Neurocognitive effects of chemotherapy and endocrine therapies in the treatment of breast cancer: recent perspectives

A Delphi technique toward the development of a cognitive intervention framework module for breast cancer survivors with cognitive impairment following chemotherapy

Objective

Chemotherapy-related cognitive impairment (CRCI) is a well-known phenomenon among breast cancer survivors. Cognitive impairment among breast cancer survivors can significantly affect their quality of life and ability to function independently. However, there is a lack of specific and focused cognitive intervention to improve their cognitive performances. This study aimed to develop a tailored cognitive intervention framework module by adapting the attention and memory interventions from the Cognitive Rehabilitation Manual of the Brain Injury Interdisciplinary Special Interest Group (BI-SIG) of the American Congress of Rehabilitation Medicine (ACRM) and incorporating them with the relevant exercises for cognitive rehabilitation for Malaysian breast cancer survivors with CRCI based on the consensus agreement of the expert panel.

Methods and analysis

The Delphi consensus technique was conducted online to review and evaluate the framework module. A panel of experts, including rehabilitation medicine physicians, occupational therapists, and clinical psychologists in Malaysia, was invited to participate in this study. For each round, the expert consensus was defined as more than 90% of the expert panel agreeing or strongly agreeing with the proposed items.

Results

A total of 33 practitioners completed the three Delphi rounds. 72.7% of the expert panel have been practising in their relevant clinical fields for more than six years (M = 10.67, SD = 5.68). In Round 1, 23% of the experts suggested that the framework module for attention training required further improvements, specifically in the language (M = 1.97, SD = 0.75) and instructions (M = 2.03, SD = 0.71) provided. In Round 2, 15% of the experts recommended additional changes in the instruction (M = 2.15, SD = 0.67) for attention training. Amendments made to the framework module in line with the recommendations provided by the experts resulted in a higher level of consensus, as 94% to 100% of the experts in Round 3 concluded the framework module was suitable and comprehensive for our breast cancer survivors. Following the key results, the objectives were practical, and the proposed approaches, strategies, and techniques for attention and memory training were feasible. The clarity of the instructions, procedures, verbatim transcripts, and timeframe further enhanced the efficacy and utility of the framework module.

Conclusions

This study found out that the cognitive intervention framework module for breast cancer survivors with cognitive impairment following chemotherapy can be successfully developed and feasible to be implemented using Delphi technique.

Predictors of health-related quality of life after completion of chemotherapy among Malaysian early-stage breast cancer survivors

PURPOSE

Health-related quality of life (QoL) is an important outcome measure in breast cancer management. Evidence of QoL of breast cancer patients in lower and middle-income countries remains scarce. We examined the level of QoL, cognitive impairment, psychological distresses, and the predictors of QoL among multiethnic Malaysian early-stage breast cancer survivors 1 to 3 years following chemotherapy.

METHODS

A total of 160 breast cancer survivors from the University of Malaya Medical Centre (UMMC) participated in this cross-sectional study. Their QoL was evaluated with the Malay version of the European Organization for Research and Treatment of Cancer (EORTC) Quality of Life Questionnaire Core 30 (QLQ-C30) version 3.0. Cognitive functioning and psychological distress were evaluated using the Malay version of the Montreal Cognitive Assessment (MoCA-BM) and Hospital Anxiety and Depression Scale (HADS), respectively. Data analysis was performed with Pearson's correlation and multiple regression analyses.

RESULTS

At 1- to 3-year post-chemotherapy, the mean EORTC QLQ-C30 global health status of the breast cancer survivors was relatively low (60.5 over 100, SD = 10.88). One-third (31.9%) of them demonstrated cognitive impairment, and another 3.2% showed moderate to severe anxiety levels. The significant predictors for global health status and functioning included age, psychological distresses, cognitive performance, fatigue, appetite loss, insomnia, pain, and constipation.

CONCLUSION

Our breast cancer survivors demonstrated poor global health status. Health care providers and policymakers must strive to provide holistic intervention strategies to improve the multiple dimensions of QoL and the cognitive and psychological functioning of this vulnerable population.

