Cognitive functioning in breast cancer survivors: a controlled comparison

Cognitive function and breast cancer molecular subtype before and after chemotherapy

Chemotherapy-related cognitive impairment has been reported in patients with breast cancer and received growing attention due to increased survival rate. However, cognitive outcome according to pathological tumor features, especially human epidermal growth factor receptor (HER2) status, has not been clearly elucidated. Despite its potential link with cognitive status through neuroinflammatory response, existing research is sparse and limited to cross-sectional studies. In this observational cohort study, 52 breast cancer patients received a series of neuropsychological examinations before and after chemotherapy. Patients' performances were compared with normative data, and analyzed with Reliable Change Indices and mixed-model analysis of covariance. Results showed that there was a higher percentage of HER2+ patients than HER2- patients who showed defective attention and processing speed before chemotherapy, and that there were more patients with HER2+ status showing cognitive decline on tests of attention and executive functions following chemotherapy. Group-wise analyses confirmed the foregoing pattern and further revealed that patients with HER2+ status also tended to deteriorate more in verbal memory after chemotherapy. These findings indicate that HER2 overexpression may serve as prognostic factors that help explain the heterogeneous cognitive outcome in breast cancer survivors. Further studies are needed to replicate this finding and delineate the underlying mechanisms.

Efficacy of Mindfulness-Based Stress Reduction for Breast Cancer (MBSR(BC)) a Treatment for Cancer-related Cognitive Impairment (CRCI): A Randomized Controlled Trial

Introduction: The Mindfulness-Based Stress Reduction (MBSR) Program for breast cancer survivors (BCS) is designed to enhance cognitive training through formal and informal meditational practices. This randomized clinical trial (RCT) aimed to evaluate if BCS assigned to either the MBSR(BC), Breast Cancer Education Support (BCES), or Usual Care (UC) regimens experienced greater improvements at 6, 12, and 26 weeks on objective and subjective cognitive performance. Methods: BCS (n = 212) randomized to a three-group RCT: MBSR(BC) (n = 91), BCES (n = 90), or UC (n = 31) were assessed on cognitive performance and symptoms at baseline, 6, 12, and 26 weeks. Linear mixed models were fit to evaluate the effects of the MBSR(BC) program, hypothesizing ordered effect improvements: (MBSR[BC] highest, BCES intermediate, UC lowest) along with baseline characteristics evaluated as moderators. Results: Of the BCS (mean age of 57), 73% were White, and non-Hispanic, and 77% received both chemotherapy (CT) and radiation. Cognitive performance improved in all groups. Although there were no statistically significant between-group differences in cognitive outcomes, significant symptom reductions occurred for the MBSR(BC) group (p = 0.003). Within-group effect size analysis at 26 weeks showed substantial improvements in all three groups (effect sizes >0.50) in subjective impairments and quality of life (effect size >0.50) and objective measures of cognitive performance. MBSR(BC) showed the largest within-group effect size in the reduction of fatigue (effect size = 0.81). Effect sizes occurred in the hypothesized direction for 10 of the 18 outcomes. Discussion: Although the MBSR(BC) program did not show significant differences in cognitive performance compared with BCES and UC, all groups improved and reductions in fatigue were beneficial for MBSR(BC). Results suggest that cognitive performance may improve after CT over time considering one's natural history. Furthermore, BCS enrolled in RCTs may be more motivated to improve their health status (NCT02786797).

Longitudinal Neuropathological Consequences of Extracranial Radiation Therapy in Mice

Cancer-related cognitive impairment (CRCI) is a consequence of chemotherapy and extracranial radiation therapy (ECRT). Our prior work demonstrated gliosis in the brain following ECRT in SKH1 mice. The signals that induce gliosis were unclear. Right hindlimb skin from SKH1 mice was treated with 20 Gy or 30 Gy to induce subclinical or clinical dermatitis, respectively. Mice were euthanized at 6 h, 24 h, 5 days, 12 days, and 25 days post irradiation, and the brain, thoracic spinal cord, and skin were collected. The brains were harvested for spatial proteomics, immunohistochemistry, Nanostring nCounter® glial profiling, and neuroinflammation gene panels. The thoracic spinal cords were evaluated by immunohistochemistry. Radiation injury to the skin was evaluated by histology. The genes associated with neurotransmission, glial cell activation, innate immune signaling, cell signal transduction, and cancer were differentially expressed in the brains from mice treated with ECRT compared to the controls. Dose-dependent increases in neuroinflammatory-associated and neurodegenerative-disease-associated proteins were measured in the brains from ECRT-treated mice. Histologic changes in the ECRT-treated mice included acute dermatitis within the irradiated skin of the hindlimb and astrocyte activation within the thoracic spinal cord. Collectively, these findings highlight indirect neuronal transmission and glial cell activation in the pathogenesis of ECRT-related CRCI, providing possible signaling pathways for mitigation strategies.

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.

Association of Longitudinal Changes in Cerebral Microstructure with Cognitive Functioning in Breast Cancer Survivors after Adjuvant Chemotherapy

Background: Adjuvant chemotherapy for breast cancer might impact cognitive function and brain structure. Methods: In this study, we investigated the cerebral microstructural changes in breast cancer survivors after adjuvant chemotherapy and the correlation with cognitive function with both cross-sectional and longitudinal study designs. All participants underwent structural MRI. In total, we recruited 67 prechemotherapy patients (BB), 67 postchemotherapy patients (BA), and 77 healthy controls (BH). For the follow-up study, 28 participants in the BH and 28 in the BB groups returned for imaging and assessment (BHF, BBF). Voxel-based morphometry analysis was performed to evaluate differences in brain volume; vertex-based shape analysis was used to assess the shape alterations of subcortical regions. Moreover, multiple regression was applied to assess the association between the changes in neuropsychological assessment and brain volume. Results: The results showed brain volume reduction in the temporal and parietal gyrus in BB and BA patients. Among each group, we also found significant shape alterations in the caudate and thalamus. Volume reductions in the temporal regions and shape changes in the caudate and hippocampus were also observed in patients from time point 1 to time point 2 (postchemotherapy). An association between brain volume and cognitive performance was also found in the limbic system. Conclusions: Based on our findings, we can provide a better understanding of the cerebral structural changes in breast cancer survivors, establish a subsequent prediction model, and serve as a reference for subsequent treatment.

