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

Melatonin mitigates cisplatin-induced cognitive impairment in rats and improves hippocampal dendritic spine density

Cisplatin-induced cognitive impairment (chemobrain) affects a considerable percentage of cancer patients and has no established pharmacological treatment. Chemobrain can be associated with neuroinflammation and oxidative stress. Melatonin, a pineal hormone, is known to have antioxidant, anti-inflammatory and neuroprotective potential. In this study, we investigated cisplatin-induced cognitive impairment in rats and whether melatonin can improve or reverse this impairment. Behavioral testing involved measuring working memory using the novel location recognition test (NLRT) under conditions of cisplatin or cisplatin + melatonin treatment, followed by the collection of rats' brains. The brains were subsequently stained with Golgi-Cox stain and then the hippocampus area CA3 of each one was examined, and dendritic spine density was calculated. Treatment with cisplatin resulted in deficits in the rats' performance in the NLRT (P < 0.05). These deficits were prevented by the coadministration of melatonin (P < 0.05). Cisplatin also reduced the density of dendritic spines in the hippocampus (P < 0.0001), specifically CA3 area, while the coadministration of melatonin significantly reversed this reduction (P < 0.001). This study showed that melatonin can ameliorate cisplatin-induced spatial memory deficits and dendritic spines density abnormalities in rats. Given that melatonin is a safe and wildly used supplement, it is feasible to explore its use as a palliative intervention in cancer treatment.

Brain fog in central disorders of hypersomnolence: a review

Brain fog is an undefined term describing a cluster of symptoms related to fatigue and impaired memory, attention, and concentration. Brain fog or brain fog-like symptoms have been reported in central disorders of hypersomnolence and in a range of seemingly unrelated disorders, including coronavirus disease 2019, major depressive disorder, multiple sclerosis, lupus, and celiac disease. This narrative review summarizes current evidence and proposes a consensus definition for brain fog. Brain fog is prevalent in narcolepsy and idiopathic hypersomnia, with more than three-quarters of patients with either disorder reporting this symptom in a registry study; it has also been reported as particularly difficult to treat in idiopathic hypersomnia. Studies directly evaluating brain fog are rare; tools for evaluating this symptom cluster typically are patient reports, with few objective measures validated in any disorder. Evaluating brain fog is further complicated by confounding symptoms, such as excessive daytime sleepiness, which is a hallmark of hypersomnolence disorders. No treatments specifically address brain fog. The paucity of literature, assessment tools, and medications for brain fog highlights the need for research leading to better disambiguation and treatment. Until a clear consensus definition is established, we propose brain fog in hypersomnia disorders be defined as a cognitive dysfunction that may or may not be linked with excessive sleepiness, related to an underlying neuronal dysfunction, which reduces concentration and impairs information processing, leading to a complaint of lack of clarity of mental thinking and awareness.

CITATION

Rosenberg R, Thorpy MJ, Doghramji K, Morse AM. Brain fog in central disorders of hypersomnolence: a review. J Clin Sleep Med. 2024;20(4):643-651.

Deciphering the multifunctional role of dual leucine zipper kinase (DLK) and its therapeutic potential in disease

Dual leucine zipper kinase (DLK, MAP3K12), a serine/threonine protein kinase, plays a key role in neuronal development, as it regulates axon regeneration and degeneration through its downstream kinase. Importantly, DLK is closely related to the pathogenesis of numerous neurodegenerative diseases and the induction of β-cell apoptosis that leads to diabetes. In this review, we summarize the current understanding of DLK function, and then discuss the role of DLK signaling in human diseases. Furthermore, various types of small molecule inhibitors of DLK that have been published so far are described in detail in this paper, providing some strategies for the design of DLK small molecule inhibitors in the future.

Perioperative considerations in patients with chemotherapy-induced cognitive impairment: a narrative review

Patients with cancer may suffer from a decline in their cognitive function after various cancer therapies, including surgery, radiation, and chemotherapy, and in some cases, this decline in cognitive function persists even years after completion of treatment. Chemobrain or chemotherapy-induced cognitive impairment, a well-established clinical syndrome, has become an increasing concern as the number of successfully treated cancer patients has increased significantly. Chemotherapy-induced cognitive impairment can originate from direct neurotoxicity, neuroinflammation, and oxidative stress, resulting in alterations in grey matter volume, white matter integrity, and brain connectivity. Surgery has been associated with exacerbating the inflammatory response associated with chemotherapy and predisposes patients to develop postoperative cognitive dysfunction. As the proportion of patients living longer after these therapies increases, the magnitude of impact and growing concern of post-treatment cognitive dysfunction in these patients has also come to the fore. We review the clinical presentation, potential mechanisms, predisposing factors, diagnostic methods, neuropsychological testing, and imaging findings of chemotherapy-induced cognitive impairment and its intersection with postoperative cognitive dysfunction.

Toxic leukoencephalopathy with axonal spheroids caused by chemotherapeutic drugs other than methotrexate

BACKGROUND

The objective of this report is to share the clinicopathological features of chemotherapy-induced toxic leukoencephalopathy, which is a rare and under-recognized disease, clinically characterized by rapidly progressive cognitive loss that often leads to sudden death.

CASE PRESENTATION

A 64-year-old woman and a 63-year-old man, who had both suffered from a rapid deterioration of consciousness, were autopsied under the clinical impressions of either the central nervous system graft versus host disease (CNS-GVHD), infectious encephalitis, or autoimmune encephalitis. Both patients had been treated with multiple chemotherapy regimens, including adriamycin, cytarabine arabinoside, daunorubicin, fludarabine, azacitidine, and allogeneic peripheral blood stem cell transplantation to treat hematological malignancies (acute myelogenous leukemia and myelodysplastic syndrome). Neuropathological findings at autopsy revealed rarefaction and vacuolar changes of the white matter with axonal spheroids, reactive gliosis, and foamy macrophage infiltration, predominantly in the visual pathways of the occipital and temporal lobes. Damaged axons exhibited immunoreactivity to beta-amyloid, consistent with axonopathy. However, there was no lymphocyte infiltration that suggested CNS-GVHD or any type of encephalitis.

CONCLUSION

The neuropathology found in the presented cases had the characteristic features of toxic leukoencephalopathy (chemobrain). Our cases showed that toxic leukoencephalopathy can also be caused by chemotherapy drugs other than methotrexate.

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.

