Is 'chemo-fog'/'chemo-brain' caused by cancer chemotherapy?

A likely association between low mannan-binding lectin level and brain fog onset in long COVID patients

Brain fog can be described as a constellation of new-onset neuropsychiatric sequelae in the post-acute phase of COVID-19 (long COVID). The symptoms include inattention, short-term memory loss, and reduced mental acuity, which may undermine cognition, concentration, and sleep. This cognitive impairment, persisting for weeks or months after the acute phase of SARS-CoV-2 infection, can significantly impact on daily activities and the quality of life. An important role for the complement system (C) in the pathogenesis of COVID-19 has emerged since the beginning of pandemic outbreak. A number of pathophysiological characteristics including microangiopathy and myocarditis have been attributed to dysregulated C activation due to SARS-CoV-2 infection. Mannan-binding lectin (MBL), the first recognition subcomponent of the C lectin pathway, has been shown to bind to glycosylated SARS-CoV-2 spike protein, genetic variants of MBL2 are suggested to have an association with severe COVID-19 manifestations requiring hospitalization. In the present study, we evaluated MBL activity (lectin pathway activation) and levels in the sera of a cohort of COVID-19 patients, presenting brain fog or only hyposmia/hypogeusia as persistent symptoms, and compared them with healthy volunteers. We found significantly lower levels of MBL and lectin pathway activity in the sera of patients experiencing brain fog as compared to recovered COVID-19 patients without brain fog. Our data indicate that long COVID-associated brain fog can be listed among the variegate manifestations of increased susceptibility to infections and diseases contributed by MBL deficiency.

Neurological post-acute sequelae of SARS-CoV-2 infection

The novel coronavirus disease 19 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), can have two phases: acute (generally 4 weeks after onset) and chronic (>4 weeks after onset). Both phases include a wide variety of signs and symptoms including neurological and psychiatric symptoms. The signs and symptoms that are considered sequelae of COVID-19 are termed post-COVID condition, long COVID-19, and post-acute sequelae of SARS-CoV-2 infection (PASC). PASC symptoms include fatigue, dyspnea, palpitation, dysosmia, subfever, hypertension, alopecia, sleep problems, loss of concentration, amnesia, numbness, pain, gastrointestinal symptoms, depression, and anxiety. Because the specific pathophysiology of PASC has not yet been clarified, there are no definite criteria of the condition, hence the World Health Organization's definition is quite broad. Consequently, it is difficult to correctly diagnose PASC. Approximately 50% of patients may show at least one PASC symptom up to 12 months after COVID-19 infection; however, the exact prevalence of PASC has not been determined. Despite extensive research in progress worldwide, there are currently no clear diagnostic methodologies or treatments for PASC. In this review, we discuss the currently available information on PASC and highlight the neurological sequelae of COVID-19 infection. Furthermore, we provide clinical suggestions for diagnosing and caring for patients with PASC based on our outpatient clinic experience.

Accelerated aging of the brain transcriptome by the common chemotherapeutic doxorubicin

Cancer is one of the most common age-related diseases, and over one-third of cancer patients will receive chemotherapy. One frequently reported side effect of chemotherapeutic agents like doxorubicin (Doxo) is impaired cognitive function, commonly known as "chemotherapy-induced cognitive impairment (CICI)", which may mimic accelerated brain aging. The biological mechanisms underlying the adverse effects of Doxo on the brain are unclear but could involve mitochondrial dysfunction. Here, we characterized brain (hippocampal) transcriptome and cognitive/behavioral changes in young mice treated with Doxo +/- the mitochondrial therapeutic MitoQ. We found that Doxo altered transcriptome/biological processes related to synaptic transmission and neurotransmitter function, neuronal health and behavior, and that these gene expression changes were: 1) similar to key differences observed in transcriptome data on brain aging; and 2) associated with related, aging-like behavioral differences, such as decreased exploration time and impaired novel object recognition test (NOR, an index of learning/memory) performance. Interestingly, MitoQ partially prevented Doxo-induced transcriptome changes in the brain, but it had no effect on behavior or cognitive function. Collectively, our findings are consistent with the idea that chemotherapeutic agents could induce neuronal/gene expression and behavioral changes similar to those that occur during brain aging. In this context, mitochondrial therapeutics may have potential as treatments for CICI at the biological level, but their effects on behavior/cognitive function require further investigation.