Use of focused computerized cognitive training (Neuroflex) to improve symptoms in women with persistent chemotherapy-related cognitive impairment

Purpose

Chemotherapy-related cognitive impairment (CRCI) is a distressing and increasingly recognized long-term sequela reported by breast cancer patients following cancer treatment. There is an urgent but unmet clinical need for treatments that improve CRCI. In this context, we proposed the use of a novel cognitive enhancement strategy called Neuroflex to target CRCI experienced by breast cancer survivors.

Methods

The primary aim of this pilot study was to evaluate the feasibility and acceptability of Neuroflex, a novel digital cognitive enhancement strategy, in breast and gynecologic cancer survivors with CRCI. Secondary analyses focused on whether improvements in performance on Neuroflex were associated with improvement in subjective cognitive complaints and objective cognitive performance measures.

Results

Participants (N = 21) completed an average of 7.42 hours of Neuroflex training per week, an average of 44.5 (±1.01) hours total, and had a 100% completion rate. Participants exhibited significant improvement in self-reported cognitive function as well as significant improvement on tasks of verbal learning and memory and auditory working memory. Participants also exhibited improvement in mood, as well as improvement on a disability assessment.

Conclusions

Results demonstrate feasibility and that breast cancer survivors are capable of completing a lengthy and challenging cognitive training program. Secondly, Neuroflex may confer specific cognitive benefits to both self-reported and objective performance. Results strongly support further investigation of Neuroflex in a larger controlled trial to establish efficacy for CRCI symptoms. Further studies may also result in optimization of this digital intervention for women with CRCI.

Association of fall rate and functional status by APOE genotype in cancer survivors after exercise intervention

PURPOSE/OBJECTIVES

Cancer treatment survivors often report impaired functioning and increased falls. Not all survivors experience the same symptom burden, suggesting individual susceptibilities. APOE genotype is a potential genetic risk factor for cancer treatment related side effects. Lifestyle factors such as physical activity can mitigate the effect of APOE genotype on measures of clinical interest in individuals without a history of cancer. We tested the hypothesis that APOE genotype influences cancer treatment related side effects and symptoms as well as response to exercise intervention.

MATERIALS AND METHODS

Data from a subsample of a study of fall prevention exercise in post-treatment female cancer survivors aged 50-75 years old (https://clinicaltrials.gov NCT01635413) were used to conduct a secondary data analysis. ApoE genotype was determined by serum sampling. Physical functioning, frequency of falls, and symptom burden were assessed using survey instruments.

RESULTS

Data from 126 female cancer survivors a median of 49 months out from cancer diagnosis were analyzed. ApoE4 carriers trended toward a higher fall rate at baseline (p = 0.059), but after exercise intervention had a fall rate lower than E4 non-carriers both immediately after structured intervention (p = 0.013) and after 6 months of follow up (p = 0.002). E2 carriers did not show improved measures of depressive symptoms and self-report disability after exercise intervention. E3 homozygotes showed increased self report physical activity after the 6 month exercise intervention, but E4 and E2 carriers did not.

CONCLUSIONS

APOE genotype may modulate cancer treatment related side effects and symptoms and response to exercise intervention.

Relationship between World Assumptions and Post-Traumatic Growth among Polish Cancer Patients: Moderating Effect of Rumination

BACKGROUND

Although post-traumatic growth is believed to be the result of complex interplays between various factors, cognitive variables appear to play a special role in these interactions. Yet, research on this topic is scant. Therefore, the first purpose of this study was to verify whether there is a direct relationship between world assumptions and post-traumatic growth among Polish cancer patients. As the effect of psychological change in post-traumatic growth may be affected by basic beliefs about the world and oneself, the second goal was to assess whether this association is moderated by rumination.

METHODS

The study included 215 Polish cancer patients. The Post-traumatic Growth and Depreciation Inventory-Expanded version-(intrusive and deliberate rumination), the World Assumption Scale, and the Event-related Rumination Inventory were applied.

RESULTS

Positive, albeit weak, correlations were found between the dimensions of world assumptions and post-traumatic growth. Post-traumatic growth correlated negatively with intrusive rumination and positively with deliberate rumination. The outcomes show that the level of post-traumatic growth resulting from world assumptions is significantly different at various levels of intrusive and deliberate rumination.

CONCLUSION

Lower/medium intrusive rumination seems to strengthen the relationship between benevolence of the world/worthiness of the self and post-traumatic growth, and higher deliberate rumination tends to reinforce the relationship between meaningfulness and post-traumatic growth.

