Intraindividual variability in reaction time before and after neoadjuvant chemotherapy in women diagnosed with breast cancer

Neuropsychological assessment, intervention, and best practices for women with non-Central nervous system cancer: A scoping review of current standards

Objective: Existing literature has sought to characterize the broad cognitive impact of non-central nervous system cancer and its treatment, including chemotherapy, radiation, surgery, and hormonal regulation. However, despite the frequency of women that are diagnosed with breast and gynecological cancer, there is limited research on the specific cognitive experiences of women undergoing cancer treatment. Presently, the current literature lacks concise guidance for neuropsychologists to support the cognitive health of women facing cancer, despite the acknowledged impact of cancer interventions and chronic illness on cognitive outcomes. Method: Applying scoping review criteria outlined by Peters et al. (2015) and adhering to Preferred Reporting Items for Systemic Reviews and Meta-Analysis (PRISMA) guidelines, we conducted a comprehensive examination of literature spanning multiple databases (Google Scholar, PubMed, PsychINFO) with a focus on the cognitive impact of cancer treatment on women. Conclusions: Women are subject to unique treatment-related outcomes due to the impact of hormonal alterations, differences in metabolization of certain chemotherapies, and psychosocial risk factors. Despite the known impact of cancer intervention, chronic illness, and cancer-related sequelae on cognitive outcomes, the current literature does not parsimoniously outline best practices for neuropsychologists to promote the health of women experiencing cancer. The current paper (1) provides an overview of the cognitive implications of cancer treatment with an intentional focus on cancers that are more prevalent in women versus men, (2) addresses the characteristics of this impact for women undergoing cancer intervention(s), and (3) provides possible intervention and treatment strategies for mental health providers and neuropsychologists.

Chemotherapy-induced cognitive impairment in breast cancer survivors: A systematic review of studies from 2000 to 2021

BACKGROUND

Studies have indicated that apart from enhancing patient survival, chemotherapy has adverse side effects on the psychological, social, and cognitive functions of breast cancer survivors.

AIMS

This study was conducted to understand chemotherapy's impact on breast cancer survivors' cognitive functions.

METHODS AND RESULTS

Our study is a systematic review based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. We searched English databases, including PubMed/MEDLINE, PsycINFO, and Web of Science, and Persian databases, such as Irandoc and Elmnet, using Persian keywords of cancer, breast cancer, chemotherapy, cognitive functions, executive functions, and neuropsychological functions. Two reviewers independently evaluated the full text of the articles according to predefined criteria. Among the 937 available studies, 26 were selected based on the inclusion and exclusion criteria, of which 17 (65%) were longitudinal and 9 (35%) were cross-sectional. The findings indicated a significant relationship between the use of chemotherapy and cognitive impairments, most notably attention, working and short-term memory, and executive functions. However, the studies differed in their findings regarding the long-term persistence of cancer-related cognitive impairment (CRCI), which could be due to the wide range of tools used, different methods to measure cognitive functions, and the difference in the sample size of the studies.

CONCLUSION

Chemotherapy, affecting cortical and subcortical brain structures, causes a set of cognitive impairments that can lead to impairments in social responsibility acceptance, daily functioning, and quality of life of women. Therefore, rigorous and extensive research design is required to understand the causes and consequences of CRCI using standardized and sensitive measures of cognitive functions. Specifically, studies comparing the effects of different chemotherapy regimens on cognition and potential mechanisms and/or moderators of CRCI would be instrumental in designing more effective therapy regimens and evaluating the efficacy and cost-effectiveness of cognitive rehabilitation and supportive care programs.

Cognitive intra-individual variability in breast cancer survivors: A systematic review

Subjective and objective cognitive impairments in Breast Cancer Survivors (BCS) often do not correlate. One important contribution to the reported disparities may be the reliance on mean-based cognitive performance. Cognitive intra-individual variability (IIV) may provide important insights into these reported disparities. Cognitive IIV refers to the fluctuation in performance for an individual on either one cognitive task across a trial or dispersed across tasks within a neuropsychological test battery. The purpose of this systematic review was to search for and examine the literature on cognitive IIV in BCS. The PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) approach was used to search for all articles related to cognitive IIV in BCS. MEDLINE (via PubMed), Embase, and Scopus databases were searched using detailed search terms and strategies. Initially, 164 articles were retrieved but only 4 articles met the criteria for this systematic review. BCS differed from healthy controls in similar ways across the four studies, generally demonstrating similar performance but showing increased cognitive IIV for the more difficult tasks. Differences were enhanced later during chemotherapy. The four studies provide support for cognitive IIV as a useful measure to detect the subtle objective cognitive change often reported by BCS but frequently not detected by standard normed-based cognitive testing. Unexpectedly, measures of cognitive IIV were not consistently associated with self-reported measures of cognition.

Cognitive impairments associated with chemotherapy in women with breast cancer: a meta-analysis and meta-regression

Chemotherapy is one of the most widely used treatments for breast cancer (BC). However, there is evidence of side effects like cognitive changes related to the chemotherapy treatment. The aim of the study was not only to summarize the existing evidence on the relationship between chemotherapy and cognitive performance in women with BC but also to identify additional consequences and aspects associated with these impairments. We conducted a systematic review with meta-analysis and meta-regression to present updated information on the matter. We retrieved data from the databases PubMed, Web of Science, PsycINFO, CINAHL, and Scopus. Twenty studies comprising over 2,500 women were examined and the results indicated that chemotherapy can compromise cognition in women with BC (-1.10 OR [95%CI: -1.81 to -0.74], P<0.01), with working memory (-0.49 OR [95%CI: -0.85 to -0.13], P=0.03) being the most affected among the domains. Furthermore, additional data indicated that cognitive impairment is most likely amid women with BC having a lower education level (Q=4.85, P=0.02). Our results suggested that chemotherapy affects cognitive functions in women with BC, and certain characteristics can worsen the deterioration. A comprehensive study of women with breast cancer and existing predictors contributes to optimized personal journeys, elevated life prospects, and advanced care that can also aid prognosis and therapeutic approaches.

Moving intra-individual variability (IIV) towards clinical utility: IIV measured using a commercial testing platform

OBJECTIVES

Intra-individual variability (IIV), measured across repeated response times (RT) during continuous psychomotor tasks, is an early marker of cognitive change in the context of neurodegeneration. To advance IIV towards broader application in clinical research, we evaluated IIV from a commercial cognitive testing platform and compared it to the calculation approaches used in experimental cognitive studies.

METHODS

Cognitive assessment was administered in participants with multiple sclerosis (MS) during the baseline of an unrelated study. Cogstate was used for computer-based measures providing three timed-trial tasks measuring simple (Detection; DET) and choice (Identification; IDN) RT and working memory (One-Back; ONB). IIV for each task was automatically output by the program (calculated as a log₁₀-transformed standard deviation or "LSD"). We calculated IIV from the raw RTs using coefficient of variation (CoV), regression-based, and ex-Gaussian methods. The IIV from each calculation was then compared by rank across participants.

RESULTS

A total of n = 120 participants with MS aged 20-72 (Mean ± SD, 48.99 ± 12.09) completed the baseline cognitive measures. For each task, the interclass correlation coefficient was generated. Each ICC showed that LSD, CoV, ex-Gaussian, and regression methods clustered strongly (Average ICC for DET: 0.95 with 95% CI [0.93, 0.96]; Average ICC for IDN: 0.92 with 95% CI [0.88 to 0.93]; Average ICC for ONB: 0.93 with 95% CI [0.90 to 0.94]). Correlational analyses indicated the strongest correlation between LSD and CoV for all tasks (rs ≥ 0.94).

CONCLUSION

The LSD was consistent with research-based methods for IIV calculations. These findings support the use of LSD for the future measurement of IIV for clinical studies.

Differences in total cognition and cerebrovascular function in female breast cancer survivors and cancer-free women

Reduced cognition is often reported by breast cancer patients and survivors, but the mechanisms for this decline are yet to be determined. We compared the differences in cerebrovascular function and cognition in breast cancer survivors (n = 15) and cancer-free women (n = 15) matched by age and body mass index. Participants undertook anthropometric, mood, cardiovascular, exercise performance, strength, cerebrovascular, and cognitive measurements. Transcranial Doppler ultrasound was used to measure the cerebrovascular responsiveness (CVR) to physiological (hypercapnia; 5% carbon dioxide) and psychological stimuli. Breast cancer survivors had a lower CVR to hypercapnia (21.5 ± 12.8 vs 66.0 ± 20.9%, P < 0.001), CVR to cognitive stimuli (15.1 ± 1.5 vs 23.7 ± 9.0%, P < 0.001) and total composite cognitive score (100 ± 12 vs. 113 ± 7, P = 0.003) than cancer-free women. These parameters remained statistically different between the groups following adjustments for covariates using an analysis of co-variance. We observed significant correlations between multiple measures and exercise capacity the only variable positively correlated to all primary measures (CVR to hypercapnia, r = 0.492, P = 0.007; CVR to cognitive stimuli r = 0.555, P = 0.003; and total composite cognitive score, r = 0.625, P < 0.001). In this study, breast cancer survivors had lower cerebrovascular and cognitive function than age-matched cancer-free women, which may be attributable to the effects of cancer and cancer treatment on brain health.

A phase II single-arm trial of memantine for prevention of cognitive decline during chemotherapy in patients with early breast cancer: Feasibility, tolerability, acceptability, and preliminary effects

BACKGROUND

Cognitive difficulties have been described after chemotherapy for breast cancer, but there is no standard of care to improve cognitive outcomes in these patients. This trial examined the feasibility, tolerability, acceptability, and preliminary effects of memantine to prevent cognitive decline during chemotherapy for breast cancer.

METHODS

Patients with stage I-III breast cancer, scheduled for neo/adjuvant chemotherapy, completed a cognitive battery prior to and 4 weeks after completing chemotherapy. Memantine (10 mg BID) was administered concurrent with chemotherapy. Our primary cognitive outcome was visual working memory assessed by the Delayed Matching to Sample test. We used the Brief Medication Questionnaire to assess acceptability.

RESULTS

Of 126 patients approached, 56 (44%) enrolled. Forty-five (80%) received ≥1 dose of memantine and completed pre-post assessments. Seventy-six percent reported taking ≥90% of scheduled doses. Participants were mean age of 56, 77% White, and 57% had stage I disease. Sixty-four percent had stable or improved Delayed Matching to Sample test scores. Stable or improved cognition was observed in 87%-91% across objective cognitive domain composite measures. Sixty-six percent self-reported stable or improved cognitive symptoms. There were seven greater than or equal to grade 3 adverse events; two were possibly related to memantine. Only 5% reported that taking memantine was a disruption to their lives.

CONCLUSIONS

Memantine was well-tolerated and consistently taken by a large majority of patients receiving breast cancer chemotherapy. The majority demonstrated stable or improved cognition from pre- to post-assessment. Randomized trials are needed to determine memantine's efficacy to ameliorate cognitive loss.

TRIAL REGISTRATION

ClinicalTrials.gov NCT04033419.

A scoping review of cognitive assessment tools and domains for chemotherapy-induced cognitive impairments in cancer survivors

Backgrounds

Cancer survivors suffer from specific symptoms known as chemotherapy-induced cognitive impairments (CICIs). CICIs are difficult to capture with existing assessments such as the brief screening test for dementia. Although recommended neuropsychological tests (NPTs) exist, international consensus and shared cognitive domains of assessment tools are unknown. The aim of this scoping review was as follows: (1) to identify studies that assess CICIs in cancer survivors; (2) to identify shared cognitive assessment tools and domains by mapping the domains reported in studies using the International Classification of Functioning, Disability and Health (ICF) framework.

Methods

The study followed the recommendations made by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews. We searched the following three databases through October 2021: PubMed, CINAHL, and Web of Science. Prospective longitudinal or cross-sectional studies were selected to determine CICI-specific assessment tools for adult cancer survivors.

Results

Sixty-four prospective studies (36 longitudinal studies and 28 cross-sectional studies) were included after checking for eligibility. The NPTs were divided into seven main cognitive domains. The specific mental functions were often used in the order of memory, attention, higher-level cognitive functions, and psychomotor functions. Perceptual functions were used less frequently. In some ICF domains, shared NPTs were not clearly identified. In some different domains, the same NPTs were used, such as the trail making test and the verbal fluency test. When the association between the publishing year and the amount of NPT use was examined, it was found that the amount of tool use tended to decline over the publication years. The Functional Assessment of Cancer Therapy-Cognitive function (FACT-Cog) was a shared consensus tool among the patient-reported outcomes (PROs).

Conclusion

Chemotherapy-induced cognitive impairments are currently gaining interest. Shared ICF domains such as memory and attention were identified for NPTs. There was a gap between the publicly recommended tools and the tools actually used in the studies. For PROs, a clearly shared tool, FACT-Cog, was identified. Mapping the domains reported in studies using the ICF can help in the process of reviewing consensus on which NPTs may be used to target cognitive domains.

Systematic review registration

https://center6.umin.ac.jp/cgi-open-bin/ctr/ctr_view.cgi?recptno=R000053710, identifier UMIN000047104.

Brain Fog in Hypothyroidism: What Is It, How Is It Measured, and What Can Be Done About It

Background: Some levothyroxine (LT4)-treated hypothyroid patients report a constellation of persistent and distressing cognitive symptoms that has been termed brain fog. This narrative review focuses on attempts to define and measure hypothyroid-associated brain fog, summarize possible etiologies and contributing factors, present treatment options, and propose avenues for future research. Methods: Published literature was reviewed to summarize available information on patient-reported symptoms associated with brain fog in hypothyroidism, as well as objective evidence of impairment based on neurocognitive testing and functional imaging studies. Given the limited information specific for hypothyroid-associated brain fog, relevant data from other medical conditions associated with brain fog were also reviewed and incorporated into recommendations for clinical care and future research areas. Results: Hypothyroid-associated brain fog has not been well defined or quantitated, and the underlying pathophysiology is unclear. Symptoms vary among patients but commonly include fatigue, depressed mood, and cognitive difficulties in the areas of memory and executive function. Symptoms often predate the diagnosis of hypothyroidism, and the magnitude of cognitive impairment can range from mild to severe. Regardless of severity, these symptoms are associated with impaired quality of life and cause dissatisfaction with treatment, so often lead to requests for alternate therapies. Disease-specific and psychological factors impact the experience of brain fog in complex ways, including potential limitations in LT4 monotherapy, self-knowledge of a disease state, and expectations for therapeutic effects. Conclusions: Brain fog is a variable symptom complex in people with hypothyroidism, causing significant distress and diminished quality of life. In the absence of proven therapies, individualized treatment plans are recommended, which incorporate thyroid-specific, general medical, and psychosocial approaches. In particular, cognitive rehabilitation is an underutilized technique that is beneficial in other medical conditions associated with brain fog and could improve symptoms in hypothyroid people. The limitations in our current knowledge and questions presented throughout this review highlight a major need for clinical research in this understudied area. Future research should include attention to standardization of survey instruments to quantitate brain fog in hypothyroid people, as well as rigorously designed intervention studies.

Chemobrain in Breast Cancer: Mechanisms, Clinical Manifestations, and Potential Interventions

Among the potential adverse effects of breast cancer treatment, chemotherapy-related cognitive impairment (CRCI) has gained increased attention in the past years. In this review, we provide an overview of the literature regarding CRCI in breast cancer, focusing on three main aspects. The first aspect relates to the molecular mechanisms linking individual drugs commonly used to treat breast cancer and CRCI, which include oxidative stress and inflammation, reduced neurogenesis, reduced levels of specific neurotransmitters, alterations in neuronal dendrites and spines, and impairment in myelin production. The second aspect is related to the clinical characteristics of CRCI in patients with breast cancer treated with different drug combinations. Data suggest the incidence rates of CRCI in breast cancer vary considerably, and may affect more than 50% of treated patients. Both chemotherapy regimens with or without anthracyclines have been associated with CRCI manifestations. While cross-sectional studies suggest the presence of symptoms up to 20 years after treatment, longitudinal studies confirm cognitive impairments lasting for at most 4 years after the end of chemotherapy. The third and final aspect is related to possible therapeutic interventions. Although there is still no standard of care to treat CRCI, several pharmacological and non-pharmacological approaches have shown interesting results. In summary, even if cognitive impairments derived from chemotherapy resolve with time, awareness of CRCI is crucial to provide patients with a better understanding of the syndrome and to offer them the best care directed at improving quality of life.

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.

Chemotherapy-related cognitive impairment (CRCI) among early-stage breast cancer survivors in Malaysia

Introduction: Breast cancer survivors frequently develop cognitive impairment following chemotherapy which can significantly hamper their well-being, ability to function independently, and overall quality of life. Evidence of cognitive functioning in breast cancer survivors from lower and middle-income countries remains scarce. We examined the prevalence of cognitive impairment among Malaysian multiethnic early-stage breast cancer survivors one to three years post-chemotherapy.Methods: This cross-sectional study included 160 breast cancer survivors from the University Malaya Medical Center (UMMC). The cognitive assessments used included the Montreal Cognitive Assessment (MoCA-BM), the Rey Auditory and Verbal Learning Test (RAVLT-BM), and the digit span and arithmetic of the Working Memory Index (WMI) of Wechsler Adult Intelligence Scale-IV (WAIS-IV). Data were analyzed using independent sample t-tests and Pearson's correlation.Results: Our breast cancer survivors demonstrated poor performances in MoCA-BM (31.9%) RAVLT-BM, recall (53.8%), and WMI of WAIS-IV (51.3%) with 30.6% of them performed poorly in all three cognitive tests administered. There were no significant mean group differences in cognitive performances between <24 months after chemotherapy and ≥24 months after chemotherapy.Conclusions: A high proportion of breast cancer survivors exhibited poor performances in the cognitive assessments. Cognitive rehabilitation programmes tailored to the needs of these survivors should be incorporated into cancer care management.

Using a Digital Neuro Signature to measure longitudinal individual-level change in Alzheimer's disease: the Altoida large cohort study

Conventional neuropsychological assessments for Alzheimer's disease are burdensome and inaccurate at detecting mild cognitive impairment and predicting Alzheimer's disease risk. Altoida's Digital Neuro Signature (DNS), a longitudinal cognitive test consisting of two active digital biomarker metrics, alleviates these limitations. By comparison to conventional neuropsychological assessments, DNS results in faster evaluations (10 min vs 45-120 min), and generates higher test-retest in intraindividual assessment, as well as higher accuracy at detecting abnormal cognition. This study comparatively evaluates the performance of Altoida's DNS and conventional neuropsychological assessments in intraindividual assessments of cognition and function by means of two semi-naturalistic observational experiments with 525 participants in laboratory and clinical settings. The results show that DNS is consistently more sensitive than conventional neuropsychological assessments at capturing longitudinal individual-level change, both with respect to intraindividual variability and dispersion (intraindividual variability across multiple tests), across three participant groups: healthy controls, mild cognitive impairment, and Alzheimer's disease. Dispersion differences between DNS and conventional neuropsychological assessments were more pronounced with more advanced disease stages, and DNS-intraindividual variability was able to predict conversion from mild cognitive impairment to Alzheimer's disease. These findings are instrumental for patient monitoring and management, remote clinical trial assessment, and timely interventions, and will hopefully contribute to a better understanding of Alzheimer's disease.

Cognitive Effects and Depression Associated With Taxane-Based Chemotherapy in Breast Cancer Survivors: A Meta-Analysis

Purpose: This meta-analysis provides a longitudinal assessment of depression and cognitive impairment induced by taxane-based chemotherapy in women with breast cancer after 6 months of treatment. We highlighted the incidence and prevalence, the cognitive pattern in neuropsychological studies, and the relationship between chemotherapy-induced cognitive impairment and different risk factors. We estimated the effect sizes on each cognitive domain and differentiated effect sizes by each method of comparison of effects (i.e., baseline data, or control groups). Methods: The databases MEDLINE and Embase were searched for publications about taxane-related cognitive changes in patients with breast cancer published from 1980 to 2019. Cross-sectional and self-reported outcomes studies were excluded except for the depression item. Included studies were assessed for risk of bias with the Newcastle-Ottawa Scale. We estimated effect sizes for each cognitive domain and differentiated effect sizes by each method of comparison of effects. The review is reported in compliance with the PRISMA Statement; it was registered prospectively in PROSPERO as CRD42020163255. Results: Eleven studies meeting the criteria were analyzed, which resulted in a sample of 1,057 patients with breast cancer who received chemotherapy including 820 patients (77%) who received taxane-based chemotherapy. Attention and concentration, depression, and executive function domains had significant chemotherapy-induced impairment across all comparison types. Statistically significant improvement was found in language and verbal memory when comparing chemotherapy patients' test scores with baseline or matched controls. Taxane-based chemotherapy had a non-significant effect on processing speed, visual memory, visuospatial, and motor function domains. Conclusions: The occurrence of chemotherapy-induced cognitive impairment 6 months or more after the course of treatment in people with breast cancer is frequent in the domains of attention, executive function, and depression. Other domains appear stable or improve with time after treatment cessation.

Cognitive function in patients prior to undergoing allogeneic hematopoietic stem cell transplantation

PURPOSE

Cognitive impairment is common and consequential in patients with cancer who undergo allogeneic hematopoietic stem cell transplantation (HSCT). However, there is no standard of care for evaluating cognition in patients prior to or after receiving HSCT, and it is not known which patients are at highest risk for cognitive impairment. The objectives of this study were to describe cognitive function in patients prior to allogeneic HSCT and identify demographic, disease-related, and psychosocial factors associated with cognitive function.

METHODS

Prior to HSCT, participants completed the Montreal Cognitive Assessment (MoCA). We assessed bivariable associations between continuous MoCA scores and demographic, disease-related, and psychosocial variables using linear regression. Variables significant at the p < 0.2 level were adjusted for age, sex, and years of education in multiple linear regression analyses.

RESULTS

Over 50% of participants demonstrated evidence of cognitive impairment (MoCA < 26) prior to transplantation. When adjusted for demographic variables, two characteristics were significantly associated with worse cognitive function: the hematopoietic cell transplantation-comorbidity index score (p = 0.01) and history of alcohol or substance abuse (p = 0.02). Pre-HSCT cancer and cancer treatment-specific variables were not associated with cognitive function.

CONCLUSION

Cognitive impairment is common in patients scheduled to receive HSCT. Pre-transplantation evaluation of medical comorbidities and history of substance abuse may be important in identifying patients at risk for cognitive impairment. Further research characterizing the trajectory and impact of cognitive impairment on patient symptom burden and function may help improve outcomes.

Systematic review of cognitive sequelae of non-central nervous system cancer and cancer therapy

PURPOSE

The aim of this review is to provide an updated overview of chemotherapy-related cognitive impairment (CRCI) in patients with cancer outside central nervous system (CNS), its incidence and prevalence, the cognitive pattern in neuropsychological studies, neuroimaging findings, and the relationship between chemobrain and aging. Methodological limitations of studies are also discussed.

METHODS

This review was guided by the PRISMA statement. The MEDLINE and Scopus databases were employed to search articles about CRCI in non-CNS cancer patients published from January 2004 to September 2019. Two types of research were reviewed: prospective studies addressing the effects of chemotherapy on cognition and systematic reviews about factors related with CRCI, also as neuroimaging findings and current available treatments.

RESULTS

Fifty-nine studies meeting the criteria were analyzed: 47 were longitudinal studies on cancer and cognition and 12 were reviews on risk factors, neuroimaging, and treatment. The majority of studies find cognitive impairment in patients with cancer treated with chemotherapy. The body of the literature on breast cancer is the most abundant, but there are also studies on colorectal, testicular, and lung cancer. Neuroimaging studies show changes in structure and activation in patients undergoing chemotherapy. Non-pharmacological treatment is effective for improving cognition and quality of life.

CONCLUSIONS

The occurrence of CRCI during the course of treatment in people with different types of cancer is frequent. Some risk factors have been identified, but CRCI is a complex phenomenon, with mediating factors related to cancer and treatment and moderating factors related with lifestyle and health.

IMPLICATIONS FOR CANCER SURVIVORS

This review highlights the importance of recognizing that this cognitive dysfunction is frequent, mild to moderate in nature but with great impact on quality of life.

Psychostimulants for cancer-related cognitive impairment in adult cancer survivors: a systematic review and meta-analysis

BACKGROUND

Cognitive impairment is recognized as a common symptom experienced by cancer survivors which impacts on quality of life (QoL) and day-to-day activities. One of the treatment options is the use of psychostimulants but the evidence supporting its use remains unclear.

OBJECTIVES

To identify the level of evidence of psychostimulants' effect on the management of cognitive impairment in adult cancer survivors.

METHODS

Electronic databases (MEDLINE, EMBASE, CENTRAL, CINAHL) and reference lists of relevant reviews were searched from inception to December 2017, with no language restrictions applied. Randomized controlled trials (RCTs), evaluating the effect of psychostimulants on cognitive impairment among cancer patients with no primary or secondary brain tumor or brain radiation, were included. The primary outcome was cognitive function changes, whereas secondary outcomes were adverse events (AEs) and QoL.

RESULTS

Six RCTs were included: three studies investigating methylphenidate and three modafinil, with a total of 244 and 146 patients, respectively. Due to important differences in methodologies between studies, a meta-analysis was assumed inappropriate for the primary outcome. A narrative synthesis was performed. One study using methylphenidate and two using modafinil demonstrated improvements in some cognitive functions as measured by objective cognitive assessment tests. Psychostimulants did not improve QoL and were not associated with more AEs.

CONCLUSION

To date, limited evidence is available to estimate the usefulness (or lack) of psychostimulants on cognitive function in this population.

Effectiveness of Intraindividual Variability in Detecting Subtle Cognitive Performance Deficits in Breast Cancer Patients

OBJECTIVES

The purpose of this study was to determine if intraindividual variability would be more sensitive than speed or accuracy in detecting subtle cancer-related cognitive disturbance.

METHODS

Data were from a previous study in which 60 breast cancer (BC) patients underwent neuropsychological assessment before commencement of chemotherapy and again following each chemotherapy cycle. Sixty healthy controls were tested at equivalent intervals. Hierarchical linear modeling was used to compare the BC and control groups in terms of accuracy, mean reaction time, and intraindividual variability in reaction time on a computerized continuous performance test with three conditions: a simple reaction time task, a "1-back" task, and a "2-back" task.

RESULTS

An increase in accuracy and response speed over sessions was noted on some tasks in the sample as a whole but there were no differences in these parameters between the BC patients and the controls on any condition. There was a significant group difference in change in intraindividual variability across sessions (i.e., a "group × session interaction"), albeit only on the most complex "2-back" task. Intraindividual variability declined in the control group (i.e., consistency improved with practice) but this practice effect was significantly attenuated in the BC patients. There was no main effect of group on the "2-back" task.

CONCLUSIONS

Results support our hypothesis that intraindividual variability is a more sensitive indicator of subtle cognitive disturbance than conventional speed or accuracy measures and may have potential in the assessment of mild cognitive impairment in patients with non-central nervous system cancers. (JINS, 2018, 24, 724-734).

Executive functioning impairment in women treated with chemotherapy for breast cancer: a systematic review

PURPOSE

Women with breast cancer have reported adverse cognitive effects following chemotherapy. Evidence is mixed on whether executive functioning is particularly impaired in women treated with chemotherapy, in part due to the wide range of tasks used to measure executive processes. We performed a systematic review of the published literature to evaluate whether some subcomponents of executive functioning are more vulnerable to impairment than others among breast cancer survivors who had been treated with chemotherapy.

METHODS

Studies published as of April 2017 were identified using three electronic databases (MEDLINE, PsycINFO, and Web of Science) and a manual search of relevant reference lists. The methodological quality of included studies was assessed using a checklist of predefined criteria.

RESULTS

Of 1280 identified articles, a total of 41 were included for review. Study findings were categorized into three primary subdomains of executive functioning: inhibition, shifting, and updating. Although there was heterogeneity in the neuropsychological measures used to assess executive functioning, tests could be grouped into the subcomponents they assessed. Inhibition appears relatively spared from the effects of chemotherapy, whereas impairments in shifting and updating are more commonly found following chemotherapy.

CONCLUSIONS

Examination of subcomponents of executive functioning is recommended to better characterize the nature of executive dysfunction in women treated with chemotherapy. Future studies should include executive functioning tasks of varying complexity, use of multiple tasks to increase reliability, and alternative indices to capture performance, such as within-person variability.