Subtle hippocampal deformities in breast cancer survivors with reduced episodic memory and self-reported cognitive concerns

You can't spell distress without stress: Expanding our perspective of the intersection between mental and physical health in cancer survivors

Although many breast cancer survivors adjust to cancer treatment and survivorship, a sizable subgroup of women do not do so, resulting in psychological distress. Over time, this psychological distress can contribute to immune dysfunction and accompanying worsened physical symptoms as women navigate survivorship. Dr. Kiecolt-Glaser's work and mentorship has been integral to our understanding of breast cancer survivors' immune risks, and how behavioral factors may enhance these risks. As a postdoctoral fellow in the Stress and Health Lab, under Dr. Kiecolt-Glaser's mentorship, my research focused on understanding how distress is associated with immune functioning and physical health in breast cancer survivors. In this paper, we highlight Dr. Kiecolt-Glaser's influence on our careers as a strong female research and mentor, the work completed under her mentorship, and how the field of psychoneuroimmunology can continue to expand her research to better understand how distress in the cancer context confers long-term health risks.

Effect of chemotherapy on hippocampal volume and shape in older long-term breast cancer survivors

Purpose

The objective of this study was to assess changes in hippocampal volume and shape in older long-term breast cancer survivors who were exposed to chemotherapy 5-15 years prior.

Methods

This study recruited female long-term breast cancer survivors aged 65 years or older with a history of chemotherapy (C+), age-matched breast cancer survivors who did not receive chemotherapy (C-), and healthy controls (HC). The participants were recruited 5-15 years after chemotherapy at time point 1 (TP1) and were followed up for 2 years at time point 2 (TP2). Assessments included hippocampal volume and shape from brain MRI scans and neuropsychological (NP) tests.

Results

At TP1, each of the three groups was comprised of 20 participants. The C+ group exhibited a hippocampal volume loss estimated in proportion with total intracranial volume (ICV) in both the left and right hemispheres from TP1 to TP2. Regarding the hippocampal shape at TP1, the C+ group displayed inward changes compared to the control groups. Within the C+ group, changes in right hippocampal volume adjusted with ICV were positively correlated with crystalized composite scores (R = 0.450, p = 0.044). Additionally, in C+ groups, chronological age was negatively correlated with right hippocampal volume adjusted with ICV (R = -0.585, p = 0.007).

Conclusion

The observed hippocampal volume reduction and inward shape deformation within the C+ group may serve as neural basis for cognitive changes in older long-term breast cancer survivors with history of chemotherapy treatment.

Fibre-rich diet attenuates chemotherapy-related neuroinflammation in mice

The gastrointestinal microbiota has received increasing recognition as a key mediator of neurological conditions with neuroinflammatory features, through its production of the bioactive metabolites, short-chain fatty acids (SCFAs). Although neuroinflammation is a hallmark shared by the neuropsychological complications of chemotherapy (including cognitive impairment, fatigue and depression), the use of microbial-based therapeutics has not previously been studied in this setting. Therefore, we aimed to investigate the effect of a high fibre diet known to modulate the microbiota, and its associated metabolome, on neuroinflammation caused by the common chemotherapeutic agent 5-fluorouracil (5-FU). Twenty-four female C57Bl/6 mice were treated with 5-FU (400 mg/kg, intraperitoneal, i.p.) or vehicle control, with or without a high fibre diet (constituting amylose starch; 4.7 % crude fibre content), given one week prior to 5-FU and until study completion (16 days after 5-FU). Faecal pellets were collected longitudinally for 16S rRNA gene sequencing and terminal SCFA concentrations of the caecal contents were quantified using gas chromatography-mass spectrometry (GC-MS). Neuroinflammation was determined by immunofluorescent analysis of astrocyte density (GFAP). The high fibre diet significantly altered gut microbiota composition, increasing the abundance of Bacteroidaceae and Akkermansiaceae (p < 0.0001 and p = 0.0179) whilst increasing the production of propionate (p = 0.0097). In the context of 5-FU, the diet reduced GFAP expression in the CA1 region of the hippocampus (p < 0.0001) as well as the midbrain (p = 0.0216). Astrocyte density negatively correlated with propionate concentrations and the abundance of Bacteroidaceae and Akkermansiaceae, suggesting a relationship between neuroinflammatory and gastrointestinal markers in this model. This study provides the first evidence of the neuroprotective effects of fibre via dietary intake in alleviating the neuroimmune changes seen in response to systemically administered 5-FU, indicating that the microbiota-gut-brain axis is a targetable mediator to reduce the neurotoxic effects of chemotherapy treatment.

Brain gray matter reduction and premature brain aging after breast cancer chemotherapy: a longitudinal multicenter data pooling analysis

Brain gray matter (GM) reductions have been reported after breast cancer chemotherapy, typically in small and/or cross-sectional cohorts, most commonly using voxel-based morphometry (VBM). There has been little examination of approaches such as deformation-based morphometry (DBM), machine-learning-based brain aging metrics, or the relationship of clinical and demographic risk factors to GM reduction. This international data pooling study begins to address these questions. Participants included breast cancer patients treated with (CT+, n = 183) and without (CT-, n = 155) chemotherapy and noncancer controls (NC, n = 145), scanned pre- and post-chemotherapy or comparable intervals. VBM and DBM examined GM volume. Estimated brain aging was compared to chronological aging. Correlation analyses examined associations between VBM, DBM, and brain age, and between neuroimaging outcomes, baseline age, and time since chemotherapy completion. CT+ showed longitudinal GM volume reductions, primarily in frontal regions, with a broader spatial extent on DBM than VBM. CT- showed smaller clusters of GM reduction using both methods. Predicted brain aging was significantly greater in CT+ than NC, and older baseline age correlated with greater brain aging. Time since chemotherapy negatively correlated with brain aging and annual GM loss. This large-scale data pooling analysis confirmed findings of frontal lobe GM reduction after breast cancer chemotherapy. Milder changes were evident in patients not receiving chemotherapy. CT+ also demonstrated premature brain aging relative to NC, particularly at older age, but showed evidence for at least partial GM recovery over time. When validated in future studies, such knowledge could assist in weighing the risks and benefits of treatment strategies.