Change in Neurocognitive Performance Among Patients with Non-Hodgkin Lymphoma in the First Year after Chimeric Antigen Receptor T Cell Therapy

The success of chimeric antigen receptor (CAR) T cell therapy in treating patients with relapsed/refractory hematologic malignancies is leading to a growing number of survivors treated with this regimen. To our knowledge, no previous studies have examined neurocognitive performance in adult CAR T cell therapy recipients, despite high rates of neurotoxicity and cytokine release syndrome (CRS) in the acute treatment period. This study examined changes in neurocognitive performance in the first year after CAR T cell therapy for non-Hodgkin lymphoma (NHL). Putative risk factors for worsening neurocognitive performance (eg, neurotoxicity, CRS) were explored as well. Neurocognition was assessed before initiation of CAR T cell therapy and at 30, 90, and 360 days post-treatment. Clinical variables were abstracted from medical records. Mixed models were used to examine change in total neurocognitive performance (TNP) and cognitive domains (ie, attention, executive function, verbal ability, immediate and delayed memory, and visuospatial abilities). Among 117 participants (mean age, 61 years; 62% male), TNP and executive function declined slightly on average from baseline to day 90 and then improved from day 90 to day 360 (P < .04). Small but significant linear declines in visuospatial ability on average were also observed over time (P = .03). Patients who had 4 or more lines of previous therapy and those with worse neurotoxicity (but not CRS) demonstrated worse TNP. CAR T cell therapy recipients reported transient or persistent deterioration in several cognitive domains, although changes were slight. These findings may be useful when educating future patients on what to expect when receiving CAR T cell therapy.

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

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

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.

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.

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.

Implementation of a Brief Screening Tool to Identify Needs of Breast Cancer Survivors

BACKGROUND

Innovation in health care delivery is needed to improve care for cancer survivors. We report our experience with adapting screening questions from the National Comprehensive Cancer Network (NCCN) guideline to evaluate the needs of breast cancer survivors.

MATERIALS AND METHODS

We adapted the NCCN-recommended screening questions into a plain language, self-administered 1-page intake questionnaire. The tool was administered to a convenience sample of female breast cancer survivors at follow-up oncology and primary care visits. Domains included symptoms, lifestyle concerns, and financial issues. Frequency of concerns was assessed as "never," "rarely," "sometimes," "very frequently," and "always." We evaluated feasibility and utility of administration and the prevalence and frequency of patient-reported concerns.

RESULTS

The questionnaire was highly acceptable to patients and enhanced visits for clinicians. Clinicians reported that it led to discussion of issues that may not otherwise be addressed in the visit and did not find it burdensome. The most commonly endorsed patient concerns were desire to improve fitness or nutrition, worry about cancer recurrence, and insomnia. A majority also reported feeling anxiety and aches or pains in joints or extremities. Several issues known to be underreported in clinic visits were frequently endorsed, included sexual dissatisfaction and memory impairments. Clinicians suggested incorporating the tool into the electronic health record to increase utility and awareness.

CONCLUSION

Screening for individual needs among breast cancer survivors is feasible, efficient, and may identify prevalent issues that otherwise can be missed in routine survivorship care.

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

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

Capacity to consent to research participation in adults with metastatic cancer: comparisons of brain metastasis, non-CNS metastasis, and healthy controls

Background

To evaluate the ability of individuals with metastatic cancer to provide informed consent to research participation, we used a structured vignette-based interview to measure 4 consenting standards across 3 participant groups.

Methods

Participants included 61 individuals diagnosed with brain metastasis, 41 individuals diagnosed with non-CNS metastasis, and 17 cognitively intact healthy controls. All groups were evaluated using the Capacity to Consent to Research Instrument (CCRI), a performance-based measure of research consent capacity. The ability to provide informed consent to participate in research was evaluated across 4 consent standards: expressing choice, appreciation, reasoning, and understanding. Capacity performance ratings (intact, mild/moderate impairment, severe impairment) were identified based on control group performance.

Results

Results revealed that the brain metastasis group performed significantly lower than healthy controls on the consent standard of understanding, while both metastatic cancer groups performed below controls on the consent standard of reasoning. Both metastatic cancer groups performed similar to controls on the standards of appreciation and expressing choice. Approximately 60% of the brain metastasis group, 54% of the non-CNS metastasis group, and 18% of healthy controls showed impaired research consent capacity.

Conclusions

Our findings, using a performance-based assessment, are consistent with other research indicating that the research consent process may be overly cumbersome and confusing. This, in turn, may lead to research consent impairment not only in patient groups but also in some healthy adults with intact cognitive ability.

Risks of cognitive detriments after low dose heavy ion and proton exposures

Purpose: Heavy ion and proton brain irradiations occur during space travel and in Hadron therapy for cancer. Heavy ions produce distinct patterns of energy deposition in neuron cells and brain tissues compared to X-rays leading to large uncertainties in risk estimates. We make a critical review of findings from research studies over the last 25 years for understanding risks at low dose. Conclusions: A large number of mouse and rat cognitive testing measures have been reported for a variety of particle species and energies for acute doses. However, tissue reactions occur above dose thresholds and very few studies were performed at the heavy ion doses to be encountered on space missions (<0.04 Gy/y) or considered dose-rate effects, such that threshold doses are not known in rodent models. Investigations of possible mechanisms for cognitive changes have been limited by experimental design with largely group specific and not subject specific findings reported. Persistent oxidative stress and activated microglia cells are common mechanisms studied, while impairment of neurogenesis, detriments in neuron morphology, and changes to gene and protein expression were each found to be important in specific studies. Future research should focus on estimating threshold doses carried out with experimental designs aimed at understating causative mechanisms, which will be essential for extrapolating rodent findings to humans and chronic radiation scenarios, while establishing if mitigation are needed.

DETRIMENTS IN NEURON MORPHOLOGY FOLLOWING HEAVY ION IRRADIATION: WHAT'S THE TARGET?