Amelioration of Tumor Targeting and In Vivo Biodistribution of 99mTc-Methotrexate-Gold Nanoparticles (99mTc-Mex-AuNPs)

Gold nanoparticles (AuNPs) represent very attractive and promising drug delivery carriers due to their unique dimensions, adjustable surface functions, and controllable drug release. Therefore, AuNPs are used to overcome the limitations of conventional chemotherapy, for example methotrexate (Mex), one of the first-generation chemotherapy drugs for cancer treatment, whose usefulness has been restricted due to drug resistance and dose-dependent side effects. In the present study, the AuNPs drug delivery system was synthesized and loaded with technetium-99 m radiolabeled Methotrexate (^99mTc-Mex) to produce new potential nanoradiopharmaceutical for tumor targeting and further imaging. The Methotrexate loaded gold nanoparticles (Mex-AuNPs) successfully prepared in small spherical particle size (20.3 nm), polydispersity index PDI (< 0.5) and a zeta potential (-17.6 mV) with loading efficiency% (93 ± 1.2%) of methotrexate at 30 min as an optimum stirring time and showed strong absorption peak for Mex-AuNPs at λ_max, 525 nm. The in vitro release profile of Mex-AuNPs showed high release percent of methotrexate at pH 5; the Q_0.5 h and Q_8h were 21.2 ± 1.5% and 92.9 ± 3.4%, respectively. The in vitro cytotoxicity was investigated at different concentrations (0.024-50 μl/100 μl) of Mex-AuNPs (1 mg/ml) against MCF-7 (Michigan Cancer Foundation-7) breast cancer cells by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) assay technique. Mex-AuNPs showed higher anticancer activity with low inhibitory concentration (IC₅₀ = 0.098 μl/100 μl) that was three times lower than the inhibitory concentration (IC₅₀) of methotrexate (IC₅₀ = 0.3 μl/100 μl). ^99mTc-Mex complex prepared by direct reduction method at maximum radiochemical yield (RCY)% ̴ 98.3 ± 1.09 % was loaded in AuNPs to form ^99mTc-Mex-AuNPs with loading efficiency% (93 ± 1.2 %) at 30 min of stirring time. ^99mTc-Mex-AuNPs showed convenient in vitro stability in mice serum up to 24 h with RCY% > 90 %. The preclinical biodistribution studies of ^99mTc-Mex-AuNPs were performed in 3 experimental groups A (intravenous (I.V.) injected normal mice), B and C (I.V. and intratumor (I.T.) injected tumor bearing mice, respectively). The ^99mTc-Mex-AuNPs achieved highest tumor uptake (93 ± 0.39 %ID/g) and highest Target/NonTarget (T/NT) ratio (58.1 ± 0.91) with high Tumor/Blood (T/B) ratio (25.8 ± 0.11) at 10 min post I.T. injection and retained high tumor uptake (79 ± 0.65 %ID/g) up to 60 min post I.T. injection before escaping into blood stream. Consequently, ^99mTc-Mex-AuNPs can be considered as new potential nanoradiopharmaceutical in tumor diagnosis.

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.

Doxorubicin chemotherapy-induced "chemo-brain": Meta-analysis

Doxorubicin is a leading chemotherapeutic halting cellular replication and inducing p53-dependent apoptosis in cancerous tissue. Like many chemotherapies, doxorubicin damages healthy tissue throughout the body through cellular mechanisms independent of its chemotherapeutic action. Although cognitive impairment is commonly recorded in patients after chemotherapy, the occurrence of doxorubicin-induced "chemo-brain" is debated, as doxorubicin cannot cross the blood-brain barrier. However, the potential of indirect doxorubicin neurotoxicity remains, providing a foundation for doxorubicin-mediated chemo-brain. We present the first meta-analysis of defined cognitive performance of doxorubicin-treated patients. A search of PubMed and MedLine collected 494 studies, 14 of which met analysis criteria. Performance of 511 doxorubicin-treated women with breast cancer was compared to that of 306 healthy controls across measures of defined cognitive modalities. Treated patients experience significant impairment in global cognition compared to controls (g₌ -0.41, P < 0.001), with select impairment in executive function (g = -0.25, P < 0.0001), language (g = -0.30, P < 0.0001), memory (g = -0.12, P < 0.01) and processing speed (g = -0.28, P < 0.01). Within memory, short-term verbal memory is most significantly affected (g = -0.21, P < 0.01). Impairment in select cognitive modalities (executive function, language, memory, short-term verbal memory, processing speed) is prevalent in doxorubicin-treated patients, with some cognitive functions remaining intact (attention, motor function, visuospatial abilities). This information can guide the development of future interventions to improve quality-of-life (QOL) and doxorubicin-derived therapies that target cytotoxicity to cancerous tissue, avoiding healthy tissue damage, which is mediated by seemingly independent mechanisms.