Mapping cognitive deficits in cancer patients after chemotherapy: An Activation Likelihood Estimation meta-analysis of task-related fMRI studies

Recent neuroimaging studies have reported alterations in brain activation during cognitive tasks in cancer patients who have undergone chemotherapy treatment. However, the location of these altered brain activation patterns after chemotherapy varies considerably across studies. The aim of the present meta-analysis was to quantitatively synthesise this body of evidence using Activation Likelihood Estimation to identify reliable regions of altered brain activation in cancer patients treated with chemotherapy, compared to healthy controls and no chemotherapy controls. Our systematic search identified 12 studies that adopted task-related fMRI on non-central nervous system cancer patients who received chemotherapy relative to controls. All studies were included in the analyses and were grouped into four contrasts. Cancer patients treated with chemotherapy showed reduced activation in the left superior parietal lobe/precuneus (family-wise error corrected p < .05) compared to no chemotherapy controls. No significant clusters were found in three of our contrasts. The majority of studies did not support an association between altered brain activation and cognitive performance after chemotherapy. Findings point towards a possible chemotherapy-induced alteration, which could inform targeted treatment strategies. With continued work in this field using homogenous task-related protocols and cancer populations, fMRI may be used as a biomarker of cognitive deficits in the future.

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

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

Age-related differences in self-report and objective measures of cognitive function in older patients prior to chemotherapy

Aim

Evaluate for differences in demographic and clinical characteristics and subjective and objective measures of cognitive function (CF) between younger older adults (YOA, 60–69 years) and older adults (OA, ≥70 years).

Design

Cross‐sectional.

Methods

Older oncology patients (n = 139) completed subjective (Attentional Function Index, European Organization for the Research and Treatment of Cancer Quality of Life Questionnaire (EORTC) CF scale) and objective (Montreal Cognitive Assessment, Trail Making Test (TMT) A & B) measures of CF prior to chemotherapy. Data were analyzed using parametric and nonparametric tests.

Results

No differences were found between the two groups for any of the subjective or objective CF measures, except that OA patients had higher TMT B scores. Compared with the general population, OAs had significantly higher EORTC CF scores and YOAs had significantly worse scores for all of the objective tests. Clinically meaningful difference between group differences was found for the TMT B test.

Four decades of chemotherapy-induced cognitive dysfunction: comprehensive review of clinical, animal and in vitro studies, and insights of key initiating events

Cognitive dysfunction has been one of the most reported and studied adverse effects of cancer treatment, but, for many years, it was overlooked by the medical community. Nevertheless, the medical and scientific communities have now recognized that the cognitive deficits caused by chemotherapy have a strong impact on the morbidity of cancer treated patients. In fact, chemotherapy-induced cognitive dysfunction or 'chemobrain'  (also named also chemofog) is at present a well-recognized effect of chemotherapy that could affect up to 78% of treated patients. Nonetheless, its underlying neurotoxic mechanism is still not fully elucidated. Therefore, this work aimed to provide a comprehensive review using PubMed as a database to assess the studies published on the field and, therefore, highlight the clinical manifestations of chemobrain and the putative neurotoxicity mechanisms.In the last two decades, a great number of papers was published on the topic, mainly with clinical observations. Chemotherapy-treated patients showed that the cognitive domains most often impaired were verbal memory, psychomotor function, visual memory, visuospatial and verbal learning, memory function and attention. Chemotherapy alters the brain's metabolism, white and grey matter and functional connectivity of brain areas. Several mechanisms have been proposed to cause chemobrain but increase of proinflammatory cytokines with oxidative stress seem more relevant, not excluding the action on neurotransmission and cellular death or impaired hippocampal neurogenesis. The interplay between these mechanisms and susceptible factors makes the clinical management of chemobrain even more difficult. New studies, mainly referring to the underlying mechanisms of chemobrain and protective measures, are important in the future, as it is expected that chemobrain will have more clinical impact in the coming years, since the number of cancer survivors is steadily increasing.

Inhibition of dual leucine zipper kinase prevents chemotherapy-induced peripheral neuropathy and cognitive impairments

ABSTRACT

Chemotherapy-induced peripheral neuropathy (CIPN) and chemotherapy-induced cognitive impairments (CICI) are common, often severe neurotoxic side effects of cancer treatment that greatly reduce quality of life of cancer patients and survivors. Currently, there are no Food and Drug Administration-approved agents for the prevention or curative treatment of CIPN or CICI. The dual leucine zipper kinase (DLK) is a key mediator of axonal degeneration that is localized to axons and coordinates the neuronal response to injury. We developed a novel brain-penetrant DLK inhibitor, IACS'8287, which demonstrates potent and highly selective inhibition of DLK in vitro and in vivo. Coadministration of IACS'8287 with the platinum derivative cisplatin prevents mechanical allodynia, loss of intraepidermal nerve fibers in the hind paws, cognitive deficits, and impairments in brain connectivity in mice, all without interfering with the antitumor activity of cisplatin. The protective effects of IACS'8287 are associated with preservation of mitochondrial function in dorsal root ganglion neurons and in brain synaptosomes. In addition, RNA sequencing analysis of dorsal root ganglia reveals modulation of genes involved in neuronal activity and markers for immune cell infiltration by DLK inhibition. These data indicate that CIPN and CICI require DLK signaling in mice, and DLK inhibitors could become an attractive treatment in the clinic when coadministered with cisplatin, and potentially other chemotherapeutic agents, to prevent neurotoxicities as a result of cancer treatment.

Chemotherapy-Related Differences in Cognitive Functioning and Their Biological Predictors in Patients with Multiple Myeloma

The paper presents a study on the changes in cognitive functioning in patients undergoing chemotherapy with diagnosed multiple myeloma (MM). The aim of the study was to answer the following two main research questions: Does the treatment stage differentiate the functioning of cognitive processes in patients with diagnosed MM and to what extent? Is it possible to treat biological factors (TNF-α, IL-6, IL-10, and BDNF) as predictors of patients' cognitive functioning? The patients were examined twice, before the treatment and after 4-6 cycles of chemotherapy. Selected neuropsychological research methods as well as experimental and clinical trials were employed to diagnose the patients' general cognitive state, attention, memory, and executive functions. The level of biological factors was assessed with the ELISA test. The results show that the patients' cognitive functioning was worse before the treatment than during the cytostatic therapy. It was also possible to predict the cognitive state of patients suffering from multiple myeloma based on a selected biological parameter (neurotrophin BDNF).

