeostasis without altering sleep timing. qPCR analysis revealed that disrupted sleep was accompanied by increased IL-6 mRNA expression in the hypothalamus. Together, these data implicate neuroinflammation as a potential contributor to sleep disruption after chemotherapy.

Objectively measured physical activity and cognitive functioning in breast cancer survivors

PURPOSE

This study aimed to explore the relationship between objectively measured physical activity and cognitive functioning in breast cancer survivors.

METHODS

Participants were 136 postmenopausal breast cancer survivors. Cognitive functioning was assessed using a comprehensive computerized neuropsychological test. Seven-day physical activity was assessed using hip-worn accelerometers. Linear regression models examined associations of minutes per day of physical activity at various intensities on individual cognitive functioning domains. The partially adjusted model controlled for primary confounders (model 1), and subsequent adjustments were made for chemotherapy history (model 2) and body mass index (BMI) (model 3). Interaction and stratified models examined BMI as an effect modifier.

RESULTS

Moderate-to-vigorous physical activity (MVPA) was associated with information processing speed. Specifically, 10 min of MVPA was associated with a 1.35-point higher score (out of 100) on the information processing speed domain in the partially adjusted model and a 1.29-point higher score when chemotherapy was added to the model (both p < 0.05). There was a significant BMI × MVPA interaction (p = 0.051). In models stratified by BMI (<25 vs. ≥25 kg/m(2)), the favorable association between MVPA and information processing speed was stronger in the subsample of overweight and obese women (p < 0.05) but not statistically significant in the leaner subsample. Light-intensity physical activity was not significantly associated with any of the measured domains of cognitive function.

CONCLUSIONS

MVPA may have favorable effects on information processing speed in breast cancer survivors, particularly among overweight or obese women.

IMPLICATIONS FOR CANCER SURVIVORS

Interventions targeting increased physical activity may enhance aspects of cognitive function among breast cancer survivors.

Association of proinflammatory cytokines and chemotherapy-associated cognitive impairment in breast cancer patients: a multi-centered, prospective, cohort study

BACKGROUND

Existing evidence suggests that proinflammatory cytokines play an intermediary role in postchemotherapy cognitive impairment. This is one of the largest multicentered, cohort studies conducted in Singapore to evaluate the prevalence and proinflammatory biomarkers associated with cognitive impairment in breast cancer patients.

PATIENTS AND METHODS

Chemotherapy-receiving breast cancer patients (stages I-III) were recruited. Proinflammatory plasma cytokines concentrations [interleukin (IL)-1β, IL-2, IL-4, IL-6, IL-8, IL-10, granulocyte-macrophage colony-stimulating factor, interferon-γ and tumor necrosis factor-α] were evaluated at 3 time points (before chemotherapy, 6 and 12 weeks after chemotherapy initiation). The FACT-Cog (version 3) was utilized to evaluate patients' self-perceived cognitive disturbances and a computerized neuropsychological assessment (Headminder) was administered to evaluate patients' memory, attention, response speed and processing speed. Changes of cognition throughout chemotherapy treatment were compared against the baseline. Linear mixed-effects models were applied to test the relationships of clinical variables and cytokine concentrations on self-perceived cognitive disturbances and each objective cognitive domain.

RESULTS

Ninety-nine patients were included (age 50.5 ± 8.4 years; 81.8% Chinese; mean duration of education = 10.8 ± 3.3 years). Higher plasma IL-1β was associated with poorer response speed performance (estimate: -0.78; 95% confidence interval (CI) -1.34 to -0.03; P = 0.023), and a higher concentration of IL-4 was associated with better response speed performance (P = 0.022). Higher concentrations of IL-1β and IL-6 were associated with more severe self-perceived cognitive disturbances (P = 0.018 and 0.001, respectively). Patients with higher concentrations of IL-4 also reported less severe cognitive disturbances (P = 0.022).

CONCLUSIONS

While elevated concentrations of IL-6 and IL-1β were observed in patients with poorer response speed performance and perceived cognitive disturbances, IL-4 may be protective against chemotherapy-associated cognitive impairment. This study is important because cytokines would potentially be mechanistic mediators of chemotherapy-associated cognitive changes.

