Cerebral hyporesponsiveness and cognitive impairment 10 years after chemotherapy for breast cancer

Self-perceived cognitive impairment in the first year after breast cancer and the identification of at-risk patients

PURPOSE

This study investigated self-reported clinically relevant cognitive impairment of breast cancer patients in routine clinical care and assessed factors associated with new-onset clinically relevant cognitive impairment.

METHODS

Cognitive functioning was assessed before start of any treatment (T0) and at 6 (T6) and 12 (T12) months after diagnosis. Cognitive functioning (CF) was measured on a scale of 0-100 with the EORTC QLQ-C30 questionnaire, and the EORTC pre-defined threshold for clinical importance. Multivariable logistic regression analyses was used to identify factors associated with new-onset clinically relevant cognitive impairment at T6 ((CF > 75 at T0 and CF < 75 at T6 and T12) or (CF > 75 at T0 and T6 and <75 at T12)).

RESULTS

Pre-treatment, 21% of patients reported clinically relevant cognitive impairment. At T12, percentage was 32%; 20% of patients reported new-onset clinically relevant cognitive impairment at T6 and/or T12. New-onset clinically relevant cognitive impairment was associated with chemo(immuno)therapy and impairment in role and emotional functioning. Younger patients and patients receiving chemo(immuno)therapy were more likely to report new-onset clinically relevant cognitive impairment post treatment.

CONCLUSION

One in five breast cancer patients reported clinically relevant cognitive problems before start of treatment. This percentage further increased within the first year, particularly among patients treated with chemo(immuno)therapy. One in five patients reported new-onset clinically relevant cognitive impairment. Ultimately, these patients may benefit from systematic monitoring and potential referral to interventions.

Work status changes and associated factors in a nationwide sample of Norwegian long-term breast cancer survivors

PURPOSE

The study aims to describe work status at diagnosis and 8 years post-diagnosis in a nationwide sample of breast cancer survivors (BCSs), and investigate associated and self-reported factors of reduced work status.

METHODS

Women aged 20-65 years when diagnosed with stage I-III breast cancer (BC) in 2011 or 2012 were invited to participate in a questionnaire study in 2019 (n = 2803), of whom 49% (n = 1361) responded. For this sub-study, we included 974 BCSs below the legal retirement age in Norway (< 67 years) at survey and with complete work status data. Reduced work status was defined as being in paid work at BC diagnosis and not working at time of survey. Logistic regression analyses were applied to identify factors associated with reduced work status.

RESULTS

Of BCSs who were in paid work at diagnosis (n = 845), 63% maintained their work status to 8 years later. Reduced work status was associated with not living with children (OR .44, 95% CI .24-.82), age (OR 1.16, 95% CI 1.11-1.21), chemotherapy (OR 2.83, 95% CI 1.24-6.61), > 2 comorbid conditions (OR 2.27, 95% CI 1.16-4.32), cognitive function (OR .99, 95% CI .98-.99), fatigue (OR 1.02, 95% CI 1.01-1.03), and neuroticism (OR 1.57, 95% CI 1.00-2.46). BC and late effects were reported as reasons for reduced work status and disability.

CONCLUSIONS

The majority of BCSs who were in paid work at diagnosis were working 8 years later.

IMPLICATIONS FOR CANCER SURVIVORS

Our results suggest a need to focus on fatigue and reduced cognitive function among long-term BCSs, with the ultimate aim of improving work sustainability.

Longitudinal trajectory of amplitude of low-frequency fluctuation changes in breast cancer patients during neoadjuvant chemotherapy-A preliminary prospective study

There is growing evidence that the amplitude of low-frequency fluctuation (ALFF) changes in breast cancer patients after chemotherapy. However, longitudinal changes in ALFF during chemotherapy are unclear. To assess the trajectory of ALFF changes during chemotherapy, 36 breast cancer patients underwent both resting-state functional magnetic resonance imaging and neuropsychological testing at three time points, including before neoadjuvant chemotherapy (NAC) (time point 0, TP0), after one cycle of NAC (before the second cycle of NAC, TP1), and upon completion of NAC (pre-operation, TP2). Healthy controls (HC) received the same assessments at matching time points. We compared the longitudinal changes of ALFF in the NAC and two HC groups. In the NAC group, compared with TP0, ALFF values in the right orbital part of the inferior frontal gyrus, left medial orbital part of the superior frontal gyrus, right insula, left medial part of the superior frontal gyrus, and right middle frontal gyrus declined significantly at TP1 and TP2. Compared with TP1, there were no significant changes in ALFF values at TP2. In the two HC groups, there were no significant changes in ALFF at corresponding intervals. We concluded that for breast cancer patients receiving NAC, ALFF values declined significantly in some brain regions after one cycle of NAC and then remained stable until the completion of NAC, and most of the brain regions with ALFF changes were located in the frontal lobe.

Long-term changes of cognitive impairment among older breast cancer survivors

PURPOSE

Cancer-related cognitive impairment is common during cancer treatment; however, it is unclear whether the impairment persists over time. Our study aimed to examine long-term cognitive impairment among older breast cancer survivors.

METHODS

Participants included 2420 community-dwelling women aged 65 years or older at enrollment (1986-1988) (404 breast cancer cases and 1:5 matched cancer-free controls) from the Study of Osteoporotic Fractures. Participants were followed for 20 years with measured cognitive function repeated up to 6 times. Cognitive impairment was defined by the Modified Mini-Mental State Examination and Trail Making Test B. Generalized linear models were used to model risk of cognitive impairment in relation to breast cancer status and time from breast cancer diagnosis.

RESULTS

Compared with controls, cognitive impairment in women with breast cancer significantly accelerated after cancer diagnosis. We also observed a more pronounced cognitive impairment after cancer diagnosis for women diagnosed with breast cancer at age ≥ 80 years or at advanced stage for both measures.

CONCLUSION

Our study with more than 20 years of follow-up data found that breast cancer survivors had accelerated cognitive impairment after cancer diagnosis, especially among women diagnosed at older age or at advanced stage, relative to women without cancer.

IMPLICATIONS FOR CANCER SURVIVORS

Breast cancer survivors may be encouraged to engage in both physical activity and cognitive training.

Can more be done? - A qualitative study of breast cancer survivors' perspectives on regular walking exercise to improve post-chemotherapy neurotoxicity impairments

PURPOSE

Chemotherapy-induced neurotoxicity in breast cancer survivors requires attention as their population are increasing. Limited qualitative study is known about breast cancer survivors' perspectives on regular walking exercise to improve post-chemotherapy neurotoxicity impairments in their free-living setting. This study explored regular walking exercise to improve post-chemotherapy neurotoxicity impairments from breast cancer survivors' perspectives.

METHODS

A qualitative descriptive study was conducted. A purposive sample of 15 participants experiencing neurotoxicity impairments was invited to semi-structured interviews. Textual interview data were managed in NVivo. Content analysis was performed.

RESULTS

Participants were aged 39-68 and had received 4-8 cycles of chemotherapy. Most (86.7%, n = 13) reported engaging in regular walking exercise. Four main categories emerged from the data: (1) perceived effects of regular exercise on neurotoxicity impairments, (2) unmet information needs, (3) regular walking habit being self-sustained, and (4) enablers and constraints of regular walking exercise.

CONCLUSIONS

Walking exercise, as commonly employed by participants in their free-living setting, was the essence in the management of chemotherapy-induced neurotoxic conditions during survivorship. Participants undertaking walking exercise lacked informed and individualized information about the regular walking exercise regime, and vigilance to evaluate post-exercise neurotoxic conditions. These might be the unmet needs of this research area and in clinical practice. Assessing and addressing individualized endeavors in a walking exercise regime will continue to be a vital component of cancer supportive care to fill the unmet information needs in survivorship.