Cancer-related cognitive impairment in racial and ethnic minority groups: a scoping review

PURPOSE

Disparities in cognitive function among racial and ethnic groups have been reported in non-cancer conditions, but cancer-related cognitive impairment (CRCI) in racial and ethnic minority groups is poorly understood. We aimed to synthesize and characterize the available literature about CRCI in racial and ethnic minority populations.

METHODS

We conducted a scoping review in the PubMed, PsycInfo, and Cumulative Index to Nursing and Allied Health Literature databases. Articles were included if they were published in English or Spanish, reported cognitive functioning in adults diagnosed with cancer, and characterized the race or ethnicity of the participants. Literature reviews, commentaries, letters to the editor, and gray literature were excluded.

RESULTS

Seventy-four articles met the inclusion criteria, but only 33.8% differentiated the CRCI findings by racial or ethnic subgroups. There were associations between cognitive outcomes and the participants' race or ethnicity. Additionally, some studies found that Black and non-white individuals with cancer were more likely to experience CRCI than their white counterparts. Biological, sociocultural, and instrumentation factors were associated with CRCI differences between racial and ethnic groups.

CONCLUSIONS

Our findings indicate that racial and ethnic minoritized individuals  may be disparately affected by CRCI. Future research should use standardized guidelines for measuring and reporting the self-identified racial and ethnic composition of the sample; differentiate CRCI findings by racial and ethnic subgroups; consider the influence of structural racism in health outcomes; and develop strategies to promote the participation of members of racial and ethnic minority groups.

Worry and Mindfulness Differentially Impact Symptom Burden Following Treatment Among Breast Cancer Survivors: Findings From a Randomized Crossover Trial

BACKGROUND

Breast cancer survivors often experience many somatic and cognitive side effects resulting from their cancer diagnosis and treatment, including higher rates of pain, fatigue, and memory/concentration problems. Emotion regulation offers opportunities to either enhance or dampen physical health.

PURPOSE

In a secondary analysis of a double-blind randomized controlled trial (RCT) using a typhoid vaccine to assess factors associated with breast cancer survivors' inflammatory responses, we assessed how two specific aspects of emotion regulation, mindfulness, and worry, corresponded to acute changes in focus problems, memory problems, and fatigue along with performance on pain sensitivity and cognitive tasks across two visits among breast cancer survivors.

METHODS

Breast cancer survivors (N = 149) completed two 8.5-hr visits at a clinical research center. Survivors were randomized to either the vaccine/saline placebo or a placebo/vaccine sequence. Worry and mindfulness questionnaires provided data on trait-level emotion regulation abilities. Fatigue, memory problems, and focus difficulties were assessed via Likert scales six times-once before the injections and then every 90 min for 7.5 hr thereafter. Women also completed a pain sensitivity task and several cognitive tasks at each visit.

RESULTS

Findings from this study showed that breast cancer survivors who worried more and were less mindful experienced subjective memory problems, focus problems, and cold pain sensitivity across two visits and irrespective of injection type. Lower mindfulness also corresponded to higher subjective fatigue and hot pain sensitivity and objective ratings. Emotion regulation skills did not predict objective pain sensitivity or cognitive problems.

CONCLUSION

Results from this study highlight the benefits of adaptive emotion regulation in helping mitigate symptoms associated with breast cancer survivorship.

[Cognitive deficits with chemotherapy in women with breast cancer: a bibliographic revisión]

Background

Patients with breast cancer may experience cognitive difficulties from  chemotherapy. This alteration is called Chemoinduced Cognitive Impairment, also known as Chemobrain or Chemofog.

Objective

To identify the cognitive profile and the characteristics of the neuropsychological assessment in this population. Method: PubMed, SpringerLink and SciELO databases were revised. Articles from 1994 to September 2021 were selected. Keywords related to the study topic were used.

Results

Chemotherapy can cause cognitive impairment between 15 and 50% of women. This disturbance may be from multiple aetiologies and can be associated with biological factors and functional and/or structural changes of the CNS. Sociodemographic, clinical and psychological factors should be considered as modulating variables. It manifests mainly with memory problems, executive function, attention and processing speed impairment. It can be measured through neuropsychological evaluation instruments.

Discussion and conclusion

We suggest that chemo-induced cognitive impairment should be included to the informed consent. Further development of longitudinal studies complemented with neuroimages that allow us to advance in the knowledge of this problem is recommended. A neuropsychological protocol is proposed, which includes screening tests, clinical scales, specific cognitive tests and quality of life questionnaires, within the recommendations of the International Cognition and Cancer Task Force.

Altered resting-state hippocampal functional connectivity in breast cancer survivors with chemotherapy-induced amenorrhea

INTRODUCTION

Amenorrhea induced decrease of hormones is associated with cognitive impairment. This study aimed to evaluate hippocampal functional connectivity patterns in chemotherapy-induced amenorrhea (CIA) breast cancer (BC) patients, to evaluate the relationship between the functional connectivity features and hormone levels.

METHOD

Neuropsychological test, functional magnetic resonance imaging, and assessment of hormone levels were conducted in 21 premenopausal BC patients before chemotherapy (t0 ) and 1 week after completing chemotherapy (t1 ). Twenty matched healthy controls (HC) were also included and underwent the same assessments at similar time intervals. Mixed effect analysis and paired t-test were used to compare differences in brain functional connectivity.