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.

Electrochemical Measurement of Dopamine Release and Uptake in Zebrafish Following Treatment with Carboplatin

Post-chemotherapy cognitive impairment, also known as 'chemobrain,' is a neurological condition in which cognitive function is impaired as a result of cancer chemotherapy treatment. In this work, we used fast-scan cyclic voltammetry (FSCV) to measure electrically evoked dopamine release and uptake in whole brain preparations from zebrafish that have been treated with carboplatin, an agent associated with chemobrain. We administered carboplatin by addition to the fish's tank water or their food. One week of treatment with 100 μM carboplatin in the water was needed to significantly impair dopamine release (∼40 % of control); however, only one day of treatment through the zebrafish's food was needed to cause a similar impairment. Atomic absorption spectroscopy measurements suggested that administration through food resulted in higher initial levels of carboplatin compared to water administration, but water administration resulted in an increase over time. Uptake, determined by modeling stimulated release plots, was unaffected. These results are consistent with our previous findings of diminished neurotransmitter release in rats and support a role for zebrafish in chemobrain-related studies.

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.

Sexuality and elderly with chronic diseases: A review of the existing literature

Background:

Increased life expectancy and the growing phenomenon of aging can lead to increased burden of chronic diseases (CDs) which adversely affects the overall health of elderly, their sexuality in particular. Sexual life of an aged population is overlooked in many of the societies. In the present narrative review, we aim to assess the impact of CDs on sexual function of elderly people.

Materials and Methods:

We used internet databases including PubMed, EMBASE, ISI Web of Science, Google Scholar, SID, Iran Medex, Magiran, IPPF, and UNFPA without time limit. Ninety-eight out of 174 relevant articles were selected which met the inclusion criteria: those articles were research-based in English or Persian (original or review articles) and textbooks; specified one or more CDs and sexual function of the cases; elderly people over the age of sixty, men and women; and coordination between articles and research goals. We excluded qualitative and case studies. We reported the most related CDs with sexual function in literature review and used the biological and psychological impact of the CDs on sexual function of elderly population based on the conceptual model of Verschuren et al. (2010).

Results:

The results of the studies were classified into the themes including physical, psychological, and cultural and social. Diabetes, cardiovascular, cancerous, and chronic respiratory diseases and also some medications can reduce sexual capacity and desire in particular resulting in negative impact on the quality of elderly sexual life. CDs may influence sexual expressions and responses which adversely affect one's mood and energy so that can cause depression and grief, as well as loss of self-confidence, self-esteem, and self-concept in elderly adults. The factors affecting sexuality of an elderly with CDs include cultural and mythical beliefs about age and illnesses, fear, and embarrass of changed physical appearance. The research conducted among elderly population examining the adverse influence of CDs on aged people's sexual life in general, sexual function and performance, and intimate interaction.

Conclusion:

It is considered that programs on sexual health needs of aged population for the health-care workers can prove beneficial in improving sexual health.

Assessing cognitive function in adults during or following chemotherapy: a scoping review

PURPOSE

The purpose of this scoping review was to determine the feasibility of conducting a systematic review of approaches for screening or assessing cognitive function that were comprehensive and that could be incorporated into clinical settings.

METHODS

Using the scoping review approach developed by Arksey and O'Malley, we searched Ovid Embase 1980-, Ovid PsycINFO 1806-, Ovid Health and Psychosocial Instruments 1985-, EBSCOhost CINAHL, ISI Web of Science (Science Citation Index 1900-), Social Sciences Citation Index 1900-, Conference Proceedings Citation Index -Science 1990-, Conference Proceedings Citation Index -Social Science & Humanities 1990-, Scopus 1960-, with no language restrictions. Searches were conducted in April 2009 and updated in February 2013. Studies of adults treated with chemotherapy that included at least seven of the eight domains of cognition were included.

RESULTS

Eleven studies met inclusion criteria. No screening tools suitable for inclusion in a clinic were identified. The studies reviewed varied by inclusion/exclusion criteria, design, and instruments for assessing cognitive function, and thus, there are not yet enough studies to warrant a systematic review on this topic.

Scale-free brain dynamics under physical and psychological distress: pre-treatment effects in women diagnosed with breast cancer

Stressful life events are related to negative outcomes, including physical and psychological manifestations of distress, and behavioral deficits. Patients diagnosed with breast cancer report impaired attention and working memory prior to adjuvant therapy, which may be induced by distress. In this article, we examine whether brain dynamics show systematic changes due to the distress associated with cancer diagnosis. We hypothesized that impaired working memory is associated with suppression of "long-memory" neuronal dynamics; we tested this by measuring scale-free ("fractal") brain dynamics, quantified by the Hurst exponent (H). Fractal scaling refers to signals that do not occur at a specific time-scale, possessing a spectral power curve P(f)∝ f(-β); they are "long-memory" processes, with significant autocorrelations. In a BOLD functional magnetic resonance imaging study, we scanned three groups during a working memory task: women scheduled to receive chemotherapy or radiotherapy and aged-matched controls. Surprisingly, patients' BOLD signal exhibited greater H with increasing intensity of anticipated treatment. However, an analysis of H and functional connectivity against self-reported measures of psychological distress (Worry, Anxiety, Depression) and physical distress (Fatigue, Sleep problems) revealed significant interactions. The modulation of (Worry, Anxiety) versus (Fatigue, Sleep Problems, Depression) showed the strongest effect, where higher worry and lower fatigue was related to reduced H in regions involved in visuospatial search, attention, and memory processing. This is also linked to decreased functional connectivity in these brain regions. Our results indicate that the distress associated with cancer diagnosis alters BOLD scaling, and H is a sensitive measure of the interaction between psychological versus physical distress.

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

BACKGROUND

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

AIM

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

METHOD

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

FINDINGS

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

DISCUSSION

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

CONCLUSION

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

Women's experiences of cognitive changes or 'chemobrain' following treatment for breast cancer: a role for occupational therapy?

BACKGROUND/AIM

Changes to functioning and cognition are commonly reported following chemotherapy. These changes are highly individual, and may not be fully recognised or understood. Breast cancer is the most common cancer diagnosed in women worldwide, yet little is known about the impact of cognitive changes for these women following treatment and many do not benefit from occupational therapy services. The aim was to describe changes in cognitive function experienced by women who had undergone chemotherapy, and the strategies used to overcome the associated challenges.

METHOD

This was a qualitative phenomenological study conducted with nine women, aged between 39 and 67 years, from New South Wales. Participants were breast cancer survivors who had received chemotherapy treatment, and self-reported chemobrain symptoms. Data were collected through semi-structured in-depth telephone and face-to-face interviews. Data were transcribed, coded and thematically analysed.

RESULTS

Six themes described the chemobrain experience for these women. They were: uncertainty about the origin of the chemobrain experience; persistent but inconsistent impacts on function; simple function turned complex; losing functional independence in family life; strategies to maintain function; and the need for recognition of the subjective experience of cancer treatment.

CONCLUSION

The experiences of cognitive and functional changes following chemotherapy for those reporting chemobrain symptoms are highly individual, and include the need for adaptive strategies. Some similarities in the types of impairments were experienced. As breast cancer survivorship rates continue to rise, there is a need for occupational therapy services to assist women in returning to daily occupations during or following their cancer treatment.

Cancer 'survivor-care': II. Disruption of prefrontal brain activation top-down control of working memory capacity as possible mechanism for chemo-fog/brain (chemotherapy-associated cognitive impairment)

WHAT IS KNOWN AND OBJECTIVE

Cancer chemotherapy-associated cognitive impairments (termed 'chemo-fog' or 'chemo-brain'), particularly in memory, have been self-reported or identified in cancer survivors previously treated with chemotherapy. Although a variety of deficits have been detected, a consistent theme is a detriment in visuospatial working memory. The parietal cortex, a major site of storage of such memory, is implicated in chemotherapy-induced damage. However, if the findings of two recent publications are combined, the (pre)frontal cortex might be an equally viable target. Two recent studies, one postulating a mechanism for 'top-down control' of working memory capacity and another visualizing chemotherapy-induced alterations in brain activation during working memory processing, are reviewed and integrated.