Stem cell therapies as a therapeutic option to counter chemo brain: a negative effect of cancer treatment

Chemo brain, a constellation of cognitive deficiencies followed by chemotherapy drugs, used to treat different types of cancers and adversely impacts the quality of life of a cancer survivor. The underlying mechanism of chemo brain remains vague, thus delaying the advancement of efficient treatments. Unfortunately, there is no US FDA approved medicine for chemo brain and often medicines considered for chemo brain are already the ones approved for other diseases. Nevertheless, researches exploring stem cell transplantation in different neurodegenerative diseases demonstrate that cellular transplantation could reverse chemotherapy-induced chemo brain. This review talks about the mechanism behind the cognitive impairments instigated by different chemotherapy drugs used in cancer treatment, and how stem cell therapy could be advantageous to overcome this disease.

The relationship between diet and cognitive function in adult cancer survivors: a systematic review

PURPOSE

To perform a systematic review identifying how dietary factors are related to cognitive function in cancer survivors who are not currently undergoing primary treatment.

METHODS

Using the PRISMA framework, a search was conducted for studies published before February 2019 across multiple databases, identifying 2304 unique articles. Twelve met final inclusion criteria and were evaluated through narrative synthesis. This review was registered with the International Prospective Register Of Systematic Reviews (CRD42018111941).

RESULTS

Included studies were heterogeneous in methodology and in dietary and cognitive variables investigated making direct comparisons difficult. Evidence of a relationship between diet and cognition was mixed; the most consistent evidence was identified in relation to a positive relationship between fruit and vegetable intake and cognitive function (both self-reported and objectively tested) in five out of six studies, but was not concordant across all studies.

CONCLUSION

Preliminary evidence exists that a greater fruit and vegetable intake is associated with better cognitive functioning in cancer survivors, as has been reported in healthy populations; however, these data are correlational and include relatively small samples. Most evidence related to breast cancer survivors, with individual studies extending to colorectal and stomach cancer survivors. Experimental trials are needed to identify causal attribution of dietary factors on cognitive function in cancer survivors.

IMPLICATIONS FOR CANCER SURVIVORS

At this time, there is not sufficient evidence to make dietary or nutritional recommendations specifically for improving cognitive function in cancer survivors. This should be considered in light of the general paucity of research on this subject, necessitating further investigations.

Cancer-related cognitive impairment and associated factors in a sample of older male oral-digestive cancer survivors

OBJECTIVE

This study examines the demographic and clinical variables associated with cancer-related cognitive impairment (CRCI) in a sample of older, male, oral-digestive cancer survivors at VA Medical Centers in Boston and Houston.

METHODS

A two-time point, longitudinal design was used, with cognitive assessment conducted at 6 and 18 months post-diagnosis. Using ANCOVA, the cognitive functioning of 88 older adults with head and neck, esophageal, gastric, or colorectal cancers was compared with that of 88 healthy controls. Paired t-tests examined cognitive change over time in the cancer group. Hierarchical linear regression examined variables potentially associated with cognitive impairment at 18 months.

RESULTS

Forty-eight percent of cancer patients exhibited cognitive impairment 6 months post-cancer diagnosis, and 40% at 18 months. Cancer survivors were impaired relative to controls on measures of sustained attention, memory, and verbal fluency at 18 months, controlling for age. Older age, low hemoglobin, and cancer-related PTSD were associated with worse cognition at 18 months.

CONCLUSIONS

CRCI is more frequent in older adults than reported in studies of younger adults and may be more frequent in men. Potential areas of intervention for CRCI include psychotherapy for cancer-related PTSD, treatment of anemia, and awareness of particularly vulnerable cognitive domains such as sustained attention, memory, and verbal fluency.

Neuropsychological profiles of breast cancer and brain tumor cohorts in Northeast Ontario, Canada

PURPOSE

As developments in cancer treatment have improved outcomes, research has increasingly focused on the role of cancer-related cognitive impairment (CRCI) in quality of life for cancer survivors. Impairment profiles have been heterogeneous across studies, necessitating the study of these effects across different cohorts. The purpose of this preliminary study is to compare the memory profiles of Northeast Ontario breast and CNS cancer patients, as there is no literature which exists for profiling CRCI within this largely rural region.

METHODS

Sixty-three outpatients with breast cancer (n = 32) or CNS tumors (n = 30) at the Northeast Cancer Centre in Sudbury, Canada, were administered a neuropsychological test battery as part of their clinical examination. Domains measured within this study included attention and concentration, processing speed, motor function, language skills, verbal and visual memory, and executive functioning.

RESULTS

Participants with brain tumors scored poorer on most neuropsychological measures than participants with breast cancer. Initial verbal memory for individuals with breast cancer was lower than delayed recall and recognition trials. Trial 1 performance for this group was also negatively correlated with self-reported anxiety scores.

CONCLUSIONS

Consistent with the literature, participants with breast cancer obtained higher scores on most test measures than participants with CNC tumors. Breast cancer participants had lower verbal memory scores on initial trials compared to delayed recall, potentially due to relationships with anxiety and attention. Further research into this cohort will strive to gain greater understanding of the patterns of deficits experienced and how these may inform individuals with cancer in other regions.

Putative mechanisms of cognitive decline with implications for clinical research and practice

Multiple intrinsic and extrinsic mechanisms contribute to vulnerability of cognitive decline and nurses play a significant role in assisting individuals and families to use strategies for healthy cognitive aging. The objective of this narrative review is to provide a synthesis of the intrinsic and extrinsic mechanisms of cognitive decline and conditions that are associated with cognitive decline. Well-established intrinsic mechanisms of cognitive decline include aging, apolipoprotein E (APOE) ε4 carrier status, SORL1 mutations, neuroinflammation, mitochondrial dysfunction, amyloid deposition, and demyelination. Extrinsic risk factors include obesity, diabetes, hypertension, elevated lipid panel, metabolic syndrome, depression, traumatic brain injury, substance use, heart failure, and stroke. The various definitions of cognitive decline as well as the intrinsic and extrinsic factors that impact cognition as humans age should be incorporated in future clinical research studies. Nurses may use this information to help patients make lifestyle choices regarding cognitive health.

Verbal fluency in breast cancer patients treated with chemotherapy

BACKGROUND

Cognitive decline caused by chemotherapy used in the treatment of malignant diseases was reported in several studies. ICCTF recommends the diagnosis of cognitive function in patient treated with chemotherapy. One of the suggested method is Verbal Fluency Test (VFT).

METHODS

Study was carried out on a group of 30 women with early breast cancer treated with adjuvant chemotherapy and 29 healthy controls. The patients underwent neuropsychological assessment using VFT at three time points: T1: before chemotherapy, T2: mid-chemotherapy and T3: post-chemotherapy. The examination in healthy controls was conducted at the same time intervals.

RESULTS

In phonetic fluency task patients produced more words at T2 compared to T1 (Z = 2.02; p < 0.05) and at T3 compared to T1, both patients (Z = 2.36; p < 0.05) and controls (Z = 2.57; p < 0.01). The patients scored lower than controls (Z = -2.04; p < 0.05) as well as on average cluster size in the same task (Z = -2.38; p < 0.05) at T3, while they scored higher on the number of phonetic switches at T2 compared to T1 (Z = 2.62; p < 0.01) and at T3 compared to T1 (Z = 2.50; p < 0.01). In semantic task controls produced more words at T3 than at T1 (Z = 2.62; p < 0.01) and at T3 compared to T2 (Z = 2.89; p < 0.01) and semantic clusters at T3 compared to T2 (Z = 2.43; p < 0.05). In patients, number of clusters was smaller at T3 compared to T2 (Z = -2.85; p < 0.05), while number of semantic switches was higher at T3 than at T2 (Z = 3.05; p < 0.01). Patients scored also lower than controls on number of semantic switches at T2 (Z = -2.05; p < 0.05).

CONCLUSIONS

Chemotherapy does not decrease verbal fluency, but it has a negative impact on semantic memory.

Cognitive impairment following hormone therapy: current opinion of research in breast and prostate cancer patients

PURPOSE OF REVIEW

Hormone therapy is a common cancer treatment that may be associated with numerous side and late effects, and in recent years, has been linked to changes in cognition. Here, we present the most important recent findings from empirical studies and reviews that have focused on the effects of hormone therapy on cognitive functioning in breast and prostate cancer populations, underline some general shortcomings, and propose directions for future research.

RECENT FINDINGS

Recent research indicates that cognitive impairment may occur in breast and prostate cancer patients following onset of hormone therapy. However, because of methodological shortcomings and heterogeneity of current research, conclusions regarding the effects of hormone therapy on cognitive functions remain tentative.

SUMMARY

The review highlights the general findings while also describing the many methodological shortcomings that need to be addressed in future research. It is clear that larger scale neuropsychological studies that also evaluate the impact of impairments on daily life functioning will improve our understanding of the effects of hormone therapy on cognition and inform the development of appropriate interventions.

Polymorphisms in DNA repair and oxidative stress genes associated with pre-treatment cognitive function in breast cancer survivors: an exploratory study

PURPOSE

The purpose of this exploratory candidate gene association study was to examine relationships between polymorphisms in oxidative stress and DNA repair genes and pre-adjuvant therapy cognitive function (CF) in postmenopausal women diagnosed with early stage-breast cancer.

METHODS

Using a neuropsychological test battery, CF was assessed in 138 women diagnosed with breast cancer prior to initiation of adjuvant therapy and 81 age- and education-matched controls and summarized across eight composites. Participants were genotyped for 39 functional or tagging single nucleotide polymorphisms (SNPs) of select oxidative stress (CAT, GPX1, SEPP1, SOD1, and SOD2) and DNA repair (ERCC2, ERCC3, ERCC5, and PARP1) genes. Multiple linear regression was used to determine if the presence or absence of one or more minor alleles account for variability in CF composite scores. Based on regression findings from the analysis of individual SNPs, weighted multi-gene, multi-polymorphism genetic risk scores (GRSs) were calculated to evaluate the collective effect of possession of multiple protective and/or risk alleles.

RESULTS

Each CF composite was significantly (p < 0.05) associated with one or more oxidative stress and DNA repair gene polymorphisms evaluated either by SNP main effects and/or SNP-by-prescribed breast cancer treatment group interactions. Each computed GRS was found to be significantly (p < 0.001) related to its corresponding CF composite. All associations were positive suggesting that as overall genetic protection increases, CF composite score increases (indicating better performance).

CONCLUSIONS

These findings suggest that genetic variation in the oxidative stress and DNA repair pathways may play an important role in pre-adjuvant therapy CF in breast cancer survivors.

A feasibility study exploring the role of pre-operative assessment when examining the mechanism of 'chemo-brain' in breast cancer patients

Background

Women receiving chemotherapy treatment for breast cancer may experience problems with their memory and attention (cognition), which is distressing and interferes with quality of life. It is unclear what causes or contributes to the problems they report: psychological distress, fatigue, coping style, or specific biological changes for example to pro inflammatory cytokines. Research shows however, that approximately a third of women with breast cancer perform poorly on tests of cognition before commencing chemotherapy. We aimed to examine the acceptability and relevance of pre-surgical assessments (bloods, brain imaging, cognitive tests and self-report questionnaires) when investigating the phenomenon of ‘chemo-brain’ and investigate whether inflammatory markers mediate chemotherapy-induced neuropsychological impairments in women treated for breast cancer.

Methods

Women with early stage breast cancer completed neuropsychological and quality of life assessments at T1 (pre-surgery), T2 (post-surgery before chemotherapy) and T3 (6 months later). Blood cytokine levels were measured at the same time points and brain imaging was performed at T1 and T3.

Results

In total, 14/58 women participated (8 chemotherapy, 6 non-chemotherapy). Prior to the start of chemotherapy a decline in cognitive performance compared to baseline was observed in one participant. At T3 women who received chemotherapy reported poorer quality of life and greater fatigue. Increases in soluble tumour necrosis factor receptor II (sTNFRII), interleukin-6, interleukin-10 and vascular endothelial growth factor occurred post chemotherapy only. Levels of sTNFRII were inversely correlated with grey matter volume (GMV) of the right posterior insula in both groups. At T3, the chemotherapy group displayed a greater reduction in GMV in the subgenual and dorsal anterior cingulate, and the inferior temporal gyrus.

Conclusions

Pre-operative recruitment to the study was challenging; however, the lack of significant changes in blood cytokine levels and neuropsychological tests at T2 implies that post surgery may be a valid baseline assessment, but this needs further investigation in a larger study. The preliminary results support the hypothesis that chemotherapy induced fatigue is mediated by a change in peripheral cytokine levels which could explain some symptoms of ‘chemo brain’ experienced by patients.

Associations Between Physical Fitness Indices and Working Memory in Breast Cancer Survivors and Age-Matched Controls

BACKGROUND

This study examined the effects of cardiorespiratory fitness, heart rate recovery, and physical activity on working memory in breast cancer survivors and age-matched controls.

METHOD

Using a case-control design, 32 women who had received a breast cancer diagnosis and completed primary treatment within the past 36-months (11 radiation only; 21 chemotherapy) and 30 age-matched women with no previous cancer diagnosis completed a n-back continuous performance task commonly used as an assessment of working memory. In addition, cardiorespiratory fitness and heart rate recovery were measured during a submaximal graded exercise test and physical activity was measured using 7-days of accelerometer monitoring.

RESULTS

Breast cancer survivors who had received chemotherapy had poorer heart rate recovery (p = .010) and engaged in less physical activity than women who had received radiation only (p = .004) or non-cancer controls (p = .029). Cancer treatment (radiation; chemotherapy) predicted differences in reaction times on the 1-back working memory task (p = .029). However, more rapid heart rate recovery predicted shorter reaction times on the 1-back task in the age-matched control group (p = .002). All participants with greater cardiorespiratory fitness displayed greater accuracy independent of disease status on the 1-back task (p = .017). No significant group differences in reaction times were observed for 2-back target trials between breast cancer survivors and controls. However, greater total physical activity predicted shorter reaction times in breast cancer survivors (radiation, chemotherapy) on the 2-back task (p = .014). In addition, all participants who exhibited more rapid heart rate recovery demonstrated better greater accuracy regardless of disease status (p = .013).

CONCLUSION

These findings support differences in physical activty participation, heart rate recovery, and 1- and 2-back working memory reaction times between breast cancer survivors and age-matched controls. Greater cardiorespiratory fitness, heart rate recovery, and physical activity were positively associated with better working memory performance across conditions.

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.

Apolipoprotein E genotype and cognitive function in postmenopausal women with early-stage breast cancer

PURPOSE/OBJECTIVES

To examine the role of apolipoprotein E (APOE) genotype in the cognitive function of postmenopausal women with early-stage breast cancer prior to initiation of adjuvant therapy and over time with treatment.

DESIGN

Longitudinal, genetic association study.

SETTING

Urban university cancer center.

SAMPLE

Three cohorts of postmenopausal women: 37 women with breast cancer receiving chemotherapy and anastrozole, 41 women with breast cancer receiving anastrozole alone, and 50 healthy women.

METHODS

Cognitive function was evaluated three times during a 12-month period using a comprehensive neuropsychological test battery. Participants were genotyped and classified based on the presence or absence of at least one APOE e4 allele. Multiple linear regression was used to determine if APOE genotype accounted for observed variability in cognitive function data.

MAIN RESEARCH VARIABLES

APOE genotype, breast cancer treatment, and cognitive function.

FINDINGS

Performance or changes in performance on tasks of executive function, attention, verbal learning and memory, and visual learning and memory were found to be influenced by APOE genotype and/or interactions between APOE genotype and study cohort.

CONCLUSIONS

The results indicate that cognitive function in postmenopausal women with breast cancer is modified by APOE genotype and the combination of APOE genotype and treatment.

IMPLICATIONS FOR NURSING

APOE genotype, along with other biomarkers, may be used in the future to assist nurses in identifying women with breast cancer most at risk for cognitive decline.

Recovery correction technique for NMR spectroscopy of perchloric acid extracts using DL-valine-2,3-d2: validation and application to 5-fluorouracil-induced brain damage

PURPOSE

We explored a recovery correction technique that can correct metabolite loss during perchloric acid (PCA) extraction and minimize inter-assay variance in quantitative (1)H nuclear magnetic resonance (NMR) spectroscopy of the brain and evaluated its efficacy in 5-fluorouracil (5-FU)- and saline-administered rats.

METHODS

We measured the recovery of creatine and dl-valine-2,3-d2 from PCA extract containing both compounds (0.5 to 8 mM). We intravenously administered either 5-FU for 4 days (total, 100 mg/kg body weight) or saline into 2 groups of 11 rats each. We subsequently performed PCA extraction of the whole brain on Day 9, externally adding 7 µmol of dl-valine-2,3-d2. We estimated metabolite concentrations using an NMR spectrometer with recovery correction, correcting metabolite concentrations based on the recovery factor of dl-valine-2,3-d2. For each metabolite concentration, we calculated the coefficient of variation (CEV) and compared differences between the 2 groups using unpaired t-test.

RESULTS

Equivalent recoveries of dl-valine-2,3-d2 (89.4 ± 3.9%) and creatine (89.7 ± 3.9%) in the PCA extract of the mixed solution indicated the suitability of dl-valine-2,3-d2 as an internal reference. In the rat study, recovery of dl-valine-2,3-d2 was 90.6 ± 9.2%. Nine major metabolite concentrations adjusted by recovery of dl-valine-2,3-d2 in saline-administered rats were comparable to data in the literature. CEVs of these metabolites were reduced from 10 to 17% before to 7 to 16% after correction. The significance of differences in alanine and taurine between the 5-FU- and saline-administered groups was determined only after recovery correction (0.75 ± 0.12 versus 0.86 ± 0.07 for alanine; 5.17 ± 0.59 versus 5.66 ± 0.42 for taurine [µmol/g brain tissue]; P < 0.05).

CONCLUSION

A new recovery correction technique corrected metabolite loss during PCA extraction, minimized inter-assay variance in quantitative (1)H NMR spectroscopy of brain tissue, and effectively detected inter-group differences in concentrations of brain metabolites between 5-FU- and saline-administered rats.

Altered cerebral blood flow one month after systemic chemotherapy for breast cancer: a prospective study using pulsed arterial spin labeling MRI perfusion

Cerebral structural and functional alterations have been reported after chemotherapy for non-CNS cancers, yet the causative mechanism behind these changes remains unclear. This study employed a novel, non-invasive, MRI-based neuroimaging measure to provide the first direct longitudinal measurement of resting cerebral perfusion in breast cancer patients, which was tested for association with changes in cognitive function and gray matter density. Perfusion was measured using pulsed arterial spin labeling MRI in women with breast cancer treated with (N = 27) or without (N = 26) chemotherapy and matched healthy controls (N = 26) after surgery before other treatments (baseline), and one month after chemotherapy completion or yoked intervals. Voxel-based analysis was employed to assess perfusion in gray matter; changes were examined in relation to overall neuropsychological test performance and frontal gray matter density changes measured by structural MRI. Baseline perfusion was not significantly different across groups. Unlike control groups, chemotherapy-treated patients demonstrated significantly increased perfusion post-treatment relative to baseline, which was statistically significant relative to controls in the right precentral gyrus. This perfusion increase was negatively correlated with baseline overall neuropsychological performance, but was not associated with frontal gray matter density reduction. However, decreased frontal gray matter density was associated with decreased perfusion in bilateral frontal and parietal lobes in the chemotherapy-treated group. These findings indicate that chemotherapy is associated with alterations in cerebral perfusion which are both related to and independent of gray matter changes. This pattern of results suggests the involvement of multiple mechanisms of chemotherapy-induced cognitive dysfunction. Additionally, lower baseline cognitive function may be a risk factor for treatment-associated perfusion dysregulation. Future research is needed to clarify these mechanisms, identify individual differences in susceptibility to treatment-associated changes, and further examine perfusion change over time in survivors.

Persistent cognitive changes in breast cancer patients 1 year following completion of chemotherapy

Numerous studies have shown that there are acute cognitive side-effects of chemotherapy for breast cancer. Presumably, patients are more concerned about chronic treatment effects. This report from a prospective longitudinal study compares cognitive functioning in 56 breast cancer patients 1 year after chemotherapy to that of 56 healthy individuals. Neuropsychological test scores were combined into verbal memory, visual memory, working memory, and processing speed scores, as well as an overall summary score, and analyzed using multi-level growth modeling. Frequency of cognitive decline was assessed using regression-based change scores. There was significant rebound in the overall summary score from end of treatment to 1-year follow-up as well as a substantial reduction in the frequency of cognitive decline. However, more than one-third of the breast cancer patients who showed cognitive decline immediately following completion of chemotherapy showed persistent cognitive decline 1 year later. Furthermore, recovery was not seen in all cognitive domains. In fact, the rebound was significant only for working memory. Longer multi-site studies are recommended to explore the risk factors for and the permanence of these longer-term cognitive effects.

Neural correlates of chemotherapy-related cognitive impairment

Cancer survivors frequently experience cognitive deficits following chemotherapy. The most commonly affected functions include memory, attention and executive control. The present paper reviews animal research and clinical studies including event-related potential (ERP) and neuroimaging investigations of chemotherapy-related changes of brain structure and function. In rodents, chemotherapeutic substances have been shown to damage neural precursor cells and white matter tracts and are associated with impairments of learning and memory. Structural and functional changes associated with chemotherapy have also been observed in humans. Structural imaging has revealed gray and white matter volume reductions and altered white matter microstructure. Functional studies using either ERPs or hemodynamic imaging have shown that chemotherapy alters the activation patterns of cortical networks involved in higher cognitive functions. Collectively, these findings support the existence of the "chemobrain" phenomenon beyond the patients' subjective reports. However, the rather small number of studies and methodological limitations of some of the pioneering investigations call for further research of high methodological quality, including larger numbers of subjects with appropriate controls to delineate the temporal and spatial pattern of chemotherapy-associated central nervous system (CNS) toxicity. Brain activation studies in humans might systematically vary task difficulty levels to distinguish between compensatory hyper-activations on the one hand and deficient recruitment of resources on the other hand. Integrative functions could be tested by connectivity analyses using both electrophysiological and hemodynamic measures. The ultimate goal should be the development of cognitive-behavioral and pharmacological interventions to reduce the cognitive side effects of the medically indispensable but neurotoxic chemotherapeutic treatments.

Neuroimaging biomarkers and cognitive function in non-CNS cancer and its treatment: current status and recommendations for future research

Cognitive changes in patients undergoing treatment for non-central nervous system (CNS) cancers have been recognized for several decades, yet the underlying mechanisms are not well understood. Structural, functional and molecular neuroimaging has the potential to help clarify the neural bases of these cognitive abnormalities. Structural magnetic resonance imaging (MRI), functional MRI (fMRI), diffusion tensor imaging (DTI), MR spectroscopy (MRS), and positron emission tomography (PET) have all been employed in the study of cognitive effects of cancer treatment, with most studies focusing on breast cancer and changes thought to be induced by chemotherapy. Articles in this special issue of Brain Imaging and Behavior are devoted to neuroimaging studies of cognitive changes in patients with non-CNS cancer and include comprehensive critical reviews and novel research findings. The broad conclusions that can be drawn from past studies and the present body of new research is that there are structural and functional changes associated with cancer and various treatments, particularly systemic cytotoxic chemotherapy, although some cognitive and fMRI studies have identified changes at pre-treatment baseline. Recommendations to accelerate progress include well-powered multicenter neuroimaging studies, a better standardized definition of the cognitive phenotype and extension to other cancers. A systems biology framework incorporating multimodality neuroimaging, genetics and other biomarkers will be highly informative regarding individual differences in risk and protective factors and disease- and treatment-related mechanisms. Studies of interventions targeting cognitive changes are also needed. These next steps are expected to identify novel protective strategies and facilitate a more personalized medicine for cancer patients.

Cognitive impairment in gynecologic cancers: a systematic review of current approaches to diagnosis and treatment

PURPOSE

To review the etiology and assessment of chemotherapy-related cognitive impairment (CRCI). To explore current treatment and prevention strategies for CRCI and propose future research goals in the field of gynecologic oncology.

METHODS

Computerized searches in PubMed of cognitive impairment in cancer between 2000 and 2012 were conducted. The inclusion criteria were randomized control trials evaluating treatment of CRCI and search terms 'cognitive function, cognitive impairment, cognitive decline, chemobrain, chemofog, and cancer'.

RESULTS

To date, numerous modalities have been utilized for assessing CRCI in patients undergoing therapy. It has been proposed to move towards web-based assessment modalities as a possible standard. Few studies have aimed to elucidate possible treatment and prevention options for CRCI; even less in the field of gynecologic oncology. Only seven of these studies were subjected to randomized control trials. Only one of these studies looked at treatment in patients with gynecologic cancers.

CONCLUSIONS

The etiology of CRCI is multi-factorial. Following from this, there is no consensus on the best way to assess CRCI although objective measures are more reliable. One must extrapolate data from the non-gynecologic cancer literature, even venturing to non-cancer literature, to explore the treatment and prevention of CRCI. The methods found in these areas of research have not yet been applied to CRCI in gynecologic oncology.

A pilot study of prospective memory functioning in early breast cancer survivors

AIMS

To evaluate prospective memory (PM) functioning in early breast cancer (BC) survivors and its association with fatigue and depression.

METHODS

The Memory for Intention Screening Test, the Center for Epidemiologic Studies Depression Scale and the Functional Assessment of Cancer Therapy-Fatigue subscale were administered to 80 patients and 80 aged-matched healthy controls.

RESULTS

Patients performed more poorly than controls on the memory test (p < 0.001) and had a higher rate of impairment (odds ratio = 5.5, p < 0.01). Fatigue mediated the relationship between Group membership and PM performance.

CONCLUSIONS

BC survivors exhibited a clear pattern of PM deficit and fatigue was a major contributor to this deficit. This suggests that a common mechanism may be involved in fatigue symptoms and memory disturbances experienced by patients. Further research is needed to evaluate the role of adjuvant therapy in PM deficits and to explore whether interventions targeted at improving fatigue may also improve memory functioning in BC survivors.

Opening up the window into "chemobrain": a neuroimaging review

As more chemotherapy-treated cancer patients are reaching survivorship, side-effects such as cognitive impairment warrant research attention. The advent of neuroimaging has helped uncover a neural basis for these deficits. This paper offers a review of neuroimaging investigations in chemotherapy-treated adult cancer patients, discussing the benefits and limitations of each technique and study design. Additionally, despite the assumption given by the chemobrain label that chemotherapy is the only causative agent of these deficits, other factors will be considered. Suggestions are made on how to more comprehensively study these cognitive changes using imaging techniques, thereby promoting generalizability of the results to clinical applications. Continued investigations may yield better long-term quality of life outcomes by supporting patients' self-reports, and revealing brain regions being affected by chemotherapy.

Inhibition of p38 mitogen-activated protein kinase alters microRNA expression and reverses epithelial-to-mesenchymal transition

Acquired chemoresistance and epithelial-to-mesenchymal transition (EMT) are hallmarks of cancer progression and of increasing clinical relevance. We investigated the role of miRNA and p38 mitogen-activated protein kinase (MAPK) signaling in the progression of breast cancer to a drug-resistant and mesenchymal phenotype. We demonstrate that acquired death receptor resistance results in increased hormone-independent tumorigenesis compared to hormone-sensitive parental cells. Utilizing global miRNA gene expression profiling, we identified miRNA alterations associated with the development of death receptor resistance and EMT progression. We further investigated the role of p38 MAPK in this process, showing dose-dependent inactivation of p38 by its inhibitor RWJ67657 and decreased downstream ATF and NF-κB signaling. Pharmacological inhibition of p38 also decreased chemoresistant cancer tumor growth in xenograft animal models. Interestingly, inhibition of p38 partially reversed the EMT changes found in this cell system, as illustrated by decreased gene expression of the EMT markers Twist, Snail, Slug and ZEB and protein and mRNA levels of Twist, a known EMT promoter, concomitant with decreased N-cadherin protein. RWJ67657 treatment also altered the expression of several miRNAs known to promote therapeutic resistance, including miR-200, miR-303, miR-302, miR-199 and miR-328. Taken together, our results demonstrate the roles of multiple microRNAs and p38 signaling in the progression of cancer and demonstrate the therapeutic potential of targeting the p38 MAPK pathway for reversing EMT in an advanced tumor phenotype.

Lack of a chemobrain effect for adjuvant FOLFOX chemotherapy in colon cancer patients. A pilot study

PURPOSE

Chemotherapy improves the survival rate of stage III colon cancer patients. The combination of oxaliplatin, 5-fluorouracil, and leucovorin (the FOLFOX4 regimen) has emerged as the standard of care. This prospective study evaluates potential alterations in cognitive function in FOLFOX4-treated patients.

METHODS

We evaluated 57 consecutive colorectal cancer patients who received adjuvant chemotherapy with FOLFOX4. Patients underwent a complete battery of neuropsychological tests at three different times: before (T0), at the end (T1), and 6 months after treatment (T2).

RESULTS

We have analyzed cognitive impairment (Mini Mental State Examination, MMSE), visuo-spatial memory (Clock Drawing Test, CDT, Rey Complex Figure, copy and recall), information processing speed (Trial Making Test-A, TMT-A, and Trial Making Test-B, TMT-B), verbal memory (Rey Auditory Verbal Learning Test, call and recall), emotional distress (Psychological Distress Inventory, PDI), anxiety (State and Trait Anxiety Inventory, STAI-Y1 and Y2), and depression (Beck Depression Inventory, BDI). Then we have calculated, for each test and for each interval of time, mean ± standard deviation for the mean. In a subsequent phase, we tested the significance of different results through the ANOVA analysis for repeated measures. In this case, we could not find any statistically significant modification in cognitive function, but we could notice an improvement in emotional performance, anxiety and depression a short time after chemotherapy administration.

CONCLUSIONS

We found no effect on cognitive function related to chemotherapy, the only little modification is about some emotional performance during chemotherapy. These findings may be explained by the central role of the psychological adaptation process, which occurs during the period from diagnosis to completion of treatment and is characterized by anxiety and adjustment depression. Our results seem to rule out any significant cognitive impairment due to adjuvant FOLFOX4 chemotherapy in colon cancer patients.