Neuroimaging based biotypes for precision diagnosis and prognosis in cancer-related cognitive impairment

Cancer related cognitive impairment (CRCI) is commonly associated with cancer and its treatments, yet the present binary diagnostic approach fails to capture the full spectrum of this syndrome. Cognitive function is highly complex and exists on a continuum that is poorly characterized by dichotomous categories. Advanced statistical methodologies applied to symptom assessments have demonstrated that there are multiple subclasses of CRCI. However, studies suggest that relying on symptom assessments alone may fail to account for significant differences in the neural mechanisms that underlie a specific cognitive phenotype. Treatment plans that address the specific physiologic mechanisms involved in an individual patient's condition is the heart of precision medicine. In this narrative review, we discuss how biotyping, a precision medicine framework being utilized in other mental disorders, could be applied to CRCI. Specifically, we discuss how neuroimaging can be used to determine biotypes of CRCI, which allow for increased precision in prediction and diagnosis of CRCI via biologic mechanistic data. Biotypes may also provide more precise clinical endpoints for intervention trials. Biotyping could be made more feasible with proxy imaging technologies or liquid biomarkers. Large cross-sectional phenotyping studies are needed in addition to evaluation of longitudinal trajectories, and data sharing/pooling is highly feasible with currently available digital infrastructures.

Chemobrain: An accelerated aging process linking adenosine A2A receptor signaling in cancer survivors

Chemotherapy has a significant positive impact in cancer treatment outcomes, reducing recurrence and mortality. However, many cancer surviving children and adults suffer from aberrant chemotherapy neurotoxic effects on learning, memory, attention, executive functioning, and processing speed. This chemotherapy-induced cognitive impairment (CICI) is referred to as "chemobrain" or "chemofog". While the underlying mechanisms mediating CICI are still unclear, there is strong evidence that chemotherapy accelerates the biological aging process, manifesting as effects which include telomere shortening, epigenetic dysregulation, oxidative stress, mitochondrial defects, impaired neurogenesis, and neuroinflammation, all of which are known to contribute to increased anxiety and neurocognitive decline. Despite the increased prevalence of CICI, there exists a lack of mechanistic understanding by which chemotherapy detrimentally affects cognition in cancer survivors. Moreover, there are no approved therapeutic interventions for this condition. To address this gap in knowledge, this review attempts to identify how adenosine signaling, particularly through the adenosine A2A receptor, can be an essential tool to attenuate accelerated aging phenotypes. Importantly, the adenosine A2A receptor uniquely stands at the crossroads of cancer treatment and improved cognition, given that it is widely known to control tumor induced immunosuppression in the tumor microenvironment, while also posited to be an essential regulator of cognition in neurodegenerative disease. Consequently, we propose that the adenosine A2A receptor may provide a multifaceted therapeutic strategy to enhance anticancer activity, while combating chemotherapy induced cognitive deficits, both which are essential to provide novel therapeutic interventions against accelerated aging in cancer survivors.

Cardiorespiratory fitness is associated with hippocampal resting state connectivity in women newly diagnosed with breast cancer

Background

Breast cancer and its treatment are associated with aberrant patterns of resting state functional connectivity (rsFC) between the hippocampus and several areas of the brain, which may account for poorer cognitive outcomes in patients. Higher cardiorespiratory fitness (CRF) has been associated with enhanced rsFC and cognitive performance; however, these associations have not been well studied in breast cancer. We examined the relationship between CRF, rsFC of the hippocampus, and cognitive performance among women newly diagnosed with breast cancer.

Methods

Thirty-four postmenopausal women newly diagnosed with Stage 0-IIIa breast cancer (Mage = 63.59 ± 5.73) were enrolled in a 6-month randomized controlled trial of aerobic exercise vs. usual care. During baseline assessments, participants completed functional brain imaging, a submaximal CRF test, and cognitive testing. Whole-brain, seed-based analyses were used to examine the relationship between CRF and hippocampal rsFC, with age, years of education, and framewise displacement included as covariates. Cognition was measured with a battery of validated neurocognitive measures, reduced to seven composite factors.

Results

Higher CRF was positively associated with greater rsFC of the hippocampus to a cluster within the dorsomedial and dorsolateral frontal cortex (z-max = 4.37, p = 0.003, cluster extent = 1,020 voxels). Connectivity within cluster peaks was not significantly related to cognitive factors (all ps > 0.05).

Discussion

CRF was positively associated with hippocampal rsFC to frontal cortex structures, comprising a network of regions commonly suppressed in breast cancer. Future longitudinal research is needed to explore whether baseline rsFC predicts long-term cognitive resilience in breast cancer.

Psychological distress is involved in CRCI in breast cancer survivors via mediating cytokine levels

BACKGROUND

Cancer-related cognitive impairment (CRCI) is a frequent consequence in breast cancer survivors after chemotherapy and lowers their quality of life (QOL). Psychological distress is frequently experienced by breast cancer survivors. There are currently few studies investigating the role of psychological distress in the genesis of CRCI.

METHODS

In total, 122 breast cancer survivors after standard chemotherapy within a year were recruited and assessed using the Psychological Distress Thermometer (DT). Sixty breast cancer survivors had non-psychological distress (NPD group) and sixty-two breast cancer survivors with psychological distress (PD group). The scores of the Mini-Mental State Examination (MMSE), prospective and retrospective memory (PM and RM) Questionnaire (PRMQ), and Functional Assessment of Cancer Therapy-General (FACT-G) and the levels of cytokines including interleukin-1 beta (IL-1β), tumor necrosis factor-alpha (TNF-α), and interleukin-4 (IL-4) were compared between the two groups. Using PROCESS, we investigated whether psychological distress predicted cognitive function based on MMSE through IL-1β, TNF-α, and IL-4.

RESULTS

The PD group had higher scores on RM, PM, and FACT-G and lower scores on MMSE than the NPD group (t = -11.357, t = -10.720, t = -15.419, t = 10.162, respectively; p < 0.05). Meanwhile, a higher level of IL-1β, TNF-α, and IL-4 was observed in the PD group than in the NPD group (t = -3.961, t = -3.396, t = -3.269, respectively; p < 0.05). The link between psychological distress and cognitive function as measured by the MMSE was also mediated by IL-1β, TNF-α, and IL-4 (effect size: 26%, 25%, and 24%).

CONCLUSION

Breast cancer patients with psychological distress displayed poor cognitive function, poor memory, and inferior quality of life, which was accompanied by higher cytokine levels of IL-1β, TNF-α, and IL-4. This study demonstrated IL-1β, TNF-α, and IL-4 as potential pathways to CRCI in response to ongoing psychological distress, which provided evidence for the involvement of psychological distress in CRCI in breast cancer survivors.

Cortical thinning in chemotherapy-treated older long-term breast cancer survivors

Cognitive decline is an increasing issue for cancer survivors, especially for older adults, as chemotherapy affects brain structure and function. The purpose of this single center study was to evaluate alterations in cortical thickness and cognition in older long-term survivors of breast cancer who had been treated with chemotherapy years ago. In this prospective cohort study, we enrolled 3 groups of women aged ≥ 65 years with a history of stage I-III breast cancer who had received adjuvant chemotherapy 5 to 15 years ago (chemotherapy group, C +), age-matched women with breast cancer but no chemotherapy (no-chemotherapy group, C-) and healthy controls (HC). All participants underwent brain magnetic resonance imaging and neuropsychological testing with the NIH Toolbox Cognition Battery at time point 1 (TP1) and again at 2 years after enrollment (time point 2 (TP2)). At TP1, there were no significant differences in cortical thickness among the 3 groups. Longitudinally, the C + group showed cortical thinning in the fusiform gyrus (p = 0.006, effect size (d) = -0.60 [ -1.86, -0.66]), pars triangularis (p = 0.026, effect size (d) = -0.43 [-1.68, -0.82]), and inferior temporal lobe (p = 0.026, effect size (d) = -0.38 [-1.62, -0.31]) of the left hemisphere. The C + group also showed decreases in neuropsychological scores such as the total composite score (p = 0.01, effect size (d) = -3.9726 [-0.9656, -6.9796], fluid composite score (p = 0.03, effect size (d) = -4.438 [-0.406, -8.47], and picture vocabulary score (p = 0.04, effect size (d) = -3.7499 [-0.0617, -7.438]. Our results showed that cortical thickness could be a candidate neuroimaging biomarker for cancer-related cognitive impairment and accelerated aging in older long-term cancer survivors.

Remote, Computerised Cognitive Assessment for Breast Cancer- and Treatment-Related Cognitive Dysfunction: Psychometric Characteristics of the Cogsuite Neurocognitive Battery

OBJECTIVE

Cancer-related cognitive dysfunction (CRCD) is a significant concern for breast cancer survivors. The Cogsuite battery was developed to improve sensitivity to CRCD with the use of cognitive experimental measures, clarify specific cognitive processes impacted and to be capable of being administered either in-office or remotely.

METHODS

In sum, 357 breast cancer survivors and non-cancer controls completed the Cogsuite Battery in-office (n = 76) or remotely (n = 281). Measure validity, sensitivity to demographic factors, correlations with standard neuropsychological measures and intercorrelations of Cogsuite variables were assessed. Test-retest reliability was evaluated in-office (n = 24) and remotely (n = 80).

RESULTS

Test-retest reliability for most variables assessed was adequate to strong. Internal validity, as indicated by the confirmation of expected condition effects within each measure, was established for all measures. Assessment of external validity found age, but not education, was a significant predictor in the majority of measures. Assessment of criterion validity found that Cogsuite variables were correlated with standard measures in psychomotor speed, working memory and executive function, but not associated with self-reported cognition or mood.

CONCLUSIONS

Cogsuite is reliable and valid, and is sensitive to the effects of increasing age on cognition. The addition of the Cogsuite battery to standard assessment may improve sensitivity to CRCD and identify underlying processes that may be affected. Remote use of the Cogsuite battery in appropriate settings will lessen the burden for providers, researchers and survivors in research and clinical contexts.

Cognitive function is well preserved in a cohort of breast cancer survivors: Roles of cognitive reserve, resilience, and general health

Many patients return to cognitively demanding work after breast cancer treatments. This makes treatment-related cognitive decline an important research topic. Psychological resilience, cognitive reserve and better perceived general health may work as protective factors against cognitive decline. The aim of this study was to analyse whether these factors are associated with cognitive function among such women.

Data from 384 breast cancer survivors who underwent neuropsychological examination at follow-up 4–9 years after surgery were used. The neurocognitive domain variable Learning and Memory was computed from Wechsler Memory Scale-III subtests Learning and Delayed Recall. Another variable, Attention, Processing speed and Executive function, was computed from semantic and verbal fluency tests, Trail Making Test A and B, and Wechsler Adult Intelligence Test-IV subtest Coding. Psychological resilience was measured with Resilience Scale-14, and perceived general health with RAND-36 subitem General Health.

Results

showed that levels of cognitive performance and general health were statistically higher than population average. Resilience and general health in separate models were associated with Attention, Processing speed and Executive function (β = 0.14, p = 0.01; β = 0.13, p = 0.03, respectively). When added simultaneously in the same model, resilience was significant (β = 0.13, p = 0.04), but general health was not. These associations were nonsignificant after controlling for confounding factors. Learning and Memory was not associated with resilience or general health.

Future research should focus on longitudinal studies identifying patients at a high risk of developing cognitive decline after breast cancer treatments and on preventive and therapeutic approaches.

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401 women were neuropsychologically examined 4–9 years after breast cancer surgery.

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Their cognitive performance was on average well preserved.

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Psychological Resilience associated with better cognitive performance in one domain.

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The association between General Health and cognition was less prominent.

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High education level might protect against cognitive decline after breast cancer.

Initial encoding deficits with intact memory retention in older long-term breast cancer survivors

PURPOSE

Cancer survivors frequently report significant forgetfulness, but standard neuropsychological tests often fail to detect primary memory deficits. Past research has suggested survivors may misattribute forgetfulness to memory decay rather than impairments in initial encoding, but no studies have tested whether this pattern is evident in older survivors, who are more vulnerable to age-related memory difficulties. We examined whether long-term breast cancer survivors treated in older adulthood demonstrate deficits in initial encoding, as opposed to increased rates of memory decay, relative to non-cancer controls.

METHODS

Three hundred twenty-eight breast cancer survivors age 60 and above, 5-15 years post-treatment, and 162 age-matched non-cancer controls completed list learning and narrative memory assessments at four time-points over 2 years. Performance on learning trials and delayed recall was analyzed at each time-point to assess group differences in memory encoding, and memory decay was assessed by analyzing changes in performance across delays.

RESULTS

Univariate ANCOVAs correcting for age and education showed that survivors had worse initial encoding performance across multiple time-points, which were compensated for with multiple learning trials to produce recall performance comparable to controls. There were no significant group differences in memory decay.

CONCLUSIONS

Older long-term breast cancer survivors exhibit a consistent pattern of initial encoding deficits, but memory retention was comparable to controls. Future research should consider the role of encoding deficits and age-related factors when evaluating cognitive function in older survivors.

IMPLICATIONS FOR CANCER SURVIVORS

Commonly reported memory problems may stem from encoding deficits in older long-term cancer survivors.

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

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

Signal Variability and Cognitive Function in Older Long-Term Survivors of Breast Cancer with Exposure to Chemotherapy: A Prospective Longitudinal Resting-State fMRI Study

The purpose of this study was to assess the effect of chemotherapy on brain functional resting-state signal variability and cognitive function in older long-term survivors of breast cancer. This prospective longitudinal study enrolled women age ≥ 65 years of age who were breast cancer survivors after exposure to chemotherapy (CH), age-matched survivors not exposed to chemotherapy, and healthy controls. Participants completed resting-state functional brain MRI and neurocognitive testing upon enrollment (timepoint 1, TP1) and again two years later (timepoint 2, TP2). There were 20 participants in each of the three groups at TP1. The CH group showed a significant decrease in SD_BOLD (blood-oxygen-level-dependent signal variability in standard deviation) in the right middle occipital gyrus (ΔSD_BOLD = -0.0018, p = 0.0085, q (p_FDR) = 0.043 at MNI (42, -76, 17)) and right middle temporal gyrus (ΔSD_BOLD = -0.0021, p = 0.0006, q (p_FDR) = 0.001 at MNI (63, -39, -12)). There were negative correlations between the crystallized composite scores and SD_BOLD values at the right inferior occipital gyrus (correlation coefficient r = -0.84, p = 0.001, q (p_FDR) = 0.016) and right middle temporal gyrus (r = -0.88, p = 0.000, q (p_FDR) = 0.017) for the CH group at TP1. SD_BOLD could be a potentially useful neuroimaging marker for older long-term survivors of breast cancer with exposure to chemotherapy.

Prevalence of Breast Cancer Survivors Among Canadian Women

BACKGROUND

The 49% decrease in breast cancer mortality since 1986 has increased the number of breast cancer survivors requiring survivorship care. The purpose of this analysis was to estimate the 2022 prevalence of breast cancer survivors diagnosed within the past 15 years among Canadian women.

METHODS

We extracted the projected female breast cancer cases from 2007 to 2021 and rates of net survival (competing noncancer causes of death removed) from the Canadian Cancer Society's statistical reports. Overall survival was extracted from published Ontario data. Using known survival rates for 1, 5, 10, and 15 years, we interpolated remaining years and applied the corresponding net and overall survival rates to the projected cases for each year from 2007 to 2021 to determine survivors in 2022. Prevalence for predefined age groups was also calculated. As an example of excess healthcare costs attributable to breast cancer, we calculated the excess costs of heart failure hospitalizations.

RESULTS

From 2007 to 2021, there were 370,756 breast cancer cases. Using net survival, 318,429 (85.9%) of these patients were projected to survive breast cancer by 2022, a prevalence of 2.1% of Canadian women. Using overall survival, prevalence was 1.8%. Prevalence increased with age group, from 0.01% of those aged 20 to 24 years to 12.7% of those aged ≥90 years, and from 1.0% among the working and/or child-raising (age 20-64 years) to 5.4% among elderly populations (age ≥65 years). Among these survivors, 24.9% of projected heart failure hospitalizations would be in excess of those among matched control subjects, with projected excess costs of $16.5 million CAD. Given the excess healthcare costs, potential for reduced contributions to the workforce, and reduced quality of life associated with long-term impairments and risk of excess non-breast cancer death, enhanced breast cancer survivorship care is warranted.

CONCLUSIONS

With an overall prevalence of 2% among Canadian women, breast cancer survivors represent an increasing segment of the working-age and elderly populations.

Neural correlates in functional brain mapping among breast cancer survivors receiving different chemotherapy regimens: a qEEG/HEG-based investigation

BACKGROUND

Post-chemotherapy cognitive impairment commonly known as 'chemobrain' or 'chemofog' is a well-established clinical disorder affecting various cognitive domains including attention, visuospatial working memory, executive function, etc. Although several studies have confirmed the chemobrain in recent years, scant experiments have evaluated the potential neurotoxicity of different chemotherapy regimens and agents. In this study, we aimed to evaluate the extent of attention deficits, one of the commonly affected cognitive domains, among breast cancer patients treated with different chemotherapy regimens through neuroimaging techniques.

METHODS

Breast cancer patients treated with two commonly prescribed chemotherapy regimens, Adriamycin, Cyclophosphamide and Taxol and Taxotere, Adriamycin and Cyclophosphamide, and healthy volunteers were recruited. Near-infrared hemoencephalography and quantitative electroencephalography assessments were recorded for each participant at rest and during task performance to compare the functional cortical changes associated with each chemotherapy regimen.

RESULTS

Although no differences were observed in hemoencephalography results across groups, the quantitative electroencephalography analysis revealed increased power of high alpha/low beta in left fronto-centro-parietal regions involved in dorsal and ventral attention networks in the Adriamycin, Cyclophosphamide and Taxol-treated group compared with the Taxotere, Adriamycin and Cyclophosphamide and control group. The Adriamycin, Cyclophosphamide and Taxol-treated cases had the highest current source density values in dorsal attention network and ventral attention network and ventral attention network-related centers in 10 and 15 Hz associated with the lowest Z-scored Fast Fourier Transform coherence in the mentioned regions.

CONCLUSIONS

The negatively affected neurocognitive profile in breast cancer patients treated with the Adriamycin, Cyclophosphamide and Taxol regimen proposes presumably neurotoxic sequelae of this chemotherapy regimen as compared with the Taxotere, Adriamycin and Cyclophosphamide regimen.

Transdisciplinary Preliminary Evaluation of Goal Maintenance in Cancer-Related Cognitive Impairment

Women treated for breast cancer often experience decreases in executive functioning, including goal maintenance, which interferes with daily living. The objective of this study was to conduct a preliminary comparison of cognitive neuroscience assessment performance with neuropsychological, self-report, and performance-based assessments of goal maintenance in women with breast cancer. Women treated for breast cancer in the preceding 3 years completed a battery of cognitive assessments. Relationships between assessment methods were evaluated using Spearman rho correlations. Consistent with prior literature, the AY condition of the Dot Pattern Expectancy (DPX) assessment had the highest error rate. No consistent relationships between the DPX and other methods of assessment were identified; however, some moderate correlations were identified between assessments. Women treated for breast cancer present with DPX performance patterns similar to that of healthy controls in past literature. A larger study is required to confirm relationships between measures of goal maintenance across disciplines.

Chemotherapy and Related Female Sexual Dysfunction: A Review of Literature

Context: Cancer is a detrimental illness that affects patients’ quality of life and other aspects of a healthy life. Chemotherapy has been shown to have a direct and indirect effect on the sex organs of women. Evidence Acquisition: We searched in databases including PubMed, Scopus, and Google scholar. The keywords for our search were as follows: “Chemotherapy” OR “Cancer treatment” AND “Sexual dysfunction “OR “Sexuality” OR "libido” OR "dyspareunia" OR "orgasmic disorder" OR "sexual disorder". We evaluated the articles based on their abstract and 92 studies were selected and used in the present study. Results: Chemotherapeutic agents damage ovaries and could cause premature ovarian failure. Furthermore, chemotherapy disturbs the femininity aspects of patients and reduces their libido. In this review article, we aimed at a better understanding the effect of chemotherapy on the sexual function of female cancer survivals. Conclusions: In conclusion, chemotherapy is one of the most common cancer treatments affecting sexual health aspects, such as decreased libido, arousal and orgasm, dyspareunia, dysfunction of the sexual response cycle before puberty, and vulvovaginal atrophy. However, many patients are reluctant to discuss their sexual problems.

Temporal Dynamics of Resting-state Functional Networks and Cognitive Functioning following Systemic Treatment for Breast Cancer

Many women with breast cancer suffer from a decline in memory and executive function, particularly after treatment with chemotherapy. Recent neuroimaging studies suggest that changes in network dynamics are fundamental in decline in these cognitive functions. This has, however, not yet been investigated in breast cancer patients. Using resting state functional magnetic resonance imaging, we prospectively investigated whether changes in dynamic functional connectivity were associated with changes in memory and executive function. We examined 34 breast cancer patients that received chemotherapy, 32 patients that did not receive chemotherapy, and 35 no-cancer controls. All participants were assessed prior to treatment and six months after completion of chemotherapy, or at similar intervals for the other groups. To assess memory and executive function, we used the Hopkins Verbal Learning Test – Immediate Recall and the Trail Making Test B, respectively. Using a sliding window approach, we then evaluated dynamic functional connectivity of resting state networks supporting memory and executive function, i.e. the default mode network and frontoparietal network, respectively. Next, we directly investigated the association between cognitive performance and dynamic functional connectivity. We found no group differences in cognitive performance or connectivity measures. The association between dynamic functional connectivity of the default mode network and memory differed significantly across groups. This was not the case for the frontoparietal network and executive function. This suggests that cancer and chemotherapy alter the role of dynamic functional connectivity in memory function. Further implications of these findings are discussed.

Alterations in degree centrality and cognitive function in breast cancer patients after chemotherapy

The goal of this study was to determine the presence or absence of persistent functional impairments in specific brain regions in breast cancer patients during the recovery period after chemotherapy. We calculated degree centrality (DC) and explored the correlation between brain changes and cognitive scores in 29 female patients with breast cancer who had completed chemotherapy within 1-6 years (C + group) and in 28 age-matched patients with breast cancer who did not receive chemotherapy (C- group). All patients underwent rs-fMRI and cognitive testing. Differences in brain functional activity were explored using DC parameters. Correlations between brain features and cognitive scores were analyzed via correlation analysis. Compared with the C- group, the C + group obtained significantly lower motor and cognitive subscores on the Fatigue Scale for Motor and Cognitive Functions and four subscale scores of the Functional Assessment of Cancer Therapy-Cognitive Function (P < 0.05). Furthermore, the C + group exhibited a significantly higher DC z-score (zDC) in the right superior temporal gyrus and left postcentral gyrus (P < 0.01, FWE-corrected), and a lower zDC in the left caudate nucleus (P < 0.01, FWE-corrected). We found a positive correlation between digit symbol test (DST) scores and zDC values in the right superior temporal gyrus (r = 0.709, P < 0.001), and a negative correlation between DST scores and zDC values in the right angular gyrus (r = -0.784, P < 0.001) and left superior parietal gyrus (r = -0.739, P < 0.001). Chemotherapy can cause abnormal brain activity and cognitive decline in patients with breast cancer, and these effects are likely to persist. DC can be used as an imaging marker for chemotherapy-related cognitive impairment after chemotherapy in breast cancer patients.

Early alterations in cortical morphology after neoadjuvant chemotherapy in breast cancer patients: A longitudinal magnetic resonance imaging study

There is growing evidence that chemotherapy may have a significant impact on the brains of breast cancer patients, causing changes in cortical morphology. However, early morphological alterations induced by chemotherapy in breast cancer patients are unclear. To investigate the patterns of those alterations, we compared female breast cancer patients (n = 45) longitudinally before (time point 0, TP0) and after (time point 1, TP1) the first cycle of neoadjuvant chemotherapy, using voxel‐based morphometry (VBM) and surface‐based morphometry (SBM). VBM and SBM alteration data underwent correlation analysis. We also compared cognition‐related neuropsychological tests in the breast cancer patients between TP0 and TP1. Reductions in gray matter volume, cortical thickness, sulcal depth, and gyrification index were found in most brain areas, while increments were found to be mainly concentrated in and around the hippocampus. Reductions of fractal dimension mainly occurred in the limbic and occipital lobes, while increments mainly occurred in the anterior and posterior central gyrus. Significant correlations were found between altered VBM and altered SBM mainly in the bilateral superior frontal gyrus. We found no significant differences in the cognition‐related neuropsychological tests before and after chemotherapy. The altered brain regions are in line with those associated with impaired cognitive domains in previous studies. We conclude that breast cancer patients showed widespread morphological alterations soon after neoadjuvant chemotherapy, despite an absence of cognitive impairments. The affected brain regions may indicate major targets of early brain damage after chemotherapy.

Changes in Brain Functional and Effective Connectivity After Treatment for Breast Cancer and Implications for Intervention Targets

Background: Patients with breast cancer frequently report cognitive impairment both during and after completion of therapy. Evidence suggests that cancer-related cognitive impairments are related to widespread neural network dysfunction. The default mode network (DMN) is a large conserved network that plays a critical role in integrating the functions of various neural systems. Disruption of the network may play a key role in the development of cognitive impairment. Methods: We compared neuroimaging and neurocognitive data from 43 newly diagnosed primary breast cancer patients (mean age = 48, standard deviation [SD] = 8.9 years) and 50 frequency-matched healthy female controls (mean age = 50, SD = 10 years) before treatment and 1 year after treatment completion. Functional and effective connectivity measures of the DMN were obtained using graph theory and Bayesian network analysis methods, respectively. Results: Compared with healthy females, the breast cancer group displayed higher global efficiency and path length post-treatment (p < 0.03, corrected). Breast cancer survivors showed significantly lower performance on measures of verbal memory, attention, and verbal fluency (p < 0.05) at both time points. Within the DMN, local brain network organization, as measured by edge-betweenness centralities, was significantly altered in the breast cancer group compared with controls at both time points (p < 0.0001, corrected), with several connections showing a significant group-by-time effect (p < 0.003, corrected). Effective connectivity demonstrated significantly altered patterns of neuronal coupling in patients with breast cancer (p < 0.05). Significant correlations were seen between hormone blockade therapy, radiation therapy, chemotherapy cycles, memory, and verbal fluency test and edge-betweenness centralities. Discussion: This pattern of altered network organization in the default mode is believed to result in reduced network efficiency and disrupted communication. Subregions of the DMN, the orbital prefrontal cortex and posterior memory network, appear to be at the center of this disruption and this could inform future interventions. Impact statement This prospective study is the first to investigate how post-treatment changes in functional and effective connectivity in the regions of default mode network are related to cancer therapy and measures of memory and verbal learning in breast cancer patients. We demonstrate that the interactions between treatment, brain connectivity, and neurocognitive outcomes coalesce around a subgroup of brain structures in the orbital frontal and parietal lobe. This would suggest that interventions that target these regions may improve neurocognitive outcomes in breast cancer survivors.

Work ability 8 years after breast cancer: exploring the role of social support in a nation-wide survey

INTRODUCTION

As the 5-year survival rate after breast cancer in Norway is 92%, the population of breast cancer survivors (BCSs) is increasing. Knowledge of work ability in this population is scarce. In a population-based cohort of BCSs, we explored work ability 8 years after diagnosis and the association between work ability and social support, and cancer-related variables including late effects and lifestyle factors.

METHODS

In 2019, all Norwegian women < 59 years when diagnosed with stage I-III breast cancer in 2011 or 2012, were identified by the Cancer Registry of Norway and invited to participate in a survey on work life experiences. Work ability was assessed using the Work Ability Index (scale 0-10). Factors associated with excellent work ability (score ≥ 9) were identified using univariate and multivariate logistic regression analyses, and adjusted for socioeconomic-, health- and cancer-related variables.

RESULTS

Of the 1951 eligible BCSs, 1007 (52.8%) responded. After excluding survivors with relapse (n = 1), missing information on work ability score (n = 49), or work status (n = 31), the final sample comprised 926 BCSs within working age at survey (< 67 years). Mean age at survey was 56 years and 8 years (SD 0.7) had passed since diagnosis. Work ability had been reduced from 8.9 (SD 2.3) at diagnosis to 6.3 (SD 3.1). One in three BCSs reported poor work ability (WAS ≤ 5), and seven out of ten reported that their physical work ability had been reduced due to cancer. Social support from colleagues during cancer therapy was associated with excellent work ability, which was not observed for social support provided by supervisors or the general practitioner. Cognitive impairment and fatigue were inversely associated with work ability. None of the cancer-related variables, including treatment, were associated with work ability 8 years after diagnosis.

CONCLUSION

In this population-based sample, one in three BCSs reported poor work ability 8 years after diagnosis. Collegial social support during cancer therapy appears to be a protective factor for sustained work ability, whilst survivors struggling with fatigue and cognitive impairments may represent a particularly vulnerable group for reduced work ability.

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.

Cannabinoid drugs against chemotherapy-induced adverse effects: focus on nausea/vomiting, peripheral neuropathy and chemofog in animal models

Although new drugs are being developed for cancer treatment, classical chemotherapeutic agents are still front-line therapies, despite their frequent association with severe side effects that can hamper their use. Cannabinoids may prevent or palliate some of these side effects. The aim of the present study is to review the basic research which has been conducted evaluating the effects of cannabinoid drugs in the treatment of three important side effects induced by classical chemotherapeutic agents: nausea and vomiting, neuropathic pain and cognitive impairment. Several published studies have demonstrated that cannabinoids are useful in preventing and reducing the nausea, vomits and neuropathy induced by different chemotherapy regimens, though other side effects can occur, such as a reduction of gastrointestinal motility, along with psychotropic effects when using centrally-acting cannabinoids. Thus, peripherally-acting cannabinoids and new pharmacological options are being investigated, such as allosteric or biased agonists. Additionally, due to the increase in the survival of cancer patients, there are emerging data that demonstrate an important cognitive deterioration due to chemotherapy, and because the cannabinoid drugs have a neuroprotective effect, they could be useful in preventing chemotherapy-induced cognitive impairment (as demonstrated through studies in other neurological disorders), but this has not yet been tested. Thus, although cannabinoids seem a promising therapeutic approach in the treatment of different side effects induced by chemotherapeutic agents, future research will be necessary to find pharmacological options with a safer profile. Moreover, a new line of research awaits to be opened to elucidate their possible usefulness in preventing cognitive impairment.

Clemastine Rescues Chemotherapy-Induced Cognitive Impairment by Improving White Matter Integrity

With the improvement of cancer treatment techniques, increasing attention has been given to chemotherapy-induced cognitive impairment through white matter injury. Clemastine fumarate has been shown to enhance white matter integrity in cuprizone- or hypoxia-induced demyelination mouse models. However, whether clemastine can be beneficial for reversing chemotherapy-induced cognitive impairment remains unexplored. In this study, the mice received oral administration of clemastine after chemotherapy. The open-field test and Morris water maze test were used to evaluate their anxiety, locomotor activity and cognitive function. Luxol Fast Blue staining and transmission electron microscopy were used to detect the morphological damage to the myelin. Demyelination and damage to the mature oligodendrocytes and axons were observed by immunofluorescence and western blotting. Clemastine significantly improved their cognitive function and ameliorated white matter injury in the chemotherapy-treated mice. Clemastine enhanced myelination, promoted oligodendrocyte precursor cell differentiation and increased the neurofilament 200 protein levels in the corpus callosum and hippocampus. We concluded that clemastine rescues cognitive function damage caused by chemotherapy through improving white matter integrity. Remyelination, oligodendrocyte differentiation and the increase of neurofilament protein promoted by clemastine are potential strategies for reversing the cognitive dysfunction caused by chemotherapy.

Avaliação de Prejuízo Cognitivo em Sobreviventes de Câncer de Mama: Estudo Transversal

Resumo Estudo prospectivo e transversal, para determinar a prevalência de prejuízo cognitivo decorrente da quimioterapia e explorar fatores preditores e mediadores em sobreviventes de câncer de mama. Utilizou-se o Termômetro de Distress, Escala de Ansiedade e Depressão, Functional Assessment of Chronic Illness Therapy-General e Cognitive Function. As sobreviventes (N = 62) reportaram uma alta prevalência de distress (46,8%) e de ansiedade (24,2%), com baixos escores nas subescalas déficit cognitivo e habilidades cognitivas percebidos. O funcionamento cognitivo esteve associado à idade (β = 1,42; p = 0,002), atuação profissional (β = -23,12; p = 0,004), depressão (β = -5,43; p = 0,001) e qualidade de vida (β = 1,24; p = 0,001). Prejuízo cognitivo deve ser considerado no serviço de Psico-Oncologia.

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.

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.

Memantine Protects against Paclitaxel-Induced Cognitive Impairment through Modulation of Neurogenesis and Inflammation in Mice

Chemotherapy-induced cognitive impairment (CICI) is an adverse side effect of cancer treatment with increasing awareness. Hippocampal damage and related neurocognitive impairment may mediate the development of CICI, in which altered neurogenesis may play a role. In addition, increased inflammation may be related to chemotherapy-induced hippocampal damage. Memantine, an uncompetitive N-methyl-D-aspartate (NMDA) receptor antagonist that may enhance neurogenesis and modulate inflammation, may be useful for treating CICI. To test this hypothesis, paclitaxel was administered to eight-week-old male B6 mice to demonstrate the relationship between CICI and impaired neurogenesis, and then, we evaluated the impact of different memantine regimens on neurogenesis and inflammation in this CICI model. The results demonstrated that both the pretreatment and cotreatment regimens with memantine successfully reversed impaired neurogenesis and spatial memory impairment in behavior tests. The pretreatment regimen unsuccessfully inhibited the expression of peripheral and central TNF-α and IL-1β and did not improve the mood alterations following paclitaxel treatment. However, the cotreatment regimen led to a better modulatory effect on inflammation and restoration of mood disturbance. In conclusion, this study illustrated that impaired neurogenesis is one of the mechanisms of paclitaxel-induced CICI. Memantine may serve as a potential treatment for paclitaxel-induced CICI, but different treatment strategies may lead to variations in the treatment efficacy.

Prospective evaluation of functional brain activity and oxidative damage in breast cancer: changes in task-induced deactivation during a working memory task

Cancer-related cognitive dysfunction is an important issue for breast cancer survivors. Previous research has identified both cross-sectional and longitudinal alterations in brain function related to cancer status and treatment. In this study, we prospectively collected functional magnetic resonance imaging data in breast cancer cases treated with adjuvant chemotherapy and in controls with no cancer history during a working memory task. Data and blood specimens were collected immediately prior to the start of treatment (baseline) and following completion of treatment (follow-up), and at yoked intervals for controls. In secondary analysis we assessed the levels of oxidative DNA damage in peripheral blood lymphocytes of cases and controls using the Comet assay. A significant group*time interaction revealed reduced deactivation in the superior frontal gyrus in the controls at follow-up, in contrast to cases, who exhibited similar magnitude of deactivation at baseline and follow-up. Working memory performance indicated a significant improvement in the controls at follow-up, and no change in performance in cases. In secondary analyses, oxidative DNA damage levels were elevated in the cases at follow-up compared to controls, but no associations were found between the Comet assay variables and functional imaging at either time-point or group. In light of previous reports on task induced deactivations, our findings reflect continuing effortful processing at follow-up in the breast cancer group, with relatively less effortful processing in the control group given the reduced novelty and practice effects from the baseline to follow-up.

Pharmacological rescue of cognitive function in a mouse model of chemobrain

BACKGROUND

After chemotherapy, many cancer survivors suffer from long-lasting cognitive impairment, colloquially known as "chemobrain." However, the trajectories of cognitive changes and the underlying mechanisms remain unclear. We previously established paclitaxel-induced inositol trisphosphate receptor (InsP3R)-dependent calcium oscillations as a mechanism for peripheral neuropathy, which was prevented by lithium pretreatment. Here, we investigated if a similar mechanism also underlay paclitaxel-induced chemobrain.

METHOD

Mice were injected with 4 doses of 20 mg/kg paclitaxel every other day to induced cognitive impairment. Memory acquisition was assessed with the displaced object recognition test. The morphology of neurons in the prefrontal cortex and the hippocampus was analyzed using Golgi-Cox staining, followed by Sholl analyses. Changes in protein expression were measured by Western blot.

RESULTS

Mice receiving paclitaxel showed impaired short-term spatial memory acquisition both acutely 5 days post injection and chronically 23 days post injection. Dendritic length and complexity were reduced in the hippocampus and the prefrontal cortex after paclitaxel injection. Concurrently, the expression of protein kinase C α (PKCα), an effector in the InsP3R pathway, was increased. Treatment with lithium before or shortly after paclitaxel injection rescued the behavioral, cellular, and molecular deficits observed. Similarly, memory and morphological deficits could be rescued by pretreatment with chelerythrine, a PKC inhibitor.

CONCLUSION

We establish the InsP3R calcium pathway and impaired neuronal morphology as mechanisms for paclitaxel-induced cognitive impairment. Our findings suggest lithium and PKC inhibitors as candidate agents for preventing chemotherapy-induced cognitive impairment.

The Promise of Nutrient-Derived Bioactive Compounds and Dietary Components to Ameliorate Symptoms of Chemotherapy-Related Cognitive Impairment in Breast Cancer Survivors

OPINION STATEMENT

One of the most burdensome symptoms reported by breast cancer patients is chemotherapy-related neurocognitive impairment. It is estimated that of the 11 million cancer survivors in the USA, 22% of them are breast cancer patients. The National Cancer Institute classified chemotherapy-related cognitive impairment (CRCI) as one of the most debilitating sequelae of cancer therapy, limiting this patient population from recommencing their lives prior to the diagnosis of breast cancer. Currently, there are no strategies that are established to prevent, mitigate, or treat CRCI. In addition to surviving cancer, quality of life is critical to cancer survivors. Based on the multiple and complex biological and psychosocial etiology, the varying manifestation and extent of cognitive decline documented in breast cancer survivors, possibly attributed to varying combinations of chemotherapy and dose and duration of therapy, multimodal interventions combining promising nutrient-derived bioactive compounds with antioxidant and anti-inflammatory properties, in addition to structured cognitive training and exercise regimens, can work synergistically to reduce inflammation and oxidative stress with significant improvement in cognitive function resulting in improvements in quality of life of breast cancer survivors.

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

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

Prevalence of cognitive impairment and change in patients with breast cancer: A systematic review of longitudinal studies

OBJECTIVE

Patients with breast cancer face cognitive impairment that affects their quality of life; partially attributable to treatment. Our aim was to detail the prevalence and change of cognitive impairment during the course of treatment. We also investigated the effect of therapy (chemotherapy [CT]) vs. radiotherapy and/or endocrine therapy vs. healthy controls).

METHODS

This article reviews longitudinal cohort studies published to date in Medline and Embase that (i) assess cognition before and after therapy, (ii) report prevalence cognitive impairment or change, and (iii) use standardized and valid neuropsychological tests. We used the original authors' criteria for cognitive impairment.

RESULTS

The title and abstract of 891 articles were screened, resulting in the identification of 90 potentially relevant articles while applying the eligibility criteria. After full-text examination, 17 studies were included. Prevalence of cognitive impairment range from 25% before therapy, through 24% after therapy to 21% at maximal 1-year follow-up (FU). Compared to their pretreatment cognitive functioning, 24% of patients decline after treatment and 24% at 1-year FU. Some studies also reported cognitive improvement showing that 15% and 31% of patients improve, respectively. In general, patients undergoing CT have a higher chance of cognitive impairment and decline than no-CT patients and healthy controls.

CONCLUSIONS

This study shows that one out of four breast cancer patients shows cognitive impairment prior to treatment administration CT and a significant number of patients decline during the course of disease, suggesting that cognitive impairment is not exclusively related to CT and/or no-CT therapies. This study shows that assessment of cognitive functioning, ideally over time, is crucial and may help the implementation of personalized rehabilitation pathways.

Chemotherapy-induced grey matter abnormalities in cancer survivors: a voxel-wise neuroimaging meta-analysis

BACKGROUND

Findings regarding chemotherapy-induced grey matter abnormalities are heterogeneous, and no meta-analysis has quantitatively assessed brain structural alterations in cancer survivors treated with chemotherapy.

PURPOSE

To investigate the grey matter abnormalities in non-CNS (central nervous system) cancer survivors treated with chemotherapy using Anisotropic Effect Size Signed Differential Mapping (AES-SDM) software.

METHOD

We identified studies published up to Sep 2018 that compared grey matter in non-CNS cancer survivors treated with chemotherapy (CT+, 10 data sets including 433 individuals) and cancer survivors not treated with chemotherapy (CT-, 7 data sets including 210 individuals) or healthy controls (HC, 3 data sets including 407 individuals) using whole-brain VBM. We used statistical maps from the studies included where available and reported peak coordinates otherwise.

RESULTS

Compared with both CT- and HC, the CT + groups exhibited a reduced grey matter volume (GMV), mainly in the prefrontal and anterior cingulate cortex (ACC) and right fusiform gyrus (FG). A smaller GMV in the FG and prefrontal cortex were found in the CT + compared with the CT-groups and in the CT + groups with impaired cognition. GMV in two areas was positively associated with the time since chemotherapy.

CONCLUSIONS

The present results suggest that non-CNS cancer survivors treated with chemotherapy exhibit grey matter abnormalities in the brain, especially in the prefrontal and ACC cortex. Grey matter volume changes after chemotherapy may contribute to cognitive impairments in cancer survivors that can be observed after chemotherapy.

Internet-based cognitive rehabilitation for WORking Cancer survivors (i-WORC): study protocol of a randomized controlled trial

Background

Cognitive problems are common in non-central nervous system cancer survivors. These problems are perceived as an important contributor to decline in work performance and work ability. Various interventions for cognitive problems have been proposed, but effectiveness regarding work-related outcomes has not yet been established. Effective treatment options to alleviate the adverse influence of cognitive problems on work performance are needed for working cancer survivors. In this paper, we will describe the design of a randomized, controlled, multicenter trial that evaluates the (cost-)effectiveness of an Internet-based cognitive rehabilitation program for occupationally active cancer survivors confronted with cognitive problems.

Methods/ design

A three-armed randomized controlled trial will be conducted, including two intervention groups (i.e., basic and extensive cognitive rehabilitation program) and one waitlist control group. In total, 261 cancer survivors (18–65 years) who have returned to work and who experience cognitive problems will be recruited. Patients with and without cognitive impairment as established in a neuropsychological assessment will be eligible; stratification will take place based on the presence of this cognitive impairment. The extensive intervention arm will contain a comprehensive training program (including psycho-education, fatigue management, and cognitive strategy training) with individual guidance (blended intervention). The basic intervention arm will contain a brief cognitive training program (including psycho-education and fatigue management) without individual guidance. The primary outcome will be accomplishment of an individually defined work-related treatment goal. Secondary outcomes include, among others, subjective cognitive functioning, work functioning, and quality of life. Primary and secondary outcomes will be measured at baseline (T0) and at 12 weeks (T1) and 26 weeks (T2) post-randomization.

Discussion

About 40–50% of the cancer patients worldwide are of working age at time of diagnosis. Many of the occupationally active cancer survivors experience cognitive problems. Both from an individual and a societal perspective, it is important to sustain cancer survivors’ employability. An effective treatment to alleviate the impact of cognitive decline and to improve work ability might help cancer survivors to sustain employability.

Trial registration

ClinicalTrials.gov NCT03900806. Registered on 03 April 2019 (current status: ongoing).

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

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

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

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

Cellular mechanisms and treatments for chemobrain: insight from aging and neurodegenerative diseases

Chemotherapy is a life-saving treatment for cancer patients, but also causes long-term cognitive impairment, or "chemobrain", in survivors. However, several challenges, including imprecise diagnosis criteria, multiple confounding factors, and unclear and heterogeneous molecular mechanisms, impede effective investigation of preventions and treatments for chemobrain. With the rapid increase in the number of cancer survivors, chemobrain is an urgent but unmet clinical need. Here, we leverage the extensive knowledge in various fields of neuroscience to gain insights into the mechanisms for chemobrain. We start by outlining why the post-mitotic adult brain is particularly vulnerable to chemotherapy. Next, through drawing comparisons with normal aging, Alzheimer's disease, and traumatic brain injury, we identify universal cellular mechanisms that may underlie the cognitive deficits in chemobrain. We further identify existing neurological drugs targeting these cellular mechanisms that can be repurposed as treatments for chemobrain, some of which were already shown to be effective in animal models. Finally, we briefly describe future steps to further advance our understanding of chemobrain and facilitate the development of effective preventions and treatments.

Abrogating doxorubicin-induced chemobrain by immunomodulators IFN-beta 1a or infliximab: Insights to neuroimmune mechanistic hallmarks

Chemobrain is a well-established clinical syndrome that impairs patient's daily function, in particular attentiveness, coordination and multi-tasking. Thus, it interferes with patient's quality of life. The putative pharmacological intervention against chemobrain relies on understanding the molecular mechanisms underlying it. This study aimed to examine the potential neuroprotective effects of two immunomodulators: Interferon-β-1a (IFN-β-1a), as well as Tumor necrosis function-alpha (TNF-α) inhibitor; Infliximab in doxorubicin (DOX)-induced chemobrain in rats. Besides, the current study targets investigating the possible molecular mechanisms in terms of neuromodulation and interference with different death routes controlling neural homeostasis. Herein, the two immunomodulators IFN-β-1a at a dose of 300,000 units; s.c.three times per week, or Infliximab at a dose of 5 mg/kg/week; i.p. once per week were examined against DOX (2 mg/kg/w, i.p.) once per week for 4 consecutive weeks in rats.The consequent behavioral tests and markers for cognitive impairment, oxidative stress, neuroinflammation, apoptosis and neurobiological abnormalities were further evaluated. Briefly, IFN-β-1a or Infliximab significantly protected against DOX-induced chemobrain. IFN-β-1a or Infliximab ameliorated DOX-induced hippocampal histopathological neurodegenerative changes, halted DOX-induced cognitive impairment, abrogated DOX-induced mitochondrial oxidative, inflammatory and apoptotic stress, mitigated DOX-induced autophagic dysfunction and finally upregulated the mitophagic machineries. In conclusion, these findings suggest that either IFN-β-1a or Infliximab offers neuroprotection against DOX-induced chemobrain which could be explained by their antioxidant, anti-inflammatory, pro-autophagic, pro-mitophagic and antiapoptotic effects. Future clinical studies are recommended to personalize either use of IFN-β-1a or infliximab to ameliorate DOX-induced chemobrain.

Episodic memory for visual scenes suggests compensatory brain activity in breast cancer patients: a prospective longitudinal fMRI study

It has been hypothesized that breast cancer and its chemotherapy can impart functional neural changes via an overlap with biological mechanisms associated with aging. Here we used fMRI to assess whether changes in neural activity accompanying visual episodic memory encoding and retrieval suggest altered activations according to patterns seen in functional imaging of cognitive aging. In a prospective longitudinal design, breast cancer patients (n = 13) were scanned during memory encoding and retrieval before and after chemotherapy treatment, and compared to healthy-age matched controls (n = 13). Our results indicate that despite equivalent behavioral performance, encoding and retrieval resulted in increased activation of prefrontal regions for the breast cancer group compared to controls for both before and after chemotherapy treatment. This was accompanied by decreased activity in posterior brain regions after chemotherapy, particularly those involved in visual processing, for the breast cancer group compared to controls. These findings are discussed as evidence for a possible anterior shift in neural processing to compensate for deficiencies in posterior brain regions, consistent with an accelerated aging account. Cancer and chemotherapy can impact brain regions underlying episodic memory, leading to additional recruitment of control regions, which may be linked to mechanisms related to aging.

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

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

Impact of transcranial direct current stimulation on sustained attention in breast cancer survivors: Evidence for feasibility, tolerability, and initial efficacy

BACKGROUND

A significant subset of breast cancer survivors experience cognitive difficulties in attention and memory, which persist for years following treatment. Transcranial direct current stimulation (tDCS) has been shown to be effective in improving working memory, attention, processing speed, and other cognitive functions in both healthy and clinical populations. To date, no studies have examined tDCS for rehabilitation of cancer-related cognitive dysfunction.

OBJECTIVE/HYPOTHESIS

We aimed to provide preliminary evidence for feasibility, tolerability, acceptability, and efficacy of tDCS in improving performance on a measure of sustained attention.

METHODS

In a within-subjects design, 16 breast cancer survivors underwent 2 consecutive days of active tDCS over the prefrontal cortex, and 2 days of sham tDCS, counterbalanced for order of stimulation condition, while performing a continuous performance test.

RESULTS

Stimulation was feasible and tolerable, with 89% of participants completing all sessions, and none reporting more than mild to moderate discomfort. Analyses of efficacy showed that during active stimulation, participants had significantly lower standard errors of reaction times overall, indicating better sustained attention ability, as compared to sham stimulation (p < 0.05). Furthermore, the effect of stimulation on standard errors of reaction times differed by inter-stimulus interval (ISI): for 1 and 2 s ISIs, there was no significant difference in performance between sham and active tDCS conditions, but for 4 s ISIs, stimulation improved variability in response times relative to sham (p < 0.05).

CONCLUSIONS

Results suggest that tDCS is feasible, tolerable, and may be an effective intervention to improve sustained attention difficulties in survivors with cancer-related cognitive dysfunction.

Cancer-related cognitive problems at work: experiences of survivors and professionals

PURPOSE

Cancer-related cognitive problems (cancer-related cognitive problems) in working cancer survivors are found to affect work outcomes. We aimed to generate in-depth information regarding cancer-related cognitive problems in working cancer survivors, strategies used to cope with cancer-related cognitive problems at work, and needs of cancer survivors and professionals regarding cancer-related cognitive problems at work.

METHODS

Five focus groups were formed, amongst which three focus groups with cancer survivors (n = 8, n = 7, and n = 8) and two focus groups with professionals (n = 7, n = 8). Thematic analysis of the transcripts was performed to create concepts.

RESULTS

Both cancer survivors and professionals confirmed that cancer-related cognitive problems, which occurred in several domains of neurocognitive functioning, affect work functioning. Cancer survivors used several strategies (e.g., applying practical adjustments, re-organization of work, and accepting limitations) to cope with cancer-related cognitive problems at work, as did professionals in their attempt at supporting cancer survivors facing these problems. Various needs of cancer survivors (e.g., supportive care options, acknowledgment by others) and professionals (e.g., improvement of expertise, clarity about referral pathways) regarding cancer-related cognitive problems at work were mentioned.

CONCLUSIONS

Due to the growing number of working cancer survivors dealing with cancer-related cognitive problems, it is essential to sustain their employability. Therefore, cognitive rehabilitation interventions should be developed, taking functioning at work into account. Knowledge amongst professionals regarding cancer-related cognitive problems, as well as coordination of care for cancer-related cognitive problems, should be improved. Ensuring professional education regarding cancer-related cognitive problems, within both the healthcare and occupational setting, is of utmost importance.

IMPLICATIONS FOR CANCER SURVIVORS

Support for working cancer survivors who experience cancer-related cognitive problems might increase their employability in the longer term.

Post-chemotherapy cognitive impairment in hematological patients: current understanding of chemobrain in hematology

Introduction: Cognitive impairment caused by chemotherapies, a condition known as chemobrain, is a possible side effect that affects alertness, learning, memory, and concentration.Areas covered: Chemobrain has been principally investigated as a possible side-effect among cancer patients. However, numerous drugs used to treat hematological malignancies can determine the appearance of chemobrain. In this review, we have examined some commonly used drugs for the treatment of hematological malignancies which are known to have a deleterious action on cognitive functions.Numerous mechanisms have been suggested, comprising the direct neurotoxicity of chemotherapeutic drugs, oxidative stress, genetic predisposition, cytokine-provoked damage, histone modifications, immune alteration, and the action of chemotherapeutic on trophic factors and structural proteins of brain cells.Expert commentary: Cognitive dysfunction provoked by the treatment of hematological diseases is an actual challenge in clinical practice. Actually, there are no totally efficient and innocuous treatments for this syndrome. It is important that further investigations specify the existence of predictors and gravity factors to pre- and post-therapy cognitive change and identify the influence of tumor treatments on the cognitive alterations in long-term, cancer survivors. Moreover, future studies are needed to analyze the interactions between genetic risk, amyloid accumulation, intrinsic brain networks, and chemotherapy.