COMMENT

A computational model and the proposal that the prefrontal cortex plays a role in working memory via top-down control of parietal working memory capacity is consistent with a recent demonstration of decreased frontal hyperactivation following chemotherapy.

WHAT IS NEW AND CONCLUSION

Chemotherapy-associated impairment of visuospatial working memory might include the (pre)frontal cortex in addition to the parietal cortex. This provides new opportunity for basic science and clinical investigation.

Apolipoprotein A-I: insights from redox proteomics for its role in neurodegeneration

Proteomics has a wide range of applications, including determination of differences in the proteome in terms of expression and post-translational protein modifications. Redox proteomics allows the identification of specific targets of protein oxidation in a biological sample. Using proteomic techniques, apolipoprotein A-I (ApoA-I) has been found at decreased levels in subjects with a variety of neurodegenerative disorders including in the serum and cerebrospinal fluid (CSF) of Alzheimer disease (AD), Parkinson disease (PD), and Down syndrome (DS) with gout subjects. ApoA-I plays roles in cholesterol transport and regulation of inflammation. Redox proteomics further showed ApoA-I to be highly oxidatively modified and particularly susceptible to modification by 4-hydroxy-2-trans-nonenal (HNE), a lipid peroxidation product. In the current review, we discuss the consequences of oxidation of ApoA-I in terms of neurodegeneration. ROS-associated chemotherapy related ApoA-I oxidation leads to elevation of peripheral levels of tumor necrosis factor-α (TNF-α) that can cross the blood-brain barrier (BBB) causing a signaling cascade that can contribute to neuronal death, likely a contributor to what patients refer to as "chemobrain." Current evidence suggests ApoA-I to be a promising diagnostic marker as well as a potential target for therapeutic strategies in these neurodegenerative disorders.

Assessing the relationship between physical fitness activities, cognitive health, and quality of life among older cancer survivors

Chemotherapy-related cognitive impairment, known as "chemobrain," has been described as a side effect of chemotherapy and is associated with cognitive changes on quality of life especially among older cancer survivors. This longitudinal feasibility study examined the relationship between physical fitness, cognitive health, and quality of life among two groups of older adults: those on chemotherapy, and those who have completed chemotherapy. To assess cognitive health, we used the Montreal Cognitive Assessment and demographic information from the Healthy Brain Questionnaire. For quality of life, we used the McGill Quality of Life assessment. Physical activity was assessed using Metabolic Equivalency Tasks from the Compendium of Physical Activities classification system. t-Tests and regression analyses indicated that at Time 1 those on chemotherapy had lower cognitive health scores than those off chemotherapy. Yet at Time 2, as physical activities increased, cognitive health and quality of life improved for those on chemotherapy. However, those who had completed chemotherapy also benefited from an increase in physical activities over time. The results have implications for health care practitioners in oncology settings to better inform patients of cognitive challenges resulting from chemotherapy and the importance of participation in physical activities. Future research should compare different age groups among a larger sample.

Experiences of Changes in Cognitive Function for Women treated with Chemotherapy for Breast Cancer

PURPOSE

The purpose of this study was to describe the experiences of the process of the change in cognitive function for women treated with chemotherapy for breast cancer.

METHODS

There were ten participants in total in this study. Data were gathered utilizing in-depth interviews over 3 times from September 2010 to January 2011. Data were analyzed by employing Strauss and Corbin's (1998) grounded theory methodology.

RESULTS

Findings indicate that causal conditions of these results were 'side effects of chemotherapy' and 'menopausal state', including contextual conditions as, 'mental fatigue' and 'anxiety about recurrence'. The core category was identified as 'confronting with unexpected chaos'. Intervening conditions were 'support from other people', 'lack of information on cognitive impairment'. Interaction strategies were 'changing the habit of life', 'making efforts for living life' and 'seeking for medical information'. Consequences of the process were 'physical restriction', 'difficulty in social life', 'disturbed working ability' and 'psychological distress'.

CONCLUSION

The results of this study show that nurses should recognize there is a notable difference between individual patient's contextual conditions and interactive strategies. Furthermore educational information and individualized intervention should be provided to improve cognitive function for women with breast cancer.

Effects of repeated administration of chemotherapeutic agents tamoxifen, methotrexate, and 5-fluorouracil on the acquisition and retention of a learned response in mice

RATIONALE

A number of cancer chemotherapeutic agents have been associated with a loss of memory in breast cancer patients although little is known of the causality of this effect.

OBJECTIVES

To assess the potential cognitive effects of repeated exposure to chemotherapeutic agents, we administered the selective estrogen receptor modulator tamoxifen or the antimetabolite chemotherapy, methotrexate, and 5-fluorouracil, alone and in combination to mice and tested them in a learning and memory assay.

METHODS

Swiss-Webster male mice were injected with saline, 32 mg/kg tamoxifen, 3.2 or 32 mg/kg methotrexate, 75 mg/kg 5-fluorouracil, 3.2 or 32 mg/kg methotrexate in combination with 75 mg/kg 5-fluorouracil once per week for 3 weeks. On days 23 and 24, mice were tested for acquisition and retention of a nose-poke response in a learning procedure called autoshaping. In addition, the acute effects of tamoxifen were assessed in additional mice in a similar procedure.

RESULTS

The chemotherapeutic agents alone and in combination reduced body weight relative to saline treatment over the course of 4 weeks. Repeated treatment with tamoxifen produced both acquisition and retention effects relative to the saline-treated group although acute tamoxifen was without effect except at a behaviorally toxic dose. Repeated treatment with methotrexate in combination with 5-fluorouracil produced effects on retention, but the magnitude of these changes depended on the methotrexate dose.

CONCLUSIONS

These data demonstrate that repeated administration of tamoxifen or certain combination of methotrexate and 5-fluorouracil may produce deficits in the acquisition or retention of learned responses which suggest potential strategies for prevention or remediation might be considered in vulnerable patient populations.

A proposed mechanism for chemotherapy-related cognitive impairment ('chemo-fog')

WHAT IS KNOWN AND OBJECTIVE

Chemotherapeutic drugs for cancer treatment are, of necessity, cytotoxic. Unintended damage to normal central nervous system neuronal structure or function might lead to deleterious adverse effects on cognitive function, a mild form of which is reported by some cancer survivors. Understanding the physiologic connection between cancer chemotherapy and the reported cognitive dysfunction, could help inform choice of drugs, treatment regimens and new drug development. Our objective is to comment on a proposed mechanism for 'chemo-fog'.

COMMENT

An increasing number of patients are surviving cancer and are generating a new and rapidly growing category within the healthcare system. Some of these cancer survivors are reporting that they are experiencing residual and lingering effects from the cancer, or from its treatment, and that they now need care as survivors. This has given rise to the new field of 'survivor care'. Control of chemo-fog is an important aspect and understanding its mechanism, the basis for more rationale therapy. Such insight would also help direct drug-discovery efforts.

WHAT IS NEW AND CONCLUSION

New evidence suggests that 'chemo-fog' may be due to excessive cytokine release by the cytotoxic agents. Control of the elevated levels of the blood-brain-barrier-permeable pro-inflammatory cytokines, may help minimize this adverse effect.

Disruption of learning processes by chemotherapeutic agents in childhood survivors of acute lymphoblastic leukemia and preclinical models

OBJECTIVE

With the survival rate of acute lymphoblastic leukemia (ALL) surpassing 90 percent within this decade, new research is emerging in the field of late effects. A review of the research investigating the relationship of treatment regimens for ALL to specific late effect deficits, underlying mechanisms, and possible remediation is warranted to support continued studies.

METHODS

The clinical literature was briefly surveyed to describe the occurrence and topography of late effects, specifically neurocognitive deficits. Additionally, the preclinical literature was reviewed to uncover potential underlying mechanisms of these deficits. The advantages of using rodent models to answer these questions are outlined, as is an assessment of the limited number of rodent models of childhood cancer treatment.

RESULTS

The literature supports that childhood survivors of ALL exhibit academic difficulties and are more likely to be placed in a special education program. Behavioral evidence has highlighted impairments in the areas of attention, working memory, and processing speed, leading to a decrease in full scale IQ. Neurophysiological and preclinical evidence for these deficits has implicated white matter abnormalities and acquired brain damage resulting from specific chemotherapeutic agents commonly used during treatment.

CONCLUSIONS

The exact role of chemotherapeutic agents in learning deficits remains mostly unknown. Recommendations for an improved rodent model of learning deficits in childhood cancer survivors are proposed, along with suggestions for future directions in this area of research, in hopes that forthcoming treatment regimens will reduce or eliminate these types of impairments.

Cancer 'survivor-care': I. the α7 nAChR as potential target for chemotherapy-related cognitive impairment

WHAT IS KNOWN AND OBJECTIVE

Far more patients are now surviving cancer than ever before because of major advances in the diagnosis and treatment of primary and metastatic malignancy. Adjuvant chemotherapeutic drug and combination regimens have contributed to the success. However, persistent residual adverse effects involving mild impairment of cognitive impairment have been reported. Our objective is to review and to comment on the basic science and clinical evidence of potential pharmacologic targets for managing this emerging concern.

COMMENT

A search was conducted of basic science and clinical literature related to the objective and the information obtained was organized and evaluated from the perspective of its insight into potential pharmacotherapeutic targets. A large body of evidence suggests that the nicotinic acetylcholine receptor (nAChR), and in particular the α7 subtype, is involved in memory and that agonists and positive allosteric modulators of this receptor have potential in schizophrenia and Alzheimer animal models and patients.

WHAT IS NEW AND CONCLUSION

We identify significant indirect evidence that the selective α7 nAChR drugs that are currently being investigated for cognitive improvement in schizophrenia and Alzheimer disease patients may be useful in cancer chemotherapy-related cognitive impairment. The clinical use of those drugs should be explored.

Effects on the visual system might contribute to some of the cognitive deficits of cancer chemotherapy-induced 'chemo-fog'

The diminution in certain aspects of cognitive function that is reported to occur in some patients during or after adjuvant cancer chemotherapy is variously known as 'chemo-fog', 'chemo-brain' or other such term. In addition to reported deficits in attention, concentration and other functions, most, if not all, of the studies report deficits involving visual-spatial function or visual memory. Since the visual system is part of the nervous system, it seems reasonable to ask if it is susceptible to some of the deleterious effects produced by adjuvant chemotherapeutic drugs. We propose here the possibility that some portion of the vision-related aspects of the 'chemo-fog' spectrum of cognitive deficits results from a direct action of the adjuvant drugs on the visual system or from drug/drug or site/site interaction between effects on the visual system and other critical brain regions.

Confronting chemobrain: an in-depth look at survivors' reports of impact on work, social networks, and health care response

Introduction

Mild cognitive impairment following chemotherapy is one of the most commonly reported post treatment symptoms by breast cancer survivors. This deterioration in cognitive function, commonly referred to as “chemobrain” or “chemofog,” was largely unacknowledged by the medical community until recent years. Although chemobrain has now become the subject of more vigorous exploration, little is known about this specific phenomenon’s psychosocial impact on breast cancer survivors. This research documents in-depth the effects that cognitive impairment has on women’s personal and professional lives, and our data suggest that greater attention needs to be focused on this arena of survivorship.

Methods

The results are based on an in-depth qualitative study of 74 white and African American breast cancer survivors in California who experience post-treatment side effects. The data reported herein were obtained through the use of focus groups and in-depth interviews.

Results

Our data indicate that cognitive impairment can be problematic for survivors, with many asserting that it is their most troublesome post treatment symptom. Survivors report diminished quality of life and daily functioning as a result of chemobrain. Respondents detail a range of coping strategies that they are forced to employ in order to manage their social and professional lives.

Discussions/conclusions

Chemobrain significantly impairs a proportion of cancer survivors, at great cost to them economically, emotionally, and interpersonally. This suggests that more research needs to be conducted on the psychosocial ramifications of post treatment symptoms in order to inform the efforts of the medical and mental health communities as well as the support networks of survivors.

Implications for cancer survivors

A better and broader understanding of the effects of cognitive impairment both in the medical community and among lay people could pave the way for improved social and psychological services for this population.

Sexual issues in special populations: geriatric oncology - sexuality and older adults

OBJECTIVE

To provide an overview of sexuality and sexual expression in older adult cancer survivors and to outline implications for nursing and interdisciplinary practice.

DATA SOURCES

Research articles, abstracts, reviews, and clinical expertise.

CONCLUSION

Unique features of sexuality in late life provide evidence to support clinical exploration of sexuality for older adult cancer survivors. Approaches to intervention with older adult cancer survivors are predicated on adaptation of best practices in sexuality and sexual health to create care that is sensitive to age and generation. Targeted research in sexuality for older adult cancer survivors includes intimacy, relationship, sexual experience, and imbedded sexual behavior.

IMPLICATIONS FOR NURSING PRACTICE

Nurses can improve the care of older adults with cancer by careful consideration of intimacy and sexuality using standards of practice with younger adults integrated with understanding of issues unique to later life.

Cognitive function after chemotherapy in adults with solid tumours

BACKGROUND

Evidence is emerging that some cancer survivors suffer cognitive impairment after chemotherapy; the cause is unknown.

METHODS

Here we review studies evaluating cognitive impairment in adult cancer survivors and discuss methodological challenges associated with this research. We evaluate evidence for cognitive impairment in cancer patients, the incidence of self-reported impairment, and identify potential mechanisms and confounders.

RESULTS

Most studies of cognitive function are cross-sectional and report impairment in 15-45% of subjects. Longitudinal studies suggest that some impairment is present prior to receiving chemotherapy, and that this worsens in some patients. The aetiology is unknown. A larger number of subjects self-report changes in cognitive function after chemotherapy; this does not correlate with objective testing.

CONCLUSIONS

Cognitive impairment occurs in a subset of cancer survivors and is generally subtle. Most evidence suggests an association with chemotherapy although other factors associated with the diagnosis and treatment of cancer may contribute.

A meta-analysis of the sensitivity of various neuropsychological tests used to detect chemotherapy-induced cognitive impairment in patients with breast cancer

PURPOSE/OBJECTIVES

To identify which neuropsychological tests have been used to evaluate chemotherapy-induced impairment in various domains of cognitive function in patients with breast cancer and to determine the sensitivity of each of the tests through estimation of effect size.

DATA SOURCES

Original studies published from 1966-June 2006.

DATA SYNTHESIS

Although an array of neuropsychological tests are available to measure the various domains of cognitive function, information is lacking regarding the sensitivity and specificity of the tests to detect changes in cognitive function from chemotherapy.

CONCLUSIONS

This meta-analysis provides initial data on the sensitivity of some neuropsychological tests to determine chemotherapy-induced changes in cognitive function in patients with breast cancer.

IMPLICATIONS FOR NURSING

The identification of sensitive neuro-psychological tests is crucial to further understanding of chemotherapy-induced cognitive impairments.

Chemo brain - a psychotropic drug phenomenon?

The phenomenon of 'chemo brain' refers to a cluster of potentially long-lasting, cognitive deficiencies which are caused by systemic cancer treatments. While the oncology community has gradually acknowledged the existence of chemo brain as an unintended consequence of anti-neoplastic therapies, other fields of medicine have been less astute. Preliminary research evidence has suggested a role for many existing psychopharmaceuticals in fighting malignancies, based upon the capacity of these drugs to modify gene expression, cell turnover, and cell death (e.g., apoptosis). The author presents the hypothesis that the same mechanisms which suppress the growth and survival of cancer cells may pose similar hazards to non-diseased neurons, thereby inducing the cognitive changes which oncologists have come to associate with chemo brain. The article discusses the specific examples of valproic acid, clomipramine, and fluoxetine as treatments for solid tumors, primary brain tumors, and Burkitt's lymphoma, respectively. Clinicians, regardless of specialization, are encouraged to consider the potential reality of psychotropic chemo brain, in order to avoid or limit the use of medications which cause it, and in order to prioritize the delivery of rehabilitative strategies in an effort to mitigate or reverse its features.

Recent Publications on Medications and Pharmacy

Hospital Pharmacy presents this new feature to keep pharmacists abreast of new publications in the medical/pharmacy literature. Articles of interest will be abstracted monthly regarding a broad scope of topics.