Neuron cells consist of the soma or cell body, axons, dendritic arbor with multiple branches, and dendritic spines which are the substrates for memory storage and synaptic transmission. Detriments in neuron morphology are suggested to play a key role in cognitive impairments following brain irradiation. Multiple molecular mechanisms are involved in the regulation and stability of neuron morphology, while the effects of radiation on these processes have not been studied extensively. In this report, we consider possible biological targets in neurons for energy deposition (ED) by charged particles that could lead to neuron morphology detriments, and the resulting dose and radiation quality dependence of such detriments. The track structures of heavy ions including high charge and energy (HZE) particles consists of core of high-ED events and a penumbra of sparse ED from δ-ray electrons produced in ionization of target molecules. We consider the role of track structure relative to possible targets causative in the degradation of morphology.

International Cognition and Cancer Task Force Recommendations for Neuroimaging Methods in the Study of Cognitive Impairment in Non-CNS Cancer Patients

Cancer- and treatment-related cognitive changes have been a focus of increasing research since the early 1980s, with meta-analyses demonstrating poorer performance in cancer patients in cognitive domains including executive functions, processing speed, and memory. To facilitate collaborative efforts, in 2011 the International Cognition and Cancer Task Force (ICCTF) published consensus recommendations for core neuropsychological tests for studies of cancer populations. Over the past decade, studies have used neuroimaging techniques, including structural and functional magnetic resonance imaging (fMRI) and positron emission tomography, to examine the underlying brain basis for cancer- and treatment-related cognitive declines. As yet, however, there have been no consensus recommendations to guide researchers new to this field or to promote the ability to combine data sets. We first discuss important methodological issues with regard to neuroimaging study design, scanner considerations, and sequence selection, focusing on concerns relevant to cancer populations. We propose a minimum recommended set of sequences, including a high-resolution T1-weighted volume and a resting state fMRI scan. Additional advanced imaging sequences are discussed for consideration when feasible, including task-based fMRI and diffusion tensor imaging. Important image data processing and analytic considerations are also reviewed. These recommendations are offered to facilitate increased use of neuroimaging in studies of cancer- and treatment-related cognitive dysfunction. They are not intended to discourage investigator-initiated efforts to develop cutting-edge techniques, which will be helpful in advancing the state of the knowledge. Use of common imaging protocols will facilitate multicenter and data-pooling initiatives, which are needed to address critical mechanistic research questions.

Association of functional dorsal attention network alterations with breast cancer and chemotherapy

Breast cancer is the most common cancer among women worldwide. Adjuvant chemotherapy has significantly reduced mortality but increased cognitive impairments, including attention function, making quality of life issues a crucial concern. This study enrolled nineteen breast cancer patients who were treated with standard chemotherapy within 6 months and 20 sex-matched healthy controls to investigate the brain effects of chemotherapy. All participants underwent resting-state functional magnetic resonance imaging (rs-fMRI) with mean fractional amplitude of low-frequency fluctuation (mfALFF) analysis and were correlated with neuropsychological tests, including the Mini-Mental State Examination (MMSE), the Cognitive and Affective Mindfulness Scale-Revised (CAMS-R), and the Impact of Event Scale-Revised (IES-R), to explore the possible underlying mechanism of cognitive alternations. We found increased mfALFF over the frontoparietal lobe and decreased mfALFF over the occipital lobe in the cancer patients compared with the healthy controls; the altered brain regions may be associated with the dorsal attention network (DAN) and may be explained by a compensatory mechanism. Both MMSE and CAMS-R scores showed a positive correlation with mfALFF in the occipital lobe but a negative correlation in the frontoparietal lobe. By contrast, IES-R scores showed a positive correlation with mfALFF in the frontoparietal lobe but a negative correlation in the occipital lobe. These alterations are potentially related to the effects of both chemotherapy and psychological distress. Future research involving a larger sample size of patients with breast cancer is recommended.

Psychiatric, behavioral, and cognitive disorders in patients with extracranial cancers

Patients with cancer may report neuropsychiatric abnormalities including cognitive impairment, behavioral disturbances, and psychiatric disorders that potentially worsen their quality of life, reduce their treatment response, and aggravate their overall prognosis. Neuropsychiatric disturbances have a different pathophysiology, including immuno-inflammatory and neuroendocrine mechanisms, as a consequence of oncologic treatments (chemo- and radio-therapy). Among clinicians involved in the management of such patients, psychiatrists need to pay particular attention in recognizing behavioral disturbances that arise in oncologic patients, and determining those that may be effectively treated with psychotropic medications, psychotherapeutic interventions, and an integration of them. Through the contribution of different clinicians actively involved in the management of oncological patients, the present review is ultimately aimed at updating psychiatrists in relation to the pathophysiological mechanisms responsible for the onset of cognitive, affective, and behavioral syndromes in these patients, along with epidemiologic and clinical considerations and therapeutic perspectives.

Blocking LLT1 (CLEC2D, OCIL)-NKRP1A (CD161) interaction enhances natural killer cell-mediated lysis of triple-negative breast cancer cells