Clinical characteristics, pathophysiology, and management of noncentral nervous system cancer-related cognitive impairment in adults

Answer questions and earn CME/CNE Over the past few decades, a body of research has emerged confirming what many adult patients with noncentral nervous system cancer have long reported-that cancer and its treatment are frequently associated with cancer-related cognitive impairment (CRCI). The severity of CRCI varies, and symptoms can emerge early or late in the disease course. Nonetheless, CRCI is typically mild to moderate in nature and primarily involves the domains of memory, attention, executive functioning, and processing speed. Animal models and novel neuroimaging techniques have begun to unravel the pathophysiologic mechanisms underlying CRCI, including the role of inflammatory cascades, direct neurotoxic effects, damage to progenitor cells, white matter abnormalities, and reduced functional connectivity, among others. Given the paucity of research on CRCI with other cancer populations, this review synthesizes the current literature with a deliberate focus on CRCI within the context of breast cancer. A hypothetical case-study approach is used to illustrate how CRCI often presents clinically and how current science can inform practice. While the literature regarding intervention for CRCI is nascent, behavioral and pharmacologic approaches are discussed.

The genetic variants underlying breast cancer treatment-induced chronic and late toxicities: a systematic review

A systematic review was performed to describe the findings from 19 genetic association studies that have examined the genetic variants underlying four common treatment-induced chronic and late toxicities in breast cancer patients, and to evaluate the quality of reporting. Three out of 5 studies found an association between HER2 lle655Val polymorphisms and trastuzumab-induced cardiotoxicity. Two studies found a positive association between cognitive impairment and the Val allele of the COMT gene and the ε4 allele of the apolipoprotein E gene. Genetic associations were established between fatigue and the G/G genotype of IL6-174 and TNF-308, and the Met allele of the COMT gene in 4 studies. Among studies (N=8) that evaluated the genetic associations underlying peripheral neuropathy, CYP2C8∗3 variant is commonly reported as the associated gene. Most studies failed to conform to the major criteria listed in the STREGA guidelines, with a lack of transparent reporting of methods and results.

Chemobrain experienced by breast cancer survivors: a meta-ethnography study investigating research and care implications

BACKGROUND

Cognitive impairment, colloquially termed "chemobrain", occurs in 10-40% of all cancer patients, and is an emerging target of cancer survivorship research.

AIM

This study reviews published qualitative studies to explore cognitive impairments or chemobrain among breast cancer survivors, with particular attention given to the impact on quality of life.

METHOD

Using keywords, we searched ten electronic databases (CINAHL, EMBASE, Proquest, OVID SP, MEDLINE, Oxford Journal, Science Direct, PubMED).

FINDINGS

Of 457 papers, seven relevant papers were included. Data was extracted and concepts were analysed using a meta ethnography approach. Four second order intepretations were identified, on the basis of which, four third order intrepretations were constructed. Linked together in a line of argument, was a consistent account on their struggles to self-manage the chemobrain impairments that impact their daily lives. Five concepts emerged from the analysis of the primary findings: i) real experiences of cognitive changes, ii) calls for help, iii) impact of cognitive impairments, iv) coping and v) survivorship and meaning. Further synthesis resulted in four new order intepretations: i) The chemobrain struggle, ii) The substantial impact of chemobrain on life domains, iii) The struggle to readjust and to self manage, and iv) 'thankful yet fearful' representation.

DISCUSSION

Awareness of cognitive changes were context-dependent on healthcare settings and cultural contexts as strong determinants. Subjects verified the existence of chemobrain but healthcare providers mis-recognised, under-recognised, and sometimes negated it perhaps due to its unknown aetiology. Asian breast cancer survivors appear less vocal than their western counterparts.

CONCLUSION

The current literature on the lived experiences of how women experienced chemobrain provides a consistent report that chemobrain is real, persistent and with detrimental impacts on quality of life - manifested as a constant struggles. A greater awareness of the effects of chemobrain with improved functional assessment and interventions is warranted.

The effects of virgin coconut oil (VCO) as supplementation on quality of life (QOL) among breast cancer patients

BACKGROUND

Breast cancer is the most common cancer amongst Malaysian women. Both the disease and its treatment can disrupt the lives of the woman and adversely affect all aspects of life and thus can alter a woman's quality of life. The aim of this study was to examine the effect of virgin coconut oil (VCO) on the quality of life (QOL) of patients diagnosed with breast cancer.

METHODS

This was a prospective study of breast cancer patients admitted into the Oncology Unit of Hospital Universiti Sains Malaysia, Kubang Kerian, Kelantan, Malaysia. The sample consisted of 60 patients with stage III and IV breast cancer allocated to either an intervention group (n = 30) or a control group (n = 30) using a simple random table. QOL was evaluated from the first cycle of chemotherapy to the sixth cycle, and data were collected using a validated Bahasa Malaysia version of the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire Breast Cancer Module (EORTC QLQ-C30) and its breast-specific module (QLQ-BR 23).

RESULTS

The mean age of breast cancer patients was 50.2 (SD = 13.5) years. There were significant mean score differences for functioning and global QOL between groups (α < 0.01). The intervention group also had better scores for symptoms including fatigue, dyspnea, sleep difficulties, and loss of appetite compared to the control group. Although there are deteriorations for sexual enjoyment, the intervention group exhibited improvement in breast functioning and symptom scores for body image, sexual function, future perspective, breast symptoms, and systemic therapy side effects.

CONCLUSION

VCO consumption during chemotherapy helped improve the functional status and global QOL of breast cancer patients. In addition, it reduced the symptoms related to side effects of chemotherapy.

Elevated prefrontal myo-inositol and choline following breast cancer chemotherapy

Breast cancer survivors are at increased risk for cognitive dysfunction, which reduces quality of life. Neuroimaging studies provide critical insights regarding the mechanisms underlying these cognitive deficits as well as potential biologic targets for interventions. We measured several metabolite concentrations using (1)H magnetic resonance spectroscopy as well as cognitive performance in 19 female breast cancer survivors and 17 age-matched female controls. Women with breast cancer were all treated with chemotherapy. Results indicated significantly increased choline (Cho) and myo-inositol (mI) with correspondingly decreased N-acetylaspartate (NAA)/Cho and NAA/mI ratios in the breast cancer group compared to controls. The breast cancer group reported reduced executive function and memory, and subjective memory ability was correlated with mI and Cho levels in both groups. These findings provide preliminary evidence of an altered metabolic profile that increases our understanding of neurobiologic status post-breast cancer and chemotherapy.

Lifestyle factors associated with cognitive functioning in breast cancer survivors

OBJECTIVE

Weight, physical activity, and sleep are modifiable lifestyle factors that impact cognitive functioning in noncancer populations but have yet to be examined in cancer survivors. The aim of the study was to assess the relationship of obesity, physical activity, and sleep, with cognitive functioning among breast cancer survivors.

METHODS

Participants were 136 early-stage postmenopausal breast cancer survivors who completed an assessment of neuropsychological testing, height, weight, physical activity, and sleep. Linear regression models examined the associations of the seven neuropsychological domains with obesity, physical activity, and sleep. Logistic regression models examined odd of impairment in each domain. All models controlled for breast cancer treatment variables and relevant demographic and clinical variables.

RESULTS

Obese participants had significantly worse performance (β = -5.04, standard error (SE) = 2.53) and were almost three times more likely to be impaired (odds ratio (OR) = 2.87; 95% CI: 1.02-8.10) on the Information processing domain. The highest tertile of physical activity was significantly related to better performance on the executive functioning domain (β = 5.13, SE = 2.42) and attention domain (β = 4.26, SE = 2.07). The middle tertile of physical activity was significantly related to better performance (β = 9.00, SE = 3.09) and decreased odds of impairment (OR = 0.89, 95% CI: 0.07-0.91) on the visual-spatial domain. More hours of sleep per night was significantly associated with better performance (β = 2.69, SE = 0.98) and decreased odds of impairment (OR = 0.52; 95% CI: 0.33-0.82) on the verbal functioning domain.

CONCLUSIONS

These findings suggest that obesity, physical activity, and sleep are related to cognitive functioning among breast cancer survivors and have potential to be intervention targets to improve cognitive functioning.

Multivariate pattern analysis of FMRI in breast cancer survivors and healthy women

Advances in breast cancer (BC) treatments have resulted in significantly improved survival rates. However, BC chemotherapy is often associated with several side effects including cognitive dysfunction. We applied multivariate pattern analysis (MVPA) to functional magnetic resonance imaging (fMRI) to find a brain connectivity pattern that accurately and automatically distinguishes chemotherapy-treated (C+) from non-chemotherapy treated (C-) BC females and healthy female controls (HC). Twenty-seven C+, 29 C-, and 30 HC underwent fMRI during an executive-prefrontal task (Go/Nogo). The pattern of functional connectivity associated with this task discriminated with significant accuracy between C+ and HC groups (72%, p = .006) and between C+ and C- groups (71%, p = .012). However, the accuracy of discrimination between C- and HC was not significant (51%, p = .46). Compared with HC, behavioral performance of the C+ and C- groups during the task was intact. However, the C+ group demonstrated altered functional connectivity in the right frontoparietal and left supplementary motor area networks compared to HC, and in the right middle frontal and left superior frontal gyri networks, compared to C-. Our results provide further evidence that executive function performance may be preserved in some chemotherapy-treated BC survivors through recruitment of additional neural connections.

Cytokines as mediators of chemotherapy-associated cognitive changes: current evidence, limitations and directions for future research

Objectives

While various clinical and pharmacological determinants for chemotherapy-associated cognitive impairment have been identified, conflicting evidence suggests that cytokines might play an intermediary role. The objective of this systematic review was to evaluate the current evidence pertaining to the associations among chemotherapy, cytokines induction and cognitive impairment in cancer patients.

Methods

A literature search with PubMed and SciVerse Scopus was conducted in March 2013 to gather relevant articles and abstracts that fulfilled the inclusion and exclusion criteria. This review included studies that had performed objective and/or subjective cognitive assessments and cytokine measurements on defined populations of cancer patients who received chemotherapy.

Results

High methodological heterogeneity existed among the selected studies which differed in cancer populations, subject characteristics, cognitive endpoints, types of cytokines tested and their measurement methods. Weak to moderate correlations were observed between IL-1β, IL-6, TNF-α levels, and different degrees of cognitive impairment. Different types of chemotherapy treatments might lead to varying presentations and severities of cytokine-induced cognitive impairment. Notably, the time concordance between the onset of cytokine induction and occurrence of cognitive impairment was not well elucidated. A number of confounding factors was identified to interfere with the expression levels of cytokines; these confounders included subjects' cancer types, ages, genders, genetics and psychosocial characteristics such as anxiety, depression and fatigue.

Conclusion

Although existing studies observed cognitive impairment and cytokine dysregulation in patients who receive chemotherapy, our results suggest that the intermediary role of cytokines in post-chemotherapy cognitive impairment is still controversial and requires further evaluation. A list of methodological recommendations is proposed to harmonize future studies of this subject matter.

A randomized trial of cognitive rehabilitation in cancer survivors

AIMS

The second most frequently reported post-treatment symptom in cancer survivors are concerns about impaired cognition. Despite numerous studies demonstrating significant impairments in a portion of survivors, information on effective treatments remains an emerging area of research. This study examined the effectiveness of a group-based cognitive rehabilitation intervention in cancer survivors.

MAIN METHODS

This study was a randomized, controlled study of a 7-week cognitive rehabilitation intervention delivered in group format. Participants were evaluated with subjective symptom questionnaires and objective neurocognitive tests prior to and following treatment.

KEY FINDINGS

Twenty-eight participants (mean age 58 years) with a median of 3 years (± 6 years) post-primary/adjuvant treatment and various cancer sites (breast, bladder, prostate, colon, uterine) completed the study. Compared to baseline, the treatment group demonstrated improvements in symptoms of perceived cognitive impairments (p<.01), cognitive abilities (p<.01) and overall quality of life with regard to cognitive symptoms (p<.01) as measured by the FACT-Cog. The treatment group also improved on objective measures of attention (p<.05) and a trend toward improvement on verbal memory. Significant improvement was not observed on all cognitive tests.

SIGNIFICANCE

A group based cognitive rehabilitation intervention in cancer survivors was effective for improving attention abilities and overall quality of life related to cognition. Results suggest that group based cognitive rehabilitation may be an effective intervention for treating cognitive dysfunction in cancer patients and should be further studied in a larger trial with an active control condition.

Psychometric properties and measurement equivalence of the English and Chinese versions of the functional assessment of cancer therapy-cognitive in Asian patients with breast cancer

OBJECTIVE

This study was designed to examine the psychometric properties and measurement equivalence of the English and Chinese versions of the Functional Assessment of Cancer Therapy-Cognitive Function (Version 3) (FACT-Cog) in multiethnic Asian patients with breast cancer.

METHODS

This prospective study involved patients with breast cancer from the National Cancer Centre Singapore. The concurrent validity of the FACT-Cog was assessed according to its strength of correlation with the validated European Organization for Research and Treatment of Cancer Quality of Life Core Questionnaire 30 cognitive functioning scale, and its association with fatigue, global health status, and anxiety. The known-group validity was assessed on the basis of receipt of chemotherapy. Factor analysis was conducted to ascertain the one-factor structure of each cognitive domain. The reliability was evaluated by using Cronbach's alpha and intraclass correlation coefficient within the cognitive domains. Multiple regression analyses were performed to compare the total scores between the two language versions, adjusting for covariates.

RESULTS

A total of 185 English-speaking and 143 Chinese-speaking patients were recruited. Both the English and Chinese FACT-Cog total scores correlated strongly with the European Organization for Research and Treatment of Cancer Quality of Life Core Questionnaire 30 cognitive functioning scale scores (r = 0.725 and 0.646), whereas correlations with fatigue, anxiety, and global health status were weak to moderate (|r| = 0.376-0.589). Regarding the known-group validity, more severe perceived cognitive disturbance was observed among patients receiving chemotherapy than among those who were not for both versions (P = .010 and .008, respectively). Internal consistencies within the cognitive domains were high (Cronbach's α 0.707-0.929), and test-retest reliability was satisfactory for both versions (intraclass correlation coefficient 0.762 and 0.697). The measurement equivalence between the English and Chinese versions was established for all domains except the multitasking domain.

CONCLUSION

The English and Chinese versions of the FACT-Cog are valid, reliable, and equivalent for clinical and research use.

Vascular endothelial growth factor inhibitors and cognitive impairment: evidence and controversies

INTRODUCTION

Chemotherapy-induced cognitive impairment, or 'chemobrain,' has been well established in the literature. However, neurocognitive toxic effect induced by targeted therapies such as anti-angiogenic agents is poorly investigated. Recently, emerging evidence suggests vascular endothelial growth factor (VEGF) to have a possible role in brain cognition giving rise to concerns whether VEGF inhibitors (VEGFIs) may induce neurotoxic effect on cancer patients' cognitive function.

AREAS COVERED

The aim of this review was to evaluate the plausible mechanisms underlying VEGF and cognition, and to highlight the evidence and controversies surrounding the cognitive issues associated with the use of VEGFIs.

EXPERT OPINION

This review paper has brought attention to the potential cognitive issues associated with the use of VEGFIs and has added a new, unexplored dimension to the problem of cancer treatment-related cognitive changes. However, the lack of evidence warrants the need for more well-designed studies to quantify the prevalence and severity of VEGFI-induced cognitive impairment in the cancer population, and to establish the role of VEGF in human cognitive function.

Default mode network connectivity distinguishes chemotherapy-treated breast cancer survivors from controls

Breast cancer (BC) chemotherapy is associated with cognitive changes including persistent deficits in some individuals. We tested the accuracy of default mode network (DMN) resting state functional connectivity patterns in discriminating chemotherapy treated (C+) from non-chemotherapy (C-) treated BC survivors and healthy controls (HC). We also examined the relationship between DMN connectivity patterns and cognitive function. Multivariate pattern analysis was used to classify 30 C+, 27 C-, and 24 HC, which showed significant accuracy for discriminating C+ from C- (91.23%, P < 0.0001) and C+ from HC (90.74%, P < 0.0001). The C- group did not differ significantly from HC (47.06%, P = 0.60). Lower subjective memory function was correlated (P < 0.002) with greater hyperplane distance (distance from the linear decision function that optimally separates the groups). Disrupted DMN connectivity may help explain long-term cognitive difficulties following BC chemotherapy.

Cognitive training for improving executive function in chemotherapy-treated breast cancer survivors

BACKGROUND

A majority of breast cancer (BC) survivors, particularly those treated with chemotherapy, experience long-term cognitive deficits that significantly reduce quality of life. Among the cognitive domains most commonly affected include executive functions (EF), such as working memory, cognitive flexibility, multitasking, planning, and attention. Previous studies in other populations have shown that cognitive training, a behavioral method for treating cognitive deficits, can result in significant improvements in a number of cognitive skills, including EF.

MATERIALS AND METHODS

In this study, we conducted a randomized controlled trial to investigate the feasibility and preliminary effectiveness of a novel, online EF training program in long-term BC survivors. A total of 41 BC survivors (21 active, 20 wait list) completed the 48 session training program over 12 weeks. The participants were, on average, 6 years after therapy.

RESULTS

Cognitive training led to significant improvements in cognitive flexibility, verbal fluency and processing speed, with marginally significant downstream improvements in verbal memory as assessed via standardized measures. Self-ratings of EF skills, including planning, organizing, and task monitoring, also were improved in the active group compared with the wait list group.

CONCLUSIONS

Our findings suggest that EF skills may be improved even in long-term survivors by using a computerized, home-based intervention program. These improvements may potentially include subjective EF skills, which suggest a transfer of the training program to real-world behaviors.

Reduced hippocampal volume and verbal memory performance associated with interleukin-6 and tumor necrosis factor-alpha levels in chemotherapy-treated breast cancer survivors

Many survivors of breast cancer show significant cognitive impairments, including memory deficits. Inflammation induced by chemotherapy may contribute to hippocampal changes that underlie these deficits. In this cross-sectional study, we measured bilateral hippocampal volumes from high-resolution magnetic resonance images in 42 chemotherapy-treated breast cancer survivors and 35 healthy female controls. Patients with breast cancer were, on average, 4.8 ± 3.4 years off-therapy. In a subset of these participants (20 breast cancer, 23 controls), we quantified serum cytokine levels. Left hippocampal volumes and memory performance were significantly reduced and interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNFα) concentrations were significantly elevated in the breast cancer group compared to controls. In the breast cancer group, lower left hippocampal volume was associated with higher levels of TNFα and lower levels of IL-6 with a significant interaction between these two cytokines suggesting a potential modulatory effect of IL-6 on TNFα. Verbal memory performance was associated with cytokine levels and left hippocampal volume in both groups. These findings provide evidence of altered hippocampal volume and verbal memory difficulties following breast cancer chemotherapy that may be mediated by TNFα and IL-6.

Acknowledging the relevance of cognitive changes in cancer patients: perspectives of oncology practitioners in Asia

PURPOSE

Previous studies have suggested that cognitive impairment can affect cancer patients' health-related quality of life (HRQoL) and daily functioning. This study investigated oncology practitioners' perceptions of the relevance, effects, and causes of such cognitive changes in cancer patients, and their awareness of coping strategies.

METHODS

Oncology practitioners completed a self-administered cross-sectional survey. Practitioners were recruited from four major cancer centers in Singapore and Thailand, and through a regional cancer meeting that took place in Singapore in September 2011.

RESULTS

The sample (n = 193) consisted of nurses (51.3 %), oncologists (35.2 %), and pharmacists (13.5 %). Cognitive changes were frequently observed among cancer patients, particularly in the domains of memory (77.1 %) and concentration (74.6 %). The majority (86.5 %) of respondents agreed that cognitive changes adversely effected patients' HRQoL. The majority (65.3 %) of the respondents also recognized the need to implement routine neuropsychological assessments in clinical settings. The following factors were perceived as contributing to cognitive changes: aging (77.6 %), cancer-related fatigue (65.2 %), and anxiety (61.2 %). Compared with other healthcare professionals, oncologists were less likely to agree that chemotherapy was a major contributing factor to cognitive changes (25.0 % vs. 9.8 %, p = 0.038). Psychosocial support and the use of complementary alternative medicines (CAM) were identified as coping strategies for cognitive changes.

CONCLUSIONS

Healthcare professionals do not perceive a uniform set of contributing factors to cognitive impairment among cancer patients, although they all acknowledge that cancer patients' experience of cognitive impairment is a relevant issue.

IMPLICATIONS FOR CANCER SURVIVORS

It is important to equip clinicians with the knowledge necessary for monitoring and managing the cognitive disturbances and psychological distress experienced by at risk patients in a clinical setting.