Chemo-brain: An activation likelihood estimation meta-analysis of functional magnetic resonance imaging studies

Adults with non-central nervous system (CNS) cancers frequently report problems in attention, memory and executive function during or after chemotherapy, referred to as cancer-related cognitive dysfunction (CRCD). Despite numerous studies investigating CRCD, there is no consensus regarding the brain areas implicated. We sought to determine if there are brain areas that consistently show either hyper- or hypo-activation in people treated with chemotherapy for non-CNS cancer (Chemo+). Using activation likelihood estimation on brain coordinates from 14 fMRI studies yielding 25 contrasts from 375 Chemo+ and 429 chemotherapy-naive controls while they performed cognitive tasks, the meta-analysis yielded two significant clusters which are part of the frontoparietal attention network, both showing lower activation in Chemo+. One cluster peaked in the left superior parietal cortex, extending into precuneus, inferior parietal lobule, and angular gyrus. The other peaked in the right superior prefrontal areas, extending into inferior prefrontal cortex. We propose that these observed lower activations reflect a dysfunction in mobilizing and/or sustaining attention due to depletion of cognitive resources. This could explain higher level of mental fatigue reported by Chemo+ and why cancer survivors report problems in a wide variety of cognitive domains.

Long-COVID syndrome-associated brain fog and chemofog: Luteolin to the rescue

COVID-19 leads to severe respiratory problems, but also to long-COVID syndrome associated primarily with cognitive dysfunction and fatigue. Long-COVID syndrome symptoms, especially brain fog, are similar to those experienced by patients undertaking or following chemotherapy for cancer (chemofog or chemobrain), as well in patients with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) or mast cell activation syndrome (MCAS). The pathogenesis of brain fog in these illnesses is presently unknown but may involve neuroinflammation via mast cells stimulated by pathogenic and stress stimuli to release mediators that activate microglia and lead to inflammation in the hypothalamus. These processes could be mitigated by phytosomal formulation (in olive pomace oil) of the natural flavonoid luteolin.

"Emotional Chemobrain": A new concept for chemotherapy adverse drug effect?

"Emotional chemobrain" is a new paradigm that relates the occurrence of alterations in the psychological wellbeing of patients to the adverse drug effects of chemotherapy on the neurobiological level. The concept of "emotional chemobrain" is the analogue concept of the classical concept of "chemobrain" but that concerns emotional disturbances related to chemotherapy. Disgust is a negative emotion that might accompany any stressful life event such as having cancer. Increased disgust may lead to the development of mental disorders such as mood and anxiety disorders. Patients with cancer may develop negative emotions such as self-disgust because of their affected autonomy and life style on the one hand and because of chemotherapy's effect on their brain on the other. Self-disgust might be considered as a factor contributing to psychological distress exacerbation in this category of physically ill individuals. In addition to lifestyle modifications and body changes, self-disgust might be exacerbated by chemotherapy in the same way other negative emotions might be exacerbated by this kind of treatment. It might be speculated that the emotional side effects of chemotherapy concern activation modifications in brain regions relevant to emotional elaboration and regulation such as the insular lobe and the amygdala. "Emotional chemobrain" should be considered whenever neuropsychiatric adverse effects of chemotherapy are manifested in patients with cancer. Future studies might be interested in studying the effect of chemotherapy on brain regions that can affect regulation of emotions such as self-disgust.

The Influence of Physical Activity and Epigenomics On Cognitive Function and Brain Health in Breast Cancer

The risk of breast cancer increases with age, with the majority of women diagnosed with breast cancer being postmenopausal. It has been estimated that 25-75% of women with breast cancer experience changes in cognitive function (CF) related to disease and treatment, which compromises psychological well-being, decision making, ability to perform daily activities, and adherence to cancer therapy. Unfortunately, the mechanisms that underlie neurocognitive changes in women with breast cancer remain poorly understood, which in turn limits the development of effective treatments and prevention strategies. Exercise has great potential as a non-pharmaceutical intervention to mitigate the decline in CF in women with breast cancer. Evidence suggests that DNA methylation, an epigenetic mechanism for gene regulation, impacts CF and brain health (BH), that exercise influences DNA methylation, and that exercise impacts CF and BH. Although investigating DNA methylation has the potential to uncover the biologic foundations for understanding neurocognitive changes within the context of breast cancer and its treatment as well as the ability to understand how exercise mitigates these changes, there is a dearth of research on this topic. The purpose of this review article is to compile the research in these areas and to recommend potential areas of opportunity for investigation.

The impact of neuroimaging advancement on neurocognitive evaluation in pediatric brain tumor survivors: A review

Pediatric brain tumors are a type of tumors that are commonly present in children and young adults. With the improvement of treatment, the quality of life, especially the cognitive functioning, is gaining increasingly more attention. Apart from cognitive evaluations, neuroimaging studies begin to play an important part in neurocognitive functioning investigation. In this way, the brain tissue changes caused by tumor variables (including tumor location and tumor size) and treatment variables (including surgery, chemotherapy and radiotherapy) can be detected by neuroimaging. Recent advancement of neuroimaging techniques, such as functional-MRI (fMRI) and diffusion tensor imaging (DTI), made great contributions to understanding cognitive dysfunction and quantifying the effects of tumor variables and treatment variables. In recent years, laminar-fMRI provided a potentially valuable tool for examining the exact origins of neural activity and cognitive function. On the other hand, molecular fMRI might guide diagnosis and treatment of brain disease in the future by using new biomarkers, and DTI can detect white matter changes and obtain some anatomically specific information.

Long-Term Clinical and Neuronuclear Imaging Sequelae of Cancer Therapy, Trauma, and Brain Injury

Neuronuclear imaging has been used for several decades in the study of primary neurodegenerative conditions, such as dementia and parkinsonian syndromes, both for research and for clinical purposes. There has been a relative paucity of applications of neuronuclear imaging to evaluate nonneurodegenerative conditions that can also have long-term effects on cognition and function. This article summarizes clinical and imaging aspects of 3 such conditions that have garnered considerable attention in recent years: cancer- and chemotherapy-related cognitive impairment, posttraumatic stress disorder, and traumatic brain injury. Further, we describe current research using neuroimaging tools aimed to better understand the relationships between the clinical presentations and brain structure and function in these conditions.

Role of Sonification and Rhythmic Auditory Cueing for Enhancing Gait Associated Deficits Induced by Neurotoxic Cancer Therapies: A Perspective on Auditory Neuroprosthetics

Patients undergoing chemotherapy, radiotherapy, and immunotherapy experience neurotoxic changes in the central and peripheral nervous system. These neurotoxic changes adversely affect functioning in the sensory, motor, and cognitive domains. Thereby, considerably affecting autonomic activities like gait and posture. Recent evidence from a range of systematic reviews and meta-analyses have suggested the beneficial influence of music-based external auditory stimulations i.e., rhythmic auditory cueing and real-time auditory feedback (sonification) on gait and postural stability in population groups will balance disorders. This perspective explores the conjunct implications of auditory stimulations during cancer treatment to simultaneously reduce gait and posture related deficits. Underlying neurophysiological mechanisms by which auditory stimulations might influence motor performance have been discussed. Prompt recognition of this sensorimotor training strategy in future studies can have a widespread impact on patient care in all areas of oncology.

Baseline Cognition Assessment Among Patients With Oropharyngeal Cancer Using PROMIS and NIH Toolbox

Importance

Cognitive dysfunction (CD) is recognized by the American Cancer Society as a treatment effect in head and neck cancer, but the extent of this problem at baseline in oropharyngeal cancer (OPC), the most common subsite in current practice, to our knowledge has never been studied.

Objective

To assess the baseline cognition of patients with OPC using National Institutes of Health (NIH)-sponsored instruments of Patient-Reported Outcomes Measurement Information System (PROMIS) and NIH Toolbox Cognitive Battery (NIHTB-CB).

Design, Setting, and Participants

This was a prospective cohort study conducted at a tertiary academic center. Of 83 consecutive patients, newly diagnosed as having OPC from September 2016 to May 2017, 16 were ineligible, 8 refused to participate, and 3 were lost to follow-up after screening, resulting in 56 study participants.

Main Outcomes and Measures

Self-perceived and objective cognition with PROMIS and NIHTB-CB standardized T scores, respectively, were main outcomes. Impairment was defined as (1) T scores less than 0.5 SD for PROMIS; (2) T score less than 1.5 SD in at least 1 cognitive domain or less than 1 SD in 2 or more domains for NIHTB-CB total cognition; and (3) T score per previously published criteria for NIHTB-CB intelligence-stratified cognition.

Results

Of the 56 study participants (52 men, 4 women; median age, 59 years [range, 42-77 years]), 19 (34%) had a college degree, and 20 (36%) had a professional or technical occupation. Thirty (about 53%) were never-smokers, 26 (46%) were never-drinkers, 29 (52%) were obese, 13 (23%) had a moderate to severe comorbidity, 3 (5%) used antidepressants, and 25 (52%) had hearing loss. Impaired self-reported, NIHTB-CB total, and intelligence-stratified cognition scores were observed in 6 (11%), 18 (32%), and 12 (21%), respectively. Among all variables, objective impairment was more common in men (23% vs 0%) and those with p16-negative OPC (33% vs 20%), moderate to severe comorbidity (31% vs 18%), and hearing loss (31% vs 12%).

Conclusions and Relevance

Impaired objective cognition was more common at baseline than self-reported, and was more frequent in men, participants with p16-negative OPC, moderate to severe comorbidity, and hearing loss. NIHTB-CB allowed immediate scoring of demographically adjusted cognitive function. In clinical practice, these scores can be used to identify patients with impaired cognition at baseline who may be susceptible to developing further impairment after treatment. Identification of impairment at baseline will help to institute early cognitive interventions, which may lead to an improved posttreatment quality of life.

Gray matter density reduction associated with adjuvant chemotherapy in older women with breast cancer

Purpose

The purpose of this study was to evaluate longitudinal changes in brain gray matter density (GMD) before and after adjuvant chemotherapy in older women with breast cancer.

Methods

We recruited 16 women aged ≥ 60 years with stage I–III breast cancers receiving adjuvant chemotherapy (CT) and 15 age- and sex-matched healthy controls (HC). The CT group underwent brain MRI and the NIH Toolbox for Cognition testing prior to adjuvant chemotherapy (time point 1, TP1) and within 1 month after chemotherapy (time point 2, TP2). The HC group underwent the same assessments at matched intervals. GMD was evaluated with the voxel-based morphometry.

Results

The mean age was 67 years in the CT group and 68.5 years in the HC group. There was significant GMD reduction within the chemotherapy group from TP1 to TP2. Compared to the HC group, the CT group displayed statistically significantly greater GMD reductions from TP1 to TP2 in the brain regions involving the left anterior cingulate gyrus, right insula, and left middle temporal gyrus (p_{FWE(family-wise error)-corrected} < 0.05). The baseline GMD in left insula was positively correlated with the baseline list-sorting working memory score in the HC group (p_{FWE-corrected} < 0.05). No correlation was observed for the changes in GMD with the changes in cognitive testing scores from TP1 to TP2 (p_{FWE-corrected} < 0.05).

Conclusions

Our findings indicate that GMD reductions were associated with adjuvant chemotherapy in older women with breast cancer. Future studies are needed to understand the clinical significance of the neuroimaging findings. This study is registered on ClinicalTrials.gov (NCT01992432).

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

Longitudinal assessment of chemotherapy-induced changes in brain and cognitive functioning: A systematic review

In addition to the burden of a life-threatening diagnosis, cancer patients are struggling with adverse side-effects from cancer treatment. Chemotherapy has been linked to an array of cognitive impairments and alterations in brain structure and function ("chemobrain"). In this review, we summarized the existing evidence that evaluate the changes in cognitive functioning and brain with chemotherapy, as assessed using structural and functional MRI-based techniques in a longitudinal design. This review followed the latest PRISMA guidelines using Embase, Medline, PsychINFO, Scopus, and Web of Science databases with date restrictions from 2012 to 2017. Fourteen research articles met the key inclusion criteria: (i) the studies involved adult cancer patients (mean age ≥ 18); (ii) the use of chemotherapy in the treatment of cancer; (iii) pre-post assessment of behavioral and brain-based outcomes; and (iv) abstracts written in English. Effect sizes of subjective and objective cognitive impairments from the reviewed studies were estimated using Cohen's d or z-scores. We calculated percentage of mean change or effect sizes for main neuroimaging findings when data were available. Strength of the correlations between brain alterations and cognitive changes was obtained using squared correlation coefficients. Small to medium effect sizes were shown? on individual tests of attention, processing speed, verbal memory, and executive control; and medium effect sizes on self-report questionnaires. Neuroimaging data showed reduced grey matter density in cancer patients in frontal, parietal, and temporal regions. Changes in brain function (brain activation and cerebral blood flow) were observed with cancer across functional networks involving (pre)frontal, parietal, occipital, temporal, and cerebellar regions. Data from diffusion-weighted MRI suggested reduced white matter integrity involving the superior longitudinal fasciculus, corpus callosum, forceps major, and corona radiate, and altered structural connectivity across the whole brain network. Finally, we observed moderate-to-strong correlations between worsening cognitive function and morphological changes in frontal brain regions. While MRI is a powerful tool for detection of longitudinal brain changes in the 'chemobrain', the underlying biological mechanisms are still unclear. Continued work in this field will hopefully detect MRI metrics to be used as biomarkers to help guide cognitive treatment at the individual cancer patient level.

A novel preventive therapy for paclitaxel-induced cognitive deficits: preclinical evidence from C57BL/6 mice

Chemotherapy-induced central nervous system (CNS) neurotoxicity presents an unmet medical need. Patients often report a cognitive decline in temporal correlation to chemotherapy, particularly for hippocampus-dependent verbal and visuo-spatial abilities. We treated adult C57Bl/6 mice with 12 × 20 mg kg^-1 paclitaxel (PTX), mimicking clinical conditions of dose-dense chemotherapy, followed by a pulse of bromodesoxyuridine (BrdU) to label dividing cells. In this model, mice developed visuo-spatial memory impairments, and we measured peak PTX concentrations in the hippocampus of 230 nm l^-1, which was sevenfold higher compared with the neocortex. Histologic analysis revealed a reduced hippocampal cell proliferation. In vitro, we observed severe toxicity in slowly proliferating neural stem cells (NSC) as well as human neuronal progenitor cells after 2 h exposure to low nanomolar concentrations of PTX. In comparison, mature post-mitotic hippocampal neurons and cell lines of malignant cells were less vulnerable. In PTX-treated NSC, we observed an increase of intracellular calcium levels, as well as an increased activity of calpain- and caspase 3/7, suggesting a calcium-dependent mechanism. This cell death pathway could be specifically inhibited with lithium, but not glycogen synthase kinase 3 inhibitors, which protected NSC in vitro. In vivo, preemptive treatment of mice with lithium prevented PTX-induced memory deficits and abnormal adult hippocampal neurogenesis. In summary, we identified a molecular pathomechanism, which invokes PTX-induced cytotoxicity in NSC independent of cell cycle status. This pathway could be pharmacologically inhibited with lithium without impairing paclitaxel's tubulin-dependent cytostatic mode of action, enabling a potential translational clinical approach.

Impact of immunoablation and autologous hematopoietic stem cell transplantation on gray and white matter atrophy in multiple sclerosis

Background:

Immunoablation and autologous hematopoietic stem cell transplantation (IA/aHSCT) halts relapses, white matter (WM) lesion formation, and pathological whole-brain (WB) atrophy in multiple sclerosis (MS) patients. Whether the latter was due to effects on gray matter (GM) or WM warranted further exploration.

Objective:

To model GM and WM volume changes after IA/aHSCT to further understand the effects seen on WB atrophy.

Methods:

GM and WM volume changes were calculated from serial baseline and follow-up magnetic resonance imaging (MRI) ranging from 1.5 to 10.5 years in 19 MS patients treated with IA/aHSCT. A mixed-effects model with two predictors (total busulfan dose and baseline T1-weighted WM lesion volume “T1LV”) characterized the time-courses after IA/aHSCT.

Results:

Accelerated short-term atrophy of 2.1% and 3.2% occurred in GM and WM, respectively, on average. Both busulfan dose and T1LV were significant predictors of WM atrophy, whereas only busulfan was a significant predictor of GM atrophy. Compared to baseline, a significant reduction in GM atrophy, not WM atrophy, was found. The average rates of long-term GM and WM atrophy were −0.18%/year (standard error (SE): 0.083) and −0.07%/year (SE: 0.14), respectively.

Conclusion:

Chemotherapy-related toxicity affected both GM and WM. WM was further affected by focal T1-weighted lesion-related pathologies. Long-term rates of GM and WM atrophy were comparable to those of normal-aging.

Review paper. Chemobrain in patients suffering from cancer based on the example of multiple myeloma

Introduction: The incidence rate of cancers emphasizes the necessity to investigate not only patients’ somatic ailments but also their psychosocial functioning as well as the need to raise the quality standards of cancer patients. The improvement of the quality of life is one of the major challenges of psycho-oncology, which is the science created in the interface of two disciplines: psychology and medicine.

One of the important aspects of psycho-oncologists’ activity is the minimization of negative side-effects related to treatment, such as changes in patients’ cognitive functioning resulting from anti-cancer treatment.

Objective: The aim of this work is to provide the reader with the knowledge concerning the phenomenon of chemobrain in a very special group of patients with hemato-oncologic tumour. Few researches related to this topic have confirmed the occurrence of cognitive deficits resulting from the cancer process, taken cytotoxic drugs, other forms of anti-cancer therapy and the activeness of biochemical compounds in patients with multiple myeloma.

Methods: The author has done a literary review concerning the topic under study using the Google Scholar and EBSCO databases. The main part of this work consists of references to Polish and English research literature published after 2000. The review includes also classic works from the eighties and nineties of the 20th century.

Results: The present work has been divided into several sections. The part devoted to explanation of the term chemobrain describes the evolution of its definition over the years. The second section - ‘Heterogeneity of the phenomenon - causes’ - underlines the influence of biochemical etiological factors, such as the impact of the activity of proinflammatory cytokines on the cognitive state of the patients suffering from tumour. Next part - ‘Chemobrain and multiple myeloma’ is devoted to the clinical characteristics of this cancer and to the descriptions of the selected methods of chemotherapy. The review of researches concerning the deteriorated cognitive functioning of patients with multiple myeloma in relation to the probable aetiology of this disease has been also presented.

Conclusions: The review of Polish and English literature concerning the functioning of memory and attention processes in the patients suffering from multiple myeloma can serve as an inspiration for a search for objective biochemical factors conditioning the deterioration of cognitive processes of the patients undergoing anti-cancer treatment.

A systemic literature review of neuroimaging studies in women with breast cancer treated with adjuvant chemotherapy

Chemotherapy-induced cognitive deficits in patients with breast cancer, predominantly in attention and verbal memory, have been observed in numerous studies. These neuropsychological findings are corroborated by the results of neuroimaging studies. The aim of this paper was to survey the reports on cerebral structural and functional alterations in women with breast cancer treated with chemotherapy (CTx). First, we discuss the host-related and disease-related mechanisms underlying cognitive impairment after CTx. We point out the direct and indirect neurotoxic effect of cytostatics, which may cause: a damage to neurons or glial cells, changes in neurotransmitter levels, deregulation of the immune system and/or cytokine release. Second, we focus on the results of neuroimaging studies on brain structure and function that revealed decreased: density of grey matter, integrity of white matter and volume of multiple brain regions, as well as their lower activation during cognitive task performance. Finally, we concentrate on compensatory mechanisms, which activate additional brain areas or neural connection to reach the premorbid cognitive efficiency.

Non-pharmacological interventions for cognitive impairment due to systemic cancer treatment

BACKGROUND

It is estimated that up to 75% of cancer survivors may experience cognitive impairment as a result of cancer treatment and given the increasing size of the cancer survivor population, the number of affected people is set to rise considerably in coming years. There is a need, therefore, to identify effective, non-pharmacological interventions for maintaining cognitive function or ameliorating cognitive impairment among people with a previous cancer diagnosis.

OBJECTIVES

To evaluate the cognitive effects, non-cognitive effects, duration and safety of non-pharmacological interventions among cancer patients targeted at maintaining cognitive function or ameliorating cognitive impairment as a result of cancer or receipt of systemic cancer treatment (i.e. chemotherapy or hormonal therapies in isolation or combination with other treatments).

SEARCH METHODS

We searched the Cochrane Centre Register of Controlled Trials (CENTRAL), MEDLINE, Embase, PUBMED, Cumulative Index of Nursing and Allied Health Literature (CINAHL) and PsycINFO databases. We also searched registries of ongoing trials and grey literature including theses, dissertations and conference proceedings. Searches were conducted for articles published from 1980 to 29 September 2015.

SELECTION CRITERIA

Randomised controlled trials (RCTs) of non-pharmacological interventions to improve cognitive impairment or to maintain cognitive functioning among survivors of adult-onset cancers who have completed systemic cancer therapy (in isolation or combination with other treatments) were eligible. Studies among individuals continuing to receive hormonal therapy were included. We excluded interventions targeted at cancer survivors with central nervous system (CNS) tumours or metastases, non-melanoma skin cancer or those who had received cranial radiation or, were from nursing or care home settings. Language restrictions were not applied.

DATA COLLECTION AND ANALYSIS

Author pairs independently screened, selected, extracted data and rated the risk of bias of studies. We were unable to conduct planned meta-analyses due to heterogeneity in the type of interventions and outcomes, with the exception of compensatory strategy training interventions for which we pooled data for mental and physical well-being outcomes. We report a narrative synthesis of intervention effectiveness for other outcomes.

MAIN RESULTS

Five RCTs describing six interventions (comprising a total of 235 participants) met the eligibility criteria for the review. Two trials of computer-assisted cognitive training interventions (n = 100), two of compensatory strategy training interventions (n = 95), one of meditation (n = 47) and one of physical activity intervention (n = 19) were identified. Each study focused on breast cancer survivors. All five studies were rated as having a high risk of bias. Data for our primary outcome of interest, cognitive function were not amenable to being pooled statistically. Cognitive training demonstrated beneficial effects on objectively assessed cognitive function (including processing speed, executive functions, cognitive flexibility, language, delayed- and immediate- memory), subjectively reported cognitive function and mental well-being. Compensatory strategy training demonstrated improvements on objectively assessed delayed-, immediate- and verbal-memory, self-reported cognitive function and spiritual quality of life (QoL). The meta-analyses of two RCTs (95 participants) did not show a beneficial effect from compensatory strategy training on physical well-being immediately (standardised mean difference (SMD) 0.12, 95% confidence interval (CI) -0.59 to 0.83; I(2)= 67%) or two months post-intervention (SMD - 0.21, 95% CI -0.89 to 0.47; I(2) = 63%) or on mental well-being two months post-intervention (SMD -0.38, 95% CI -1.10 to 0.34; I(2) = 67%). Lower mental well-being immediately post-intervention appeared to be observed in patients who received compensatory strategy training compared to wait-list controls (SMD -0.57, 95% CI -0.98 to -0.16; I(2) = 0%). We assessed the assembled studies using GRADE for physical and mental health outcomes and this evidence was rated to be low quality and, therefore findings should be interpreted with caution. Evidence for physical activity and meditation interventions on cognitive outcomes is unclear.

AUTHORS' CONCLUSIONS

Overall, the, albeit low-quality evidence may be interpreted to suggest that non-pharmacological interventions may have the potential to reduce the risk of, or ameliorate, cognitive impairment following systemic cancer treatment. Larger, multi-site studies including an appropriate, active attentional control group, as well as consideration of functional outcomes (e.g. activities of daily living) are required in order to come to firmer conclusions about the benefits or otherwise of this intervention approach. There is also a need to conduct research into cognitive impairment among cancer patient groups other than women with breast cancer.

The Role of Oxidative Stress in Etiopathogenesis of Chemotherapy Induced Cognitive Impairment (CICI)-"Chemobrain"

Chemobrain or chemotherapy induced cognitive impairment (CICI) represents a new clinical syndrome characterised by memory, learning and motor function impairment. As numerous patients with cancer are long-term survivors, CICI represent a significant factor which may interfere with their quality of life. However, this entity CICI must be distinguished from other cognitive syndromes and addressed accordingly. At the present time, experimental and clinical research suggests that CICI could be induced by numerous factors including oxidative stress. This type of CNS injury has been previously described in cancer patients treated with common anti-neoplastic drugs such as doxorubicine, carmustine, methotrexate and cyclophosphamide. It seems that all these pharmacological factors promote neuronal death through a final common pathway represented by TNF alpha (tumour necrosis factor). However, as cancer in general is diagnosed more commonly in the aging population, the elderly oncological patient must be treated with great care since aging per se is also impacted by oxidative stress and potentiually by TNF alpha deleterious action on brain parenchyma. In this context, some patients may develop cognitive dysfunction well before the appearance of CICI. In addition, chemotherapy may worsen their cognitive function. Therefore, at the present time, there is an acute need for development of effective therapeutic methods to prevent CICI as well as new methods of early CICI diagnosis.

Reduced prefrontal activation during working and long-term memory tasks and impaired patient-reported cognition among cancer survivors postchemotherapy compared with healthy controls

BACKGROUND

Patients who receive adjuvant chemotherapy have reported cognitive impairments that may last for years after the completion of treatment. Working memory-related and long-term memory-related changes in this population are not well understood. The objective of this study was to demonstrate that cancer-related cognitive impairments are associated with the under recruitment of brain regions involved in working and recognition memory compared with controls.

METHODS

Oncology patients (n = 15) who were receiving adjuvant chemotherapy and had evidence of cognitive impairment according to neuropsychological testing and self-report and a group of age-matched, education group-matched, cognitively normal control participants (n = 14) underwent functional magnetic resonance imaging. During functional magnetic resonance imaging, participants performed a nonverbal n-back working memory task and a visual recognition task.

RESULTS

On the working memory task, when 1-back and 2-back data were averaged and contrasted with 0-back data, significantly reduced activation was observed in the right dorsolateral prefrontal cortex for oncology patients versus controls. On the recognition task, oncology patients displayed decreased activity of the left-middle hippocampus compared with controls. Neuroimaging results were not associated with patient-reported cognition.

CONCLUSIONS

Decreased recruitment of brain regions associated with the encoding of working memory and recognition memory was observed in the oncology patients compared with the control group. These results suggest that there is a reduction in neural functioning postchemotherapy and corroborate patient-reported cognitive difficulties after cancer treatment, although a direct association was not observed. Cancer 2016;122:258-268. © 2015 American Cancer Society.

Frontal hypometabolism in elderly breast cancer survivors determined by [(18)F]fluorodeoxyglucose (FDG) positron emission tomography (PET): a pilot study

PURPOSE

The term "chemobrain" is sometimes used to denote deficits in neuropsychological functioning that may occur as a result of cancer treatment. As breast cancer survivors now commonly reach late life, it is not known whether previous exposure to chemotherapy may affect long-term risk for cognitive impairment. To help address this concern, this study tested whether successfully surviving chemotherapy earlier in life was associated with later differences in brain metabolic function as an older adult compared to controls. This question was examined using positron emission tomography measures of brain glucose metabolism in elderly women cancer survivors.

METHODS

Breast cancer survivors (N = 10), currently free of recurrent cancer and without a diagnosis of a cognitive disorder, were compared to matched healthy controls (N = 10). All subjects were imaged at rest with [(18)F]fluorodeoxyglucose. Images were analyzed semi-quantitatively using the Alzheimer's Discrimination Tool and a volume of interest-based approach derived from co-registered magnetic resonance imaging.

RESULTS

Relative [(18)F]fluorodeoxyglucose uptake (normalized to global) was significantly lower in the survivors compared with control subjects in bilateral orbital frontal regions, consistent with differences between the groups in cognition and executive function (i.e., Trail Making Test, Part B and mini-mental state examination) and despite no significant differences with respect to age, education, intelligence, or working memory. None of the survivors and only one control manifested a global positron emission tomography score consistent with an Alzheimer's disease metabolic pattern.

CONCLUSION

Breast cancer survivors treated with chemotherapy may manifest long-term changes in brain glucose metabolism indicative of subtle frontal hypometabolism, a finding consistent with results from neuropsychological testing and other imaging modalities.

Brain network alterations and vulnerability to simulated neurodegeneration in breast cancer

Breast cancer and its treatments are associated with mild cognitive impairment and brain changes that could indicate an altered or accelerated brain aging process. We applied diffusion tensor imaging and graph theory to measure white matter organization and connectivity in 34 breast cancer survivors compared with 36 matched healthy female controls. We also investigated how brain networks (connectomes) in each group responded to simulated neurodegeneration based on network attack analysis. Compared with controls, the breast cancer group demonstrated significantly lower fractional anisotropy, altered small-world connectome properties, lower brain network tolerance to systematic region (node), and connection (edge) attacks and significant cognitive impairment. Lower tolerance to network attack was associated with cognitive impairment in the breast cancer group. These findings provide further evidence of diffuse white matter pathology after breast cancer and extend the literature in this area with unique data demonstrating increased vulnerability of the post-breast cancer brain network to future neurodegenerative processes.

Default mode network as a potential biomarker of chemotherapy-related brain injury

Chronic medical conditions and/or their treatments may interact with aging to alter or even accelerate brain senescence. Adult onset cancer, for example, is a disease associated with advanced aging and emerging evidence suggests a profile of subtle but diffuse brain injury following cancer chemotherapy. Breast cancer is currently the primary model for studying these "chemobrain" effects. Given the widespread changes to brain structure and function as well as the common impairment of integrated cognitive skills observed following breast cancer chemotherapy, it is likely that large-scale brain networks are involved. Default mode network (DMN) is a strong candidate considering its preferential vulnerability to aging and sensitivity to toxicity and disease states. Additionally, chemotherapy is associated with several physiological effects including increased inflammation and oxidative stress that are believed to elevate toxicity in the DMN. Biomarkers of DMN connectivity could aid in the development of treatments for chemotherapy-related cognitive decline.

A prospective study of grey matter and cognitive function alterations in chemotherapy-treated breast cancer patients

PURPOSE

Subsequent to chemotherapy treatment, breast cancer patients often report a decline in cognitive functioning that can adversely impact many aspects of their lives. Evidence has mounted in recent years indicating that a portion of breast cancer survivors who have undergone chemotherapy display reduced performance on objective measures of cognitive functioning relative to comparison groups. Neurophysiological support for chemotherapy-related cognitive impairment has been accumulating due to an increase in neuroimaging studies in this field; however, longitudinal studies are limited and have not examined the relationship between structural grey matter alterations and neuropsychological performance. The aim of this study was to extend the cancer-cognition literature by investigating the association between grey matter attenuation and objectively measured cognitive functioning in chemotherapy-treated breast cancer patients.

METHODS

Female breast cancer patients (n = 19) underwent magnetic resonance imaging after surgery but before commencing chemotherapy, one month following treatment, and one year after treatment completion. Individually matched controls (n = 19) underwent imaging at similar intervals. All participants underwent a comprehensive neuropsychological battery comprising four cognitive domains at these same time points. Longitudinal grey matter changes were investigated using voxel-based morphometry.

RESULTS

One month following chemotherapy, patients had distributed grey matter volume reductions. One year after treatment, a partial recovery was observed with alterations persisting predominantly in frontal and temporal regions. This course was not observed in the healthy comparison group. Processing speed followed a similar trajectory within the patient group, with poorest scores obtained one month following treatment and some improvement evident one year post-treatment.

CONCLUSION

This study provides further credence to patient claims of altered cognitive functioning subsequent to chemotherapy treatment.

Systemically treated breast cancer patients and controls: an evaluation of the presence of noncredible performance

This study sought to define the frequency of noncredible performance in breast cancer patients before, during and after completion of systemic treatment, as well as predictors of noncredible performance. We examined six datasets investigating the cognitive effects of chemotherapy and/or endocrine therapy. Embedded performance validity test (PVT) measures were identified and used to evaluate the datasets. One dataset included a standalone PVT. Possible noncredible performance was operationally defined as performance below criterion on three or more PVT indices. This was undertaken as cancer patients have been observed clinically to fail PVTs both in the context of external gain and independent of such motivators. A total of 534 breast cancer patients and 214 healthy controls were included in the analysis. Percentages of patients performing below cutoff on one or more PVT varied from 0% to 21.2%. Only 1 patient met the criterion of noncredible performance. Calculation of post-test probabilities indicated a more than 90% chance to detect noncredible performance. There is no evidence to suggest noncredible performance in breast cancer patients and healthy controls who choose to participate in research studies examining cognitive function. Thus, the observational data showing that non-central nervous system (CNS) cancer and therapies not targeting the CNS can have untoward effects on cognitive function are unlikely to be due to noncredible performance.

Histological experimental study on the effect of stem cell therapy on adriamycin induced chemobrain

BACKGROUND AND OBJECTIVES

Negative consequences of chemotherapy on brain function were suggested and were addressed in animal models as the clinical phenomenon of chemobrain .It was postulated that adriamycin (ADR) induce changes in behaviour and in brain morphology. Human umbilical cord mesenchymal stem cells (HUCMSCs) could be induced to differentiate into neuron-like cells .The present study aimed at investigating the possible therapeutic effect of HUCMSC therapy on adriamycin induced chemobrain in rat.

METHODS AND RESULTS

Twenty five female albino rats were divided into control group, ADR group where rats were given single intraperitoneal (IP) injection of 5 mg/kg ADR. The rats were sacrificed two and four weeks following confirmation of brain damage. In stem cell therapy group, rats were injected with HUCMSCs following confirmation of brain damage and sacrificed two and four weeks after therapy. Brain sections were exposed to histological, histochemical, immunohistochemical and morphometric studies. In ADR group, multiple shrunken neurons exhibiting dark nuclei and surrounded by vacuoles were seen .In response to SC therapy ,multiple normal pyramidal nerve cells were noted. The area of shrunken nerve cells exhibiting dark nuclei, Prussion blue and CD105 positive cells were significantly different in ADR group in comparison to SC therapy group.

CONCLUSIONS

ADR induced progressive duration dependant cerebral degenerative changes. These changes were ameliorated following cord blood human mesenchymal stem cell therapy. A reciprocal relation was recorded between the extent of regeneration and the existence of undifferentiated mesenchymal stem cells.

[Aspects of encephalopathy in oncologic patients after chemotherapy]

OBJECTIVE

To study clinical presentations and neuroimaging results in post chemotherapy encephalopathy.

MATERIAL AND METHODS

We examined 27 patients with cancer after chemotherapy (n=16) or chemoradiation (n=11).

RESULTS AND CONCLUSION

All patients complained of memory impairment, sluggish mentality, moderate headache, fatigue, sleep disorder, irritability. Their neurologic status included different organic symptoms. Post chemotherapy encephalopathy is characterized by the combination of severe cerebral asthenia and different organic neurologic symptoms with moderate cephalgic syndrome. MRT showed single and multiple loci of gliosis in the white matter.

Challenges in research on the neural basis of „chemobrain”

Cancer survivors treated with chemotherapy frequently complain about impairment of cognitive functions including attention and memory. While the contribution of factors like psychological distress, anxiety or fatigue to this “chemobrain” syndrome has been discussed, studies in rodents have demonstrated the toxicity of various chemotherapeutic substances to the adult central nervous system. In humans, structural brain imaging has revealed both reduced gray and white matter volume and decreased white matter integrity related to chemotherapeutic treatment. Studies of brain function have found alterations in brain activation patterns during different types of tasks. Nevertheless, further clinical research using prospective designs in larger samples is required to better understand the relationship between chemotherapy and cognitive deficits. Variables that need to be considered more systematically include drug dose, genetic variations, and psychological factors. Assessing both electroencephalographic and hemodynamic responses during tasks at different stages of the processing hierarchy and at different difficulty levels should help in pinpointing the cortical processes affected by chemotherapy.

A pilot study: application of hemoglobin and cortisol levels, and a memory test to evaluate the quality of life of breast cancer patients on chemotherapy

BACKGROUND

Short-term memory (STM) decline in breast cancer patients resulting from chemotherapy was evaluated by means of blood biomarkers, a questionnaire, and a computerized STM test.

METHODS

This study was conducted from January 2013 to June 2013, recruiting 90 subjects: 30 breast cancer patients beginning the 3rd of 4th cycles of docetaxel and cyclophosphamide chemotherapy, 30 recovered patients (who completed 4 cycles of docetaxel for a minimum of 6 months), and 30 healthy subjects (disease-free females). The levels of hemoglobin, red and white blood cells, and cortisol in serum, and a computerized STM test were analyzed to estimate the effects of chemotherapy on STM. A questionnaire was given to all subjects to assess quality of life.

RESULTS

Statistically significant differences were observed for the blood parameters (hemoglobin, red and white blood cells, and cortisol levels) between healthy and on-treatment subjects (respectively 13.47 ± 0.96 g/dL vs 5.37 ± 0.38 g/dL, 4.58 ± 0.41 10(12)/L vs 2.07 ± 0.13 10(12)/L, and 6.15 ± 1.03 10(9)/L vs 0.86 ± 0.41 10(9)/L). Scores of the STM test were significantly lower for patients compared to healthy subjects. As indicated by the results of the questionnaire, breast cancer patients had a higher tendency to forget than healthy controls (X(2)=3.15; p<0.0001) and recovered subjects (X(2)=3.15; p<0.0001).

CONCLUSION

We found depleted levels of hemoglobin, red and white blood cells as a result of chemotherapy, and elevated levels of stress correlated with poor performances in the computerized STM test. A higher cortisol level might be an important precursor of STM deterioration. Monitoring cortisol would be beneficial for evaluating the quality of life of breast cancer patients on chemotherapy.