Triple-negative breast cancer (TNBC) is the most invasive form of breast cancer due to an absence of estrogen (ER), progesterone (PR), and human epidermal growth factor-2 (HER2) receptors on the cell surface. TNBC accounts for approximately 12 to 20 percent of all breast cancer cases. The absence of ER, PR, and HER2 receptors on TNBCs and its ability to develop drug resistance renders it difficult to eradicate or retrogress tumor growth with hormonal therapy and chemotherapy. Triple-negative breast cancer is associated with poorer prognosis, increased chance of relapse, and lower chance of survival. Patients with TNBC have poorer outcome to conventional treatments than patients with other types of breast cancer. Natural killer cell-mediated immunotherapy is a promising therapeutic option for patients with TNBC. Natural killer cells contribute to the immune system by recognizing tumor cells through interactions between ligands on tumor cells and natural killer cell receptors. NK cell function is regulated by a net balance of signals from activating and inhibitory receptors interacting with ligands on target cells. Lectin-like Transcript-1 (LLT1, CLEC2D, OCIL) is a ligand that interacts with NK cell receptor NKRP1A (CD161) and inhibits NK cell activation. In this study, we have identified expression of LLT1 on TNBC cell lines MDA-MB-231 and MDA-MB-436 through flow cytometry, western blot, and confocal microscopy. We have demonstrated that blocking LLT1 on TNBCs with antibodies disrupts interaction with NKRP1A and enhances lysis of TNBCs by primary natural killer cells. We have also shown that a gene knockdown of LLT1 decreases cell surface expression of LLT1 on TNBCs and increases NK cell-mediated lysis of these TNBCs. The results suggest that LLT1 on TNBCs function as a method of evasion from immunosurveillance by NK cells. Blocking LLT1-NKRP1A interaction activates lysis by NK cells and will potentially open a new immunotherapeutic strategy for treatment of TNBC.

Biophysics Model of Heavy-Ion Degradation of Neuron Morphology in Mouse Hippocampal Granular Cell Layer Neurons

Exposure to heavy-ion radiation during cancer treatment or space travel may cause cognitive detriments that have been associated with changes in neuron morphology and plasticity. Observations in mice of reduced neuronal dendritic complexity have revealed a dependence on radiation quality and absorbed dose, suggesting that microscopic energy deposition plays an important role. In this work we used morphological data for mouse dentate granular cell layer (GCL) neurons and a stochastic model of particle track structure and microscopic energy deposition (ED) to develop a predictive model of high-charge and energy (HZE) particle-induced morphological changes to the complex structures of dendritic arbors. We represented dendrites as cylindrical segments of varying diameter with unit aspect ratios, and developed a fast sampling method to consider the stochastic distribution of ED by δ rays (secondary electrons) around the path of heavy ions, to reduce computational times. We introduce probabilistic models with a small number of parameters to describe the induction of precursor lesions that precede dendritic snipping, denoted as snip sites. Predictions for oxygen (16O, 600 MeV/n) and titanium (48Ti, 600 MeV/n) particles with LET of 16.3 and 129 keV/μm, respectively, are considered. Morphometric parameters to quantify changes in neuron morphology are described, including reduction in total dendritic length, number of branch points and branch numbers. Sholl analysis is applied for single neurons to elucidate dose-dependent reductions in dendritic complexity. We predict important differences in measurements from imaging of tissues from brain slices with single neuron cell observations due to the role of neuron death through both soma apoptosis and excessive dendritic length reduction. To further elucidate the role of track structure, random segment excision (snips) models are introduced and a sensitivity study of the effects of the modes of neuron death in predictions of morphometric parameters is described. An important conclusion of this study is that δ rays play a major role in neuron morphological changes due to the large spatial distribution of damage sites, which results in a reduced dependence on LET, including modest difference between 16O and 48Ti, compared to damages resulting from ED in localized damage sites.

Neuroinflammatory and cognitive consequences of combined radiation and immunotherapy in a novel preclinical model

Background

Cancer patients often report behavioral and cognitive changes following cancer treatment. These effects can be seen in patients who have not yet received treatment or have received only peripheral (non-brain) irradiation. Novel treatments combining radiotherapy (RT) and immunotherapy (IT) demonstrate remarkable efficacy with respect to tumor outcomes by enhancing the proinflammatory environment in the tumor. However, a proinflammatory environment in the brain mediates cognitive impairments in other neurological disorders and may affect brain function in cancer patients receiving these novel treatments. Currently, gaps exist as to whether these treatments impact the brain in individuals with or without tumors and with regard to the underlying mechanisms.

Results

Combined treatment with precision RT and checkpoint inhibitor IT achieved control of tumor growth. However, BALB/c mice receiving combined treatment demonstrated changes in measures of anxiety levels, regardless of tumor status. C57BL/6J mice with tumors demonstrated increased anxiety, except following combined treatment. Object recognition memory was impaired in C57BL/6J mice without tumors following combined treatment. All mice with tumors showed impaired object recognition, except those treated with RT alone. Mice with tumors demonstrated impaired amygdala-dependent cued fear memory, while maintaining hippocampus-dependent context fear memory. These behavioral alterations and cognitive impairments were accompanied by increased microglial activation in mice receiving immunotherapy alone or combined with RT. Finally, based on tumor status, there were significant changes in proinflammatory cytokines (IFN-γ, IL-6, IL-5, IL-2, IL-10) and a growth factor (FGF-basic).

Materials and Methods

Here we test the hypothesis that IT combined with peripheral RT have detrimental behavioral and cognitive effects as a result of an enhanced proinflammatory environment in the brain. BALB/c mice with or without injected hind flank CT26 colorectal carcinoma or C57BL/6J mice with or without Lewis Lung carcinoma were used for all experiments. Checkpoint inhibitor IT, using an anti-CTLA-4 antibody, and precision CT-guided peripheral RT alone and combined were used to closely model clinical treatment. We assessed behavioral and cognitive performance and investigated the immune environment using immunohistochemistry and multiplex assays to analyze proinflammatory mediators.

Conclusions

Although combined treatment achieved tumor growth control, it affected the brain and induced changes in measures of anxiety, cognitive impairments, and neuroinflammation.