RESULTS

Voxel-based paired t-tests revealed increased functional connectivity of the right and left hippocampus with the left fusiform gyrus, inferior and middle temporal gyrus, inferior occipital gyrus, left lingual gyrus, and parahippocampal gyrus after chemotherapy (p < .001) in CIA patients. Repeated measures analysis revealed significant group-by-time interactions in the left hippocampus with the bilateral fusiform gyrus, right parahippocampal gyrus, left inferior temporal gyrus, and left inferior occipital gyrus (p < .001). Premenopausal BC patients had no significant differences in cognitive function compared with HC at baseline. However, the CIA patients had high levels of self-rating depression scale, self-rating anxiety scale, total cholesterol, and triglycerides. Further, the CIA patients showed significant differences in hormone and fasting plasma glucose levels and cognitive performances between t0 and t1 (p < .05). Functional connectivity changes between the left hippocampus and the left inferior occipital gyrus was negatively correlated with E2 and luteinizing hormone changes (p < .05).

CONCLUSION

The CIA patients had cognitive dysfunction mainly in memory and visual mobility. Chemotherapy may affect hippocampal-posterior cortical circuit which mediates visual processing in CIA patients. Moreover, E2 may be involved in this process.

5-Fluorouracil Induces an Acute Reduction in Neurogenesis and Persistent Neuroinflammation in a Mouse Model of the Neuropsychological Complications of Chemotherapy

The neuropsychological symptoms associated with chemotherapy treatment remain a major challenge with their prevention hampered by insufficient understanding of pathophysiology. While long-term neuroimmune changes have been identified as a hallmark feature shared by neurological symptoms, the exact timeline of mechanistic events preceding neuroinflammation, and the relationship between the glial cells driving this neuroinflammatory response, remain unclear. We therefore aimed to longitudinally characterize the neuroimmunological changes following systemic 5-fluorouracil (5-FU) treatment to gain insight into the timeline of events preceding the well-documented chronic neuroinflammation seen following chemotherapy. Eighteen female C57Bl/6 mice received a single intraperitoneal dose of 5-FU and groups were killed at days 1 and 2 (acute timepoint), days 4 and 8 (subacute timepoint), and days 16 and 32 (chronic timepoint). A further six mice were administered with vehicle control with tissues collected from three mice on day 1 and day 32 of the study. The expression of key genes of interest, BCL2, BDNF, TIMP1, MMP-9, MMP-2, TNFα, IL-1β, and IL-6R were assessed using real time polymerase chain reaction. Levels of neurogenesis were determined through immunofluorescent staining of doublecortin (DCX). The density of microglia and astrocytes were assessed using immunofluorescence staining of Iba1 and GFAP respectively. 5-FU treatment caused significant decreases to DCX staining at acute timepoints (p = 0.0030) which was positively correlated with BCL2 expression levels. An increase to microglial density was observed in the prefrontal cortex (p = 0.0256), CA3 region (p = 0.0283), and dentate gyrus (p = 0.0052) of the hippocampus at acute timepoints. 5-FU caused increases to astrocyte density, across multiple brains regions, at subacute and chronic timepoints which were positively correlated with TNFα, TIMP-1, MMP-2, and IL-6R expression. This study has identified acute objective neuroinflammatory changes suggesting that the role of early intervention should be explored to prevent the development of neuropsychological deficits in the longer-term following chemotherapy.

Episodic Memory and Recollection Network Disruptions Following Chemotherapy Treatment in Breast Cancer Survivors: A Review of Neuroimaging Findings

Simple Summary

Memory disturbances are amongst the most common and disruptive symptoms of chemotherapy-related cognitive impairment. Chemotherapy treatments commonly cause neurotoxicity within the hippocampus, creating a vulnerability to memory impairment. Most clinical assessments of long-term memory in breast cancer survivors assess basic verbal and visual memory processing, and do not capture the complexities of everyday event memories, including episodic and autobiographical memory. This review focuses on structural and functional neuroimaging studies identifying disruptions in the hippocampus and recollection network, and related episodic memory impairments in chemotherapy-treated breast cancer survivors. We argue for the need to better characterize memory dysfunction following chemotherapy treatments. Given the importance of episodic and autobiographical memory to a person’s personal history and quality of life, an under-appreciation of how this memory domain is impacted by standard cancer treatments potentially diminishes the negative experiences of breast cancer survivors, and neglects cognitive problems that could benefit from intervention strategies.

Abstract

Long-term memory disturbances are amongst the most common and disruptive cognitive symptoms experienced by breast cancer survivors following chemotherapy. To date, most clinical assessments of long-term memory dysfunction in breast cancer survivors have utilized basic verbal and visual memory tasks that do not capture the complexities of everyday event memories. Complex event memories, including episodic memory and autobiographical memory, critically rely on hippocampal processing for encoding and retrieval. Systemic chemotherapy treatments used in breast cancer commonly cause neurotoxicity within the hippocampus, thereby creating a vulnerability to memory impairment. We review structural and functional neuroimaging studies that have identified disruptions in the recollection network and related episodic memory impairments in chemotherapy-treated breast cancer survivors, and argue for the need to better characterize hippocampally mediated memory dysfunction following chemotherapy treatments. Given the importance of autobiographical memory for a person’s sense of identity, ability to plan for the future, and general functioning, under-appreciation of how this type of memory is impacted by cancer treatment can lead to overlooking or minimizing the negative experiences of breast cancer survivors, and neglecting a cognitive domain that may benefit from intervention strategies.

Brain morphological alterations and their correlation to tumor differentiation and duration in patients with lung cancer after platinum chemotherapy

Objective

Chemotherapy-related brain impairments and changes can occur in patients with lung cancer after platinum chemotherapy and have a substantial impact on survivors’ quality of life. Therefore, it is necessary to understand the brain neuropathological alterations and response mechanisms to provide a theoretical basis for rehabilitation strategies. This study aimed to investigate the related brain morphological changes and clarified their correlation with clinical and pathological indicators in patients with lung cancer after platinum chemotherapy.

Methods

Overall, 28 patients with chemotherapy, 56 patients without chemotherapy, and 41 healthy controls were categorized in three groups, matched for age, sex, and years of education, and included in the cross-sectional comparison of brain volume and cortical thickness. 14 matched patients before and after chemotherapy were subjected to paired comparison for longitudinal observation of brain morphological changes. Three-dimensional T1-weighted images were acquired from all participants, and quantitative parameters were calculated using the formula of the change from baseline. Correlation analysis was performed to evaluate the relationship between abnormal morphological indices and clinical information of patients.

Results

Brain regions with volume differences among the three groups were mainly distributed in frontal lobe and limbic cortex. Additionally, significant differences in cerebrospinal fluid were observed in most ventricles, and the main brain regions with cortical thickness differences were the gyrus rectus and medial frontal cortex of the frontal lobe, transverse temporal gyrus of the temporal lobe, insular cortex, anterior insula, and posterior insula of the insular cortex. According to the paired comparison, decreased brain volumes in the patients after chemotherapy appeared in some regions of the frontal, parietal, temporal, and occipital lobes; limbic cortex; insular cortex; and lobules VI-X and decreased cortical thickness in the patients after chemotherapy was found in the frontal, temporal, limbic, and insular cortexes. In the correlation analysis, only the differentiation degree of the tumor and duration after chemotherapy were significantly correlated with imaging indices in the abnormal brain regions.

Conclusions

Our findings illustrate the platinum-related brain reactivity morphological alterations which provide more insights into the neuropathological mechanisms of patients with lung cancer after platinum chemotherapy and empirical support for the details of brain injury related to cancer and chemotherapy.

Longitudinal Trajectories of Memory Performance in Patients with Early-Stage Breast Cancer

Background. While breast cancer and its treatments may affect cognition, the longitudinal trajectories of cognition among those receiving differing cancer treatment types remain poorly understood. Prior research suggests hippocampal-prefrontal cortex network integrity may influence cognition, although how this network predicts performance over time remains unclear. Methods. We conducted a prospective trial including 69 patients with early-stage breast cancer receiving adjuvant therapy and 12 controls. Longitudinal cognitive testing was conducted at four visits: pretreatment-baseline, 6-7 months, 14-15 months, and 23-24 months. Cognitive composite scores of episodic memory, executive functioning, and processing speed were assessed at each timepoint. Baseline structural MRI was obtained in a subset of these participants, and hippocampal and prefrontal cortex regional volumes were extracted. Results. Longitudinal linear mixed modeling revealed significant group by time interactions on memory performance, controlling for age and education. Post hoc analyses revealed this effect was driven by patients treated with chemotherapy or chemotherapy plus hormone therapy, who demonstrated the least improvement in memory scores over time. Treatment group did not significantly influence the relationship between time and processing speed or executive functioning. Neither pretreatment hippocampal nor prefrontal volume differed between groups, and there were no significant group by time by baseline regional volume effects on cognition. Conclusion. Patients with early-stage breast cancer treated with chemotherapy or chemotherapy plus hormone therapy benefit less from practice effects seen in healthy controls on memory tests. Loss of longitudinal practice effect may be a new and clinically relevant measure for capturing patients’ experience of cognitive difficulties after treatment.

Protocol for the Exercise, Cancer and Cognition - The ECCO-Study: A Randomized Controlled Trial of Simultaneous Exercise During Neo-/Adjuvant Chemotherapy in Breast Cancer Patients and Its Effects on Neurocognition

Introduction

Epidemiological studies show that increased physical activity is linked to a lower risk of breast cancer and mortality. As a result, physical activity can significantly improve patients' quality of life (QOL) both during and after therapy.Many breast cancer patients demonstrate a decrease in cognitive capacity, referred to as the symptom-complex cancer related cognitive impairment (CRCI). Most frequently reported impairments are mild to moderate deficits in processing speed, attention, memory, and executive functions. Cognitive symptoms persist for months or even years, following medical treatment in roughly 35% of afflicted people, impairing everyday functioning, limiting the ability to return to work, and lowering the overall QOL. Recent studies point toward a key role of inflammatory pathways in the CRCI genesis. Attention to physical activity as a potential supportive care option is therefore increasing. However, evidence for the positive effects of exercise on preventing CRCI is still lacking.

Patients and Methods

Against this background, the prospective, two-arm, 1:1 randomized, controlled trial investigates the influence of first line chemotherapy accompanied by exercise training on preventing CRCI in 126 patients with breast cancer at the local University Hospital. The study will evaluate biomarkers and secondary assessments suspected to be involved in the pathogenesis of CRCI in addition to objective (primary outcome) and subjective cognitive function. CRCI is believed to be connected to either functional and/or morphological hippocampal damage due to chemotherapy. Thus, cerebral magnetic resonance imaging (MRI) and hippocampal volume measurements are performed. Furthermore, a specific neuropsychological test battery for breast cancer patients has been developed to detect early signs of cognitive impairments in patients and to be integrated into practice.

Discussion

This study will explore how a long-term supervised exercise intervention program might prevent CRCI, enables optimization of supportive care and objectifies limits of psychological and physical resilience in breast cancer patients during and after chemotherapy treatment.

Trial Registration

ClinicalTrials.gov: Identifier: NCT04789187. Registered on 09 March 2021.

Blood and neuroimaging biomarkers of cognitive sequelae in breast cancer patients throughout chemotherapy: A systematic review

Breast cancer treatment can induce alterations in blood- and neuroimaging-based markers. However, an overview of the predictive value of these markers for cognition is lacking for breast cancer survivors. This systematic review summarized studies of the last decade, using the PubMed database, evaluating blood markers, and the association between blood- or structural neuroimaging markers and cognition across the chemotherapy trajectory for primary breast cancer, following PRISMA guidelines. Forty-four studies were included. Differences were observed in all blood marker categories, from on-therapy until years post-chemotherapy. Associations were found between cognitive functioning and (1) blood markers (mainly inflammation-related) during, shortly-, or years post-chemotherapy and (2) white and gray matter metrics in frontal, temporal and parietal brain regions months up until years post-chemotherapy. Preliminary evidence exists for epigenetic and metabolic changes being associated with cognition, only after chemotherapy. This review demonstrated time-dependent associations between specific blood-based and structural neuroimaging markers with cognitive impairment in patients with breast cancer. Future studies are encouraged to include both neuroimaging- and blood markers (e.g. of neuronal integrity, epigenetics and metabolism) to predict long-term cognitive effects of chemotherapy.

Chemotherapy-Induced Cognitive Impairment and Hippocampal Neurogenesis: A Review of Physiological Mechanisms and Interventions

A wide range of cognitive deficits, including memory loss associated with hippocampal dysfunction, have been widely reported in cancer survivors who received chemotherapy. Changes in both white matter and gray matter volume have been observed following chemotherapy treatment, with reduced volume in the medial temporal lobe thought to be due in part to reductions in hippocampal neurogenesis. Pre-clinical rodent models confirm that common chemotherapeutic agents used to treat various forms of non-CNS cancers reduce rates of hippocampal neurogenesis and impair performance on hippocampally-mediated learning and memory tasks. We review the pre-clinical rodent literature to identify how various chemotherapeutic drugs affect hippocampal neurogenesis and induce cognitive impairment. We also review factors such as physical exercise and environmental stimulation that may protect against chemotherapy-induced neurogenic suppression and hippocampal neurotoxicity. Finally, we review pharmacological interventions that target the hippocampus and are designed to prevent or reduce the cognitive and neurotoxic side effects of chemotherapy.

Postchemotherapy hippocampal functional connectivity patterns in patients with breast cancer: a longitudinal resting state functional MR imaging study

The hippocampus plays a key role in cognitive function and emotion regulation due to its wide connection with the whole brain. This study examined the acute effect of chemotherapy on hippocampal and subfield functional connectivity and neuropsychological status in breast cancer patients (BC). This IRB approved study included 29 BC and 25 age matched healthy controls (HCs) who underwent resting state functional magnetic resonance imaging (Rs-fMRI), neuropsychological tests and blood examinations at baseline and one week after completing chemotherapy or in the same time interval. Within-group comparisons and group-by-time interactions analysis of hippocampus- and subregion- based functional connectivity were performed between the two groups. Functional connectivity changes were correlated with changes of blood examination and neuropsychological test scores in the BC group. The BC group had higher depression and anxiety scores, poorer performance on visual mobility, auditory memory and executive function than HCs (p < 0.05), and significantly abnormal estrodiol, total cholesterol and triglycerides (p < 0.05). BC survivors showed significant hippocampal functional connectivity changes mainly in the left insula, temporal lobe (Gaussian Random Field theory correction, P < 0.001) and the left inferior frontal gyrus (P < 0.01). The functional connections from the anterior hippocampus to the left temporal lobe were greater than the posterior hippocampus (P < 0.05). The hippocampus functional connectivity alterations were closely related to changes in depression scores, estrodiol and triglycerides (all p < 0.05). Chemotherapy induced especially anterior hippocampal functional connectivity abnormality, which is related to depression symptom, estrodiol and triglycerides disorders.

Cognitive complications of cancer and cancer-related treatments - Novel paradigms

As advances in diagnostics and therapeutic strategies in oncology have increased the number of cancer survivors, the investigation of the mechanisms associated with long-term cognitive complications of cancer treatment has become an important topic of interest. The neurotoxic effects of chemotherapeutic agents have been described in pre-clinical and clinical research. In vitro and rodent studies have identified some underlying mechanisms contributing to chemotherapy-induced neurotoxicity and cognitive impairment for various chemotherapy drugs and other cancer treatments. However, investigation of the direct biological effects of cancer and other potential contributing factors in the pathogenesis of cancer-related cognitive impairment (CRCI) has only recently come into focus. This review will highlight evidence from pre-clinical tumor-bearing rodent models suggesting that cancer influences the cognitive and behavioral changes reported in human cancer populations through direct or indirect pathways that alter the normal neuroinflammatory responses, induce structural brain deficits, and decrease neurogenesis. We reflect on human clinical cancer research indicating that cognitive and behavioral changes precede cancer treatment in some malignancies. We also highlight implications for future areas of CRCI research based on novel findings on the interplay between cancer, chemotherapy, inflammation, tau pathology, and dysregulation of the microbiota-gut-brain axis.

Measuring Self-Reported Cancer-Related Cognitive Impairment: Recommendations From the Cancer Neuroscience Initiative Working Group

Cancer and its treatments are associated with increased risk for cancer-related cognitive impairment (CRCI). Methods and measures used to study and assess self-reported CRCI (sr-CRCI), however, remain diverse, resulting in heterogeneity across studies. The Patient-Reported Outcomes Working Group has been formed to promote homogeneity in the methods used to study sr-CRCI. In this report, using a psychometric taxonomy, we inventory and appraise instruments used in research to measure sr-CRCI, and we consider advances in patient-reported outcome methodology. Given its psychometric properties, we recommend the Patient-Reported Outcome Measurement Information System Cognitive Function Short Form 8a for measurement of sr-CRCI in cancer patients and survivors, at a minimum, to increase scientific rigor and progress in addressing CRCI.

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

Background

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

Methods

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

Results

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

Conclusions

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

Social enrichment attenuates chemotherapy induced pro-inflammatory cytokine production and affective behavior via oxytocin signaling

Breast cancer survivors receiving chemotherapy often report increased anxiety and depression. However, the mechanism underlying chemotherapy-induced changes in affect remains unknown. We hypothesized that chemotherapy increases cytokine production, in turn altering exploratory and depressive-like behavior. To test this hypothesis, female Balb/C mice received two injections, separated by two weeks, of vehicle (0.9% saline) or a chemotherapeutic cocktail [9 mg/kg doxorubicin (A) and 90 mg/kg cyclophosphamide (C)]. Peripheral and central cytokine concentrations were increased one and seven days, respectively, after AC. Because of the beneficial effects of social enrichment on several diseases with inflammatory components, we examined whether social enrichment could attenuate the increase in peripheral and central cytokine production following chemotherapy administration. Socially isolated mice receiving AC therapy demonstrated increased depressive-like and exploratory behaviors with a concurrent increase in hippocampal IL-6. Whereas, group housing attenuated AC-induced IL-6 and depressive-like behavior. Next, we sought to determine whether central oxytocin may contribute to the protective effects of social housing after AC administration. Intracerebroventricular administration of oxytocin to socially isolated mice recapitulated the protective effects of social enrichment; specifically, oxytocin ameliorated the AC-induced effects on IL-6 and depressive-like behavior. Furthermore, administration of an oxytocin antagonist to group housed mice recapitulated the responses of socially isolated mice; specifically, AC increased depressive-like behavior and central IL-6. These data suggest a possible neuroprotective role for oxytocin following chemotherapy, via modulation of IL-6. This study adds to the growing literature detailing the negative behavioral effects of chemotherapy and provides further evidence that social enrichment may be beneficial to health.

The microbiota-gut-brain axis: An emerging therapeutic target in chemotherapy-induced cognitive impairment

Chemotherapy-induced cognitive impairment (CICI) is an ill-defined complication of chemotherapy treatment that places a significant psychosocial burden on survivors of cancer and has a considerable impact on the activities of daily living. CICI pathophysiology has not been clearly defined, with candidate mechanisms relating to both the direct cytotoxicity of chemotherapy drugs on the central nervous system (CNS) and more global, indirect mechanisms such as neuroinflammation and blood brain barrier (BBB) damage. A growing body of research demonstrates that changes to the composition of the gastrointestinal microbiota is an initiating factor in numerous neurocognitive conditions, profoundly influencing both CNS immunity and BBB integrity. Importantly, chemotherapy causes significant disruption to the gastrointestinal microbiota. While microbial disruption is a well-established factor in the development of chemotherapy-induced gastrointestinal toxicities (largely diarrhoea), its role in CICI remains unknown, limiting microbial-based therapeutics or risk prediction strategies. Therefore, this review aims to synthesise and critically evaluate the evidence addressing the microbiota-gut-brain axis as a critical factor influencing the development of CICI.

The Developmental Trajectory of Cancer-Related Cognitive Impairment in Breast Cancer Patients: A Systematic Review of Longitudinal Neuroimaging Studies

This systematic review explored the neurobiological mechanisms underlying the clinical time course of cancer-related cognitive impairment (CRCI) in breast cancer patients through the review of longitudinal neuroimaging studies. Before chemotherapy, results reported no evidence for neuropsychological, structural (gray matter) and brain perfusion changes. However, functional brain alterations were evident and revealed a frontoparietal hyperactivation during working memory tasks. Fatigue and number of days since surgery were the two suggested confounding factors. Acutely after chemotherapy, this review found no evidence for neuropsychological changes while suggesting a pattern of frontal structural, perfusion and functional brain abnormalities. These findings seemed to be dependent on age, menopausal status at baseline, and fMRI task performed. Years after chemotherapy, results revealed evidence of partial neuropsychological, structural, and functional brain recovery. Regarding brain abnormality, this review suggested that it may begin quite early in the disease course, be more prominent shortly after chemotherapy and partially recover over time. Several hypotheses underlying these changes were discussed. The present review also provided important information for developing a time-specific treatment and prevention strategies and for the consideration of functional neuroimaging as a relevant tool for CRCI diagnosis, clinical monitoring, and intervention studies. The findings also suggested the need to implement studies with longitudinal designs, including a pre-treatment assessment, since cross-sectional studies were not able to detect this pattern of recovery over time, supporting only the theory of brain abnormalities, in breast cancer survivors.

Dynamic Changes in EEG Power Spectral Densities During NIH-Toolbox Flanker, Dimensional Change Card Sort Test and Episodic Memory Tests in Young Adults

Much is known about electroencephalograph (EEG) patterns during sleep, but until recently, it was difficult to study EEG patterns during conscious, awake behavior. Technological advances such as powerful wireless EEG systems have led to a renewed interest in EEG as a clinical and research tool for studying real-time changes in the brain. We report here the first normative study of EEG activity while healthy young adults completed a series of cognitive tests recently published by the National Institutes of Health Toolbox Cognitive Battery (NIH-TCB), a commonly-used standardized measure of cognition primarily used in clinical populations. In this preliminary study using a wireless EEG system, we examined power spectral density (PSD) in four EEG frequency bands. During baseline and cognitive testing, PSD activity for the lower frequency bands (theta and alpha) was greater, relative to the higher frequency bands (beta and gamma), suggesting participants were relaxed and mentally alert. Alpha, beta and gamma activity was increased during a memory test compared to two other, less demanding executive function tests. Gamma activity was also inversely correlated with performance on the memory test, consistent with the neural efficiency hypothesis which proposes that better cognitive performance may link with lower cortical energy consumption. In summary, our study suggests that cognitive performance is related to the dynamics of EEG activity in a normative young adult population.

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

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

Hippocampus-Related Cognitive and Affective Impairments in Patients With Breast Cancer-A Systematic Review

Background: Although improvements in medical treatment lead to a steadily rising survival rate of breast cancer patients (BCP), it is associated with a decrease in cognitive and affective function. The hippocampus, a brain region with a high influence on both cognitive and affective function, is increasingly becoming the focus of current research because of its high vulnerability to adverse direct (chemotherapeutic agents, endocrine therapeutic agents, and radiation) or indirect (stress and other psycho-social factors) treatment-related effects.

Methods: This systematic review analyses current data from literature combining hippocampus-related brain changes due to breast cancer treatment with associated cancer-related cognitive and affective impairments (CRCI/CRAI). The seven studies that met the inclusion criteria consisted of six cross-sectional studies and one longitudinal study.

Results: The study results indicate hippocampal differences across all types of treatment. Those differences include volume loss, deformation, and changes in functional connectivity. They are associated with CRCI, revealing executive function as well as working memory, episodic memory, and prospective memory as the most affected domains. Although an interaction between hippocampus-related brain changes, CRCI, and CRAI can be hypothesized, CRAI are less reflected in current research.

Discussion: More research including longitudinal assessments with better overall methodology is needed to fully understand the interaction between hippocampal alterations and both CRCI and CRAI due to breast cancer treatment.

Preliminary examination of the validity of the NIH toolbox cognition battery in treatment-resistant psychosis

Objective: Prior research has suggested that treatment-resistant psychosis (TRP) may be a categorically distinct subtype from treatment-responsive psychotic disorders. However, relatively few studies have investigated the cognitive profile of individuals with TRP. Moreover, no prior studies have investigated the effectiveness of using the NIH Toolbox Cognition Battery (NTCB) for assessing cognition among psychiatric inpatients despite its promising efficiency and practicality in such settings. The current study aimed to investigate the validity of the NTCB and the associated cognitive profile of inpatients with TRP.Methods: Participants (N = 38) were administered the NTCB and a neuropsychological test battery. The Positive and Negative Syndrome Scale and the Routine Assessment of Patient Progress measured psychosis symptomatology and daily functioning, respectively.Results: Results showed deficits relative to normative values in fluid cognitive abilities using the NTCB, as predicted. There was strong convergent validity and adequate divergent validity between the NTCB subtests and corresponding neuropsychological measures, though no NTCB subtest correlated with performance on the Wisconsin Card Sorting Task. NTCB performance correlated with positive and disorganized symptoms of psychosis as well as daily functioning.Conclusions: Taken together, the NTCB appears to be a relatively strong tool for cognitive screening among psychiatric inpatients and may be used to identify which patients might benefit from further neuropsychological evaluation.

Doxorubicin and cisplatin induced cognitive impairment: The possible mechanisms and interventions

Chemotherapy has significantly increased the number of cancer survivors. However, chemotherapy itself carries various adverse effects that limit the efficacy of treatment and quality of life of the cancer patients. Most patients who have received chemotherapy report some cognitive deficit characterized by dysfunction in memory, learning, concentration, and reasoning. The phenomenon of cognitive decline developed from chemotherapy treatment is referred to as chemotherapy-induced cognitive impairment (CICI) or chemobrain. The two most common cancers occurring worldwide are lung and breast cancer. The predominant chemotherapeutic drugs used to treat lung and breast cancer are doxorubicin and cisplatin. There is evidence to suggest that both drugs potentially induce chemobrain. The evidence around the proposed pathogenesis of chemobrain caused by these two drugs is inconsistent. Understanding the underlying mechanisms involved in the development of chemobrain would aid in the prevention or treatment of the adverse effects of chemotherapy on brain. This review will summarize and discuss controversial findings and possible mechanisms involved in the development of chemobrain and the interventions which could limit it from in vitro, in vivo, and clinical studies.

Neurobiological mechanisms underlying sex-related differences in stress-related disorders: Effects of neuroactive steroids on the hippocampus

Men and women differ in their vulnerability to a variety of stress-related illnesses, but the underlying neurobiological mechanisms are not well understood. This is likely due to a comparative dearth of neurobiological studies that assess male and female rodents at the same time, while human neuroimaging studies often don't model sex as a variable of interest. These sex differences are often attributed to the actions of sex hormones, i.e. estrogens, progestogens and androgens. In this review, we summarize the results on sex hormone actions in the hippocampus and seek to bridge the gap between animal models and findings in humans. However, while effects of sex hormones on the hippocampus are largely consistent in animals and humans, methodological differences challenge the comparability of animal and human studies on stress effects. We summarise our current understanding of the neurobiological mechanisms that underlie sex-related differences in behavior and discuss implications for stress-related illnesses.

Structural brain alterations following adult non-CNS cancers: a systematic review of the neuroimaging literature

Background: Cancer and cancer treatments may impact the brain through several pathways leading to cognitive impairment. Neuroimaging evidence has begun to elucidate the neurobiological underpinnings of cancer-related cognitive impairment. The aim of this paper was to systematically review available literature on structural brain alterations following adult non-central nervous system (CNS) cancers and associated treatments. Methods: This review followed PRISMA guidelines and was registered in PROSPERO (ID#107387). Comprehensive searches were conducted in June 2018 using PubMed and Web of Science. Inclusion criteria were English peer-reviewed journal articles of formal, controlled studies that examined structural neuroimaging outcomes in adult non-CNS cancer patients and survivors. Selected articles were assessed for quality and risk of bias using the National Institutes of Health Quality Assessment Tool for Observational Cohort and Cross-Sectional Studies. Results: Thirty-six publications of prospective and cross-sectional studies met inclusion criteria and were included. Structural brain alterations following cancer and its treatment were reported in a majority of the publications as evidenced by reduced global and local gray matter volumes, impaired white matter microstructural integrity, and brain network alterations. Structural alterations were most often evident when cancer-treated groups were compared with healthy controls, and more subtle when compared with cancer controls. Regarding the existence of pretreatment impairments, the evidence was equivocal. There was significant between-study heterogeneity in imaging analytical approaches and use of statistical adjustments. Over half reported associations with cognitive outcomes, though regions and associated cognitive domains were heterogeneous. Conclusions: Structural brain alterations following cancer and cancer treatments were reported in a majority of the reviewed studies. However, the extent of observed alterations depended on the choice of comparison groups. Methodological issues exist that will need to be addressed systematically to ensure the validity of findings. Large-scale prospective studies with extended assessment points are warranted to replicate and build upon initial findings.

Hippocampal functional connectivity is related to self-reported cognitive concerns in breast cancer patients undergoing adjuvant therapy

Nearly three out of four survivors experience Cancer-Related Cognitive Impairment (CRCI) for months or years following treatment. Both clinical and animal studies point to the hippocampus as a likely brain region affected in CRCI, however no previous study has investigated the functional connectivity of the hippocampus in CRCI. We compared hippocampal connectivity in cancer survivors and healthy controls and tested the relationship between functional connectivity differences and measures of objective and subjective cognition. Exploratory analysis of inflammatory markers was conducted in a small subset of participants as well. FMRI data were acquired during a memory task from 16 breast cancer survivors and 17 controls. The NIH Toolbox was used to assess cognitive performance and Neuro-QoL was used to measure self-reported cognitive concerns. Whole-brain group-level comparisons identified clusters with different connectivity to the hippocampus in survivors versus controls during task. Average connectivity was extracted from clusters of significant difference between the groups and correlated with cognitive performance and subjective report. Survivors performed worse on a test of episodic memory and reported greater cognitive concern than controls. Exploratory analysis found higher IL6 in cancer survivors compared to controls. Cancer survivors demonstrated higher connectivity of hippocampus with left cuneus, left lingual, left precuneus, and right middle prefrontal gyrus compared with controls. In survivors, higher task-related hippocampal-cortical connectivity was related to worse subjective measures of cognitive concern. Of the four significant clusters, higher connectivity of the precuneus with hippocampus was significantly associated with worse cognitive concern in survivors. The observed greater hippocampal-cortical connectivity in survivors compared to controls is the first reported fMRI biomarker of subjective concern, and may represent a compensatory response to cancer and its treatments. This compensation could explain, in part, the subjective feelings of cognitive impairment that were reported by survivors.

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Cancer survivors performed worse on a test of episodic memory and reported greater cognitive concern than controls

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Cancer survivors demonstrated significantly higher hippocampal-cortical connectivity

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Higher functional connectivity was associated with worse self-reported cognitive functioning in cancer survivors

Cognitive Effects of Cancer and Cancer Treatments

As the population of cancer survivors has grown into the millions, there has been increasing emphasis on understanding how the late effects of treatment affect survivors' ability to return to work/school, their capacity to function and live independently, and their overall quality of life. This review focuses on cognitive change associated with cancer and cancer treatments. Research in this area has progressed from a pharmacotoxicology perspective to a view of the cognitive change as a complex interaction of aspects of the treatment, vulnerability factors that increase risk for posttreatment cognitive decline, cancer biology, and the biology of aging. Methodological advances include the development of (a) measurement approaches that assess more fine-grained subcomponents of cognition based on cognitive neuroscience and (b) advanced statistical approaches. Conceptual issues that arise from this multidimensional perspective are described in relation to future directions, understanding of mechanisms, and development of innovative interventions.

THE CREATIVE PSYCHOSOCIAL GENOMIC HEALING EXPERIENCE (CPGHE) AND GENE EXPRESSION IN BREAST CANCER PATIENTS: A FEASIBILITY STUDY

BACKGROUND

Biomarkers associated with inflammation and immune function are increasingly being used to examine mechanisms of the effects of mind-body therapies. Less researched are biomarkers associated with cognitive and executive functioning in the study of mind-body therapy mechanisms and effects. This study explored the feasibility of recruiting breast cancer patients (BCPs) and implementation fidelity of participation in a research project utilizing the 4-stage Creative Psychosocial Genomic Healing Experience (CPGHE), a mind-body protocol that is theorized to create epigenetic effects via targeted psychological change in emotional triggers in coping with cancer.

METHODS

Eight BCPs were identified as eligible (stages I, II, III, early phases of treatment) and five consented to one of two intervention groups (allocated to a single session or two sessions of CPGHE). Blood draws were examined pre- and post- intervention for a stress/inflammation gene expression marker, Nuclear Factor kappa-B (NF-kB), and three markers associated with synaptic plasticity undergirding cognitive and executive functioning: Early Growth Response 1 (EGR1), activity-regulated cytoskeleton-associated protein (Arc), and brain-derived neurotrophic factor (BDNF).

RESULTS

One consented BCP dropped out due to illness. The remaining four adhered to the 4-stage CPGHE protocol and found the CPGHE experience beneficial. Blood samples for the gene expression results were collected and processed according to planned protocol without incident.

CONCLUSION

Implementing the CPGHE and achieving good adherence among a sample of BCPs is feasible. Processing of blood samples collected from BCPs for gene expression data is also feasible.