CNS side effects of immune checkpoint inhibitors: preclinical models, genetics and multimodality therapy

Following cancer treatment, patients often report behavioral and cognitive changes. Novel cancer immunotherapeutics have the potential to produce sustained cancer survivorship, meaning patients will live longer with the side effects of treatment. Given the role of inflammatory pathways in mediating behavioral and cognitive impairments seen in cancer, we aim in this review to discuss emerging evidence for the contribution of immune checkpoint blockade to exacerbate these CNS effects. We discuss ongoing studies regarding the ability of immune checkpoint inhibitors to reach the brain and how treatment responses to checkpoint inhibitors may be modulated by genetic factors. We further consider the use of preclinical tumor-models to study the role of tumor status in CNS effects of immune checkpoint inhibitors and multimodality therapy.

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.

Systemic therapies and cognitive impairment for breast cancer: an overview of the current literature

Both endocrine and chemotherapy can be utilized for breast cancer patients' management, in multiple setting (i.e., primary systemic therapy, adjuvant, metastatic treatment). Health-related quality of life in breast cancer survivors can be significantly influenced by cognitive impairment, which has been related in several previously reported experiences to systemic therapies administration. However, although the growing body of literature, the impact of both chemo- and endocrine therapy on cognitive function is currently unclear, due to many confounding factors (i.e., multiple therapies, duration of therapy, comorbidity, age). The aim of the present review is to present an overview of the current literature concerning the possible influence of endocrine and systemic therapy on breast cancer patients' cognitive impairment.

Central Nervous System Injury - A Newly Observed Bystander Effect of Radiation

The unintended side effects of cancer treatment are increasing recognized. Among these is a syndrome of long-term neurocognitive dysfunction called cancer/chemotherapy related cognitive impairment. To date, all studies examining the cognitive impact of cancer treatment have emphasized chemotherapy. Radiation-induced bystander effects have been described in cell culture and, to a limited extent, in rodent model systems. The purpose of this study was to examine, for the first time, the impact of non-brain directed radiation therapy on the brain in order to elucidate its potential relationship with cancer/chemotherapy related cognitive impairment. To address this objective, female BALB/c mice received either a single 16 gray fraction of ionizing radiation to the right hind limb or three doses of methotrexate, once per week for three consecutive weeks. Mice were sacrificed either 3 or 30 days post-treatment and brain injury was determined via quantification of activated astrocytes and microglia. To characterize the effects of non-brain directed radiation on brain glucose metabolism, mice were evaluated by fluorodeoxygluocose positron emission tomography. A single fraction of 16 gray radiation resulted in global decreases in brain glucose metabolism, a significant increase in the number of activated astrocytes and microglia, and increased TNF-α expression, all of which lasted up to 30 days post-treatment. This inflammatory response following radiation therapy was statistically indistinguishable from the neuroinflammation observed following methotrexate administration. In conclusion, non-brain directed radiation was sufficient to cause significant brain bystander injury as reflected by multifocal hypometabolism and persistent neuroinflammation. These findings suggest that radiation induces significant brain bystander effects distant from the irradiated cells and tissues. These effects may contribute to the development of cognitive dysfunction in treated human cancer patients and warrant further study.

Decline in Cognitive Function in Older Adults With Early-Stage Breast Cancer After Adjuvant Treatment

BACKGROUND

The impact of chemotherapy on cognition among elderly patients has received little attention, although such patients are more prone to presenting with age-related cognitive deficits and/or cognitive decline during chemotherapy. The present study assessed the cognitive function in older adults treated for early-stage breast cancer (EBC).

PATIENTS AND METHODS

The participants were newly diagnosed EBC patients aged ≥65 years without previous systemic treatment or neurological or psychiatric disease and matched healthy controls. They underwent two assessments: before starting adjuvant therapy and after the end of chemotherapy (including doxorubicin ± docetaxel [CT+ group], n = 58) or radiotherapy for patients who did not receive chemotherapy (CT- group, n = 61), and at the same interval for the healthy controls (n = 62). Neuropsychological and geriatric assessments were performed. Neuropsychological data were analyzed using the Reliable Change Index.

RESULTS

Forty-nine percent of the patients (mean age, 70 ± 4 years) had objective cognitive decline after adjuvant treatment that mainly concerned working memory. Among these patients, 64% developed a cognitive impairment after adjuvant treatment. Comorbidity was not associated with cognitive decline. No significant difference in objective cognitive decline was found between the two groups of patients; however, the CT+ group had more subjective cognitive complaints after treatment (p = .008). The oldest patients (aged 70-81 years) tended to have more objective decline with docetaxel (p = .05).

CONCLUSION

This is the largest published study assessing cognitive function in older adults with EBC that included a group of patients treated with modern chemotherapy regimens. Approximately half the patients had objective cognitive decline after adjuvant treatment. The oldest patients were more likely to have cognitive decline with chemotherapy, particularly with docetaxel.

IMPLICATIONS FOR PRACTICE

This is the largest published study assessing cognitive function in older adults with early-stage breast cancer that included a group of patients treated with modern chemotherapy regimens. Approximately half the patients had objective cognitive decline after adjuvant treatment. The oldest patients were more likely to have cognitive decline with chemotherapy, particularly with docetaxel. Cognitive deficits could affect patients' quality of life and their compliance to treatment. Assessing cognitive dysfunctions in the elderly cancer population is a challenge in clinical practice, but it could influence the choice of the most appropriate therapy, including the use of oral drugs.

A feasibility study exploring the role of pre-operative assessment when examining the mechanism of 'chemo-brain' in breast cancer patients

Background

Women receiving chemotherapy treatment for breast cancer may experience problems with their memory and attention (cognition), which is distressing and interferes with quality of life. It is unclear what causes or contributes to the problems they report: psychological distress, fatigue, coping style, or specific biological changes for example to pro inflammatory cytokines. Research shows however, that approximately a third of women with breast cancer perform poorly on tests of cognition before commencing chemotherapy. We aimed to examine the acceptability and relevance of pre-surgical assessments (bloods, brain imaging, cognitive tests and self-report questionnaires) when investigating the phenomenon of ‘chemo-brain’ and investigate whether inflammatory markers mediate chemotherapy-induced neuropsychological impairments in women treated for breast cancer.

Methods

Women with early stage breast cancer completed neuropsychological and quality of life assessments at T1 (pre-surgery), T2 (post-surgery before chemotherapy) and T3 (6 months later). Blood cytokine levels were measured at the same time points and brain imaging was performed at T1 and T3.

Results

In total, 14/58 women participated (8 chemotherapy, 6 non-chemotherapy). Prior to the start of chemotherapy a decline in cognitive performance compared to baseline was observed in one participant. At T3 women who received chemotherapy reported poorer quality of life and greater fatigue. Increases in soluble tumour necrosis factor receptor II (sTNFRII), interleukin-6, interleukin-10 and vascular endothelial growth factor occurred post chemotherapy only. Levels of sTNFRII were inversely correlated with grey matter volume (GMV) of the right posterior insula in both groups. At T3, the chemotherapy group displayed a greater reduction in GMV in the subgenual and dorsal anterior cingulate, and the inferior temporal gyrus.

Conclusions

Pre-operative recruitment to the study was challenging; however, the lack of significant changes in blood cytokine levels and neuropsychological tests at T2 implies that post surgery may be a valid baseline assessment, but this needs further investigation in a larger study. The preliminary results support the hypothesis that chemotherapy induced fatigue is mediated by a change in peripheral cytokine levels which could explain some symptoms of ‘chemo brain’ experienced by patients.

Neurotoxicity in breast cancer survivors ≥10 years post-treatment is dependent on treatment type

Adjuvant chemotherapy (CT) for breast cancer (BC) is associated with very late side-effects on brain function and structure. However, little is known about neurotoxicity of specific treatment regimens. To compare neurotoxicity profiles after different treatment strategies, we used neurocognitive testing and multimodality MRI in BC survivors randomized to high-dose (HI), conventional-dose (CON-) CT or radiotherapy (RT) only and a healthy control (HC) group. BC survivors who received CON-CT (n = 20) and HC (n = 20) were assessed using a neurocognitive test battery and multimodality MRI including 3D-T1, Diffusion Tensor Imaging (DTI) and 1H-MR spectroscopy (1H-MRS) to measure various aspects of cerebral white (WM) and gray matter (GM). Data were compared to previously assessed groups of BC survivors who received HI-CT (n = 17) and RT-only (n = 15). Testing took place on average 11.5 years post-CT. 3D-T1 showed focal GM volume reductions both for HI-CT and CON-CT compared to RT-only (p < .004). DTI-derived mean diffusivity and 1H-MRS derived N-acetyl aspartate showed WM injury specific to HI-CT but not CON-CT (p < .05). Residual effects were revealed in the RT-only group compared to HC on MRI and neurocognitive measurements (p < .05). Ten years after adjuvant CT for BC lower cerebral GM volume was found in HI as well as CON-CT BC survivors whereas injury to WM is restricted to HI-CT. This might indicate that WM brain changes after BC treatment may show more pronounced (partial) recovery than GM. Furthermore, our results suggest residual neurotoxicity in the RT-only group, which warrants further investigation.

Prevalence of perceived cognitive dysfunction in survivors of a wide range of cancers: results from the 2010 LIVESTRONG survey

PURPOSE

With cancer survivors now numbering over 13 million in the United States, and expected to continue to increase, it is important to consider the needs of this growing population. In the literature, one of the most common complaints by cancer survivors is perceived cognitive dysfunction. Since the preponderance of the research has focused on breast cancer survivors, the purpose of the present study was to explore the prevalence and correlates of perceived cognitive dysfunction in a large sample of cancer survivors with representation across a wide range of different types of cancer.

METHODS

A sample of 3108 post-treatment cancer survivors completed the 2010 LIVESTRONG survey as part of a larger study of cancer survivorship. Respondents completed standardized questions regarding current and past perceived cognitive dysfunction, as well as depressive symptoms, and demographic and medical variables.

RESULTS

Current perceived cognitive dysfunction was reported by nearly half of respondents (45.7%), across a wide range of cancer types, with the highest prevalence among survivors of central nervous system cancers. Receiving chemotherapy and current report of depressive symptoms were both strongly associated with current perceived cognitive dysfunction.

CONCLUSION

These findings contribute to a growing appreciation of the high prevalence of perceived cognitive dysfunction in survivors of a wide range of cancer types and the potential interactive effect of concurrent symptoms of depression. These findings highlight a need to develop more effective means of preventing or reducing cognitive dysfunction in cancer survivors.

IMPLICATIONS FOR CANCER SURVIVORS

Perceived cognitive dysfunction was reported in a wide range of cancer survivors. The potential interactive effect of symptoms of depression suggests the need to develop interventions targeting both cognitive dysfunction and depression to achieve improvements in cognitive functioning.

The effect of estrogen synthesis inhibition on hippocampal memory

17-Beta-estradiol (E2) facilitates long term-potentiation (LTP) and increases spine synapse density in hippocampal neurons of ovariectomized rodents. Consistent with these beneficial effects on the cellular level, E2 improves hippocampus-dependent memory. A prominent approach to study E2 effects in rodents is the inhibition of its synthesis by letrozole, which reduces LTPs and spine synapse density. In the current longitudinal functional magnetic resonance imaging (fMRI) study, we translated this approach to humans and compared the impact of E2 synthesis inhibition on memory performance and hippocampal activity in post-menopausal women taking letrozole (n = 21) to controls (n = 24). In particular, we employed various behavioral memory paradigms that allow the disentanglement of hippocampus-dependent and -independent memory. Consistent with the literature on rodents, E2 synthesis inhibition specifically impaired hippocampus-dependent memory, however, this did not apply to the same degree to all of the employed paradigms. On the neuronal level, E2 depletion tended to decrease hippocampal activity during encoding, whereas it increased activity in the anterior cingulate and the dorsolateral prefrontal cortex. We thus infer that the inhibition of E2 synthesis specifically impairs hippocampal functioning in humans, whereas the increased prefrontal activity presumably reflects a compensatory mechanism, which is already known from studies on cognitive aging and Alzheimer's disease.

Affective science perspectives on cancer control: strategically crafting a mutually beneficial research agenda

Cancer control research involves the conduct of basic and applied behavioral and social sciences to reduce cancer incidence, morbidity, and mortality and improve quality of life. Given the importance of behavior in cancer control, fundamental research is necessary to identify psychological mechanisms underlying cancer risk, prevention, and management behaviors. Cancer prevention, diagnosis, and treatment are often emotionally laden. As such, affective science research to elucidate questions related to the basic phenomenological nature of emotion, stress, and mood is necessary to understand how cancer control can be hindered or facilitated by emotional experiences. To date, the intersection of basic affective science research and cancer control remains largely unexplored. The goal of this article is to outline key questions in the cancer control research domain that provide an ecologically valid context for new affective science discoveries. We also provide examples of ways in which basic affective discoveries could inform future cancer prevention and control research. These examples are not meant to be exhaustive or prescriptive but instead are offered to generate creative thought about the promise of a cancer research context for answering basic affective science questions. Together, these examples provide a compelling argument for fostering collaborations between affective and cancer control scientists.

A meta-analysis of cognitive impairment and decline associated with adjuvant chemotherapy in women with breast cancer

A meta-analysis was performed to quantify the magnitude and nature of the association between adjuvant chemotherapy and performance on a range of cognitive domains among breast cancer patients. A total of 27 studies (14 cross-sectional, 8 both cross-sectional and prospective, and 5 prospective) were included in the analyses, involving 1562 breast cancer patients who had undergone adjuvant chemotherapy and 2799 controls that included breast cancer patients who did not receive adjuvant chemotherapy. A total of 737 effect sizes (Cohen's d) were calculated for cross-sectional and prospective longitudinal studies separately and classified into eight cognitive domains. The mean effect sizes varied across cross-sectional and prospective longitudinal studies (ranging from -1.12 to 0.62 and -0.29 to 1.12, respectively). Each cognitive domain produced small effect sizes for cross-sectional and prospective longitudinal studies (ranging from -0.25 to 0.41). Results from cross-sectional studies indicated a significant association between adjuvant chemotherapy and cognitive impairment that held across studies with varied methodological approaches. For prospective studies, results generally indicated that cognitive functioning improved over time after receiving adjuvant chemotherapy. Greater cognitive impairment was reported in cross-sectional studies comparing chemotherapy groups with healthy control groups. Results suggested that cognitive impairment is present among breast cancer patients irrespective of a history of chemotherapy. Prospective longitudinal research is warranted to examine the degree and persisting nature of cognitive impairment present both before and after chemotherapy, with comparisons made to participants' cognitive function prior to diagnosis. Accurate understanding of the effects of chemotherapy is essential to enable informed decisions regarding treatment and to improve quality of life among breast cancer patients.

Altered cerebral blood flow one month after systemic chemotherapy for breast cancer: a prospective study using pulsed arterial spin labeling MRI perfusion

Cerebral structural and functional alterations have been reported after chemotherapy for non-CNS cancers, yet the causative mechanism behind these changes remains unclear. This study employed a novel, non-invasive, MRI-based neuroimaging measure to provide the first direct longitudinal measurement of resting cerebral perfusion in breast cancer patients, which was tested for association with changes in cognitive function and gray matter density. Perfusion was measured using pulsed arterial spin labeling MRI in women with breast cancer treated with (N = 27) or without (N = 26) chemotherapy and matched healthy controls (N = 26) after surgery before other treatments (baseline), and one month after chemotherapy completion or yoked intervals. Voxel-based analysis was employed to assess perfusion in gray matter; changes were examined in relation to overall neuropsychological test performance and frontal gray matter density changes measured by structural MRI. Baseline perfusion was not significantly different across groups. Unlike control groups, chemotherapy-treated patients demonstrated significantly increased perfusion post-treatment relative to baseline, which was statistically significant relative to controls in the right precentral gyrus. This perfusion increase was negatively correlated with baseline overall neuropsychological performance, but was not associated with frontal gray matter density reduction. However, decreased frontal gray matter density was associated with decreased perfusion in bilateral frontal and parietal lobes in the chemotherapy-treated group. These findings indicate that chemotherapy is associated with alterations in cerebral perfusion which are both related to and independent of gray matter changes. This pattern of results suggests the involvement of multiple mechanisms of chemotherapy-induced cognitive dysfunction. Additionally, lower baseline cognitive function may be a risk factor for treatment-associated perfusion dysregulation. Future research is needed to clarify these mechanisms, identify individual differences in susceptibility to treatment-associated changes, and further examine perfusion change over time in survivors.

Association between adjuvant regional radiotherapy and cognitive function in breast cancer patients treated with conservation therapy

Although protracted cognitive impairment has been reported to occur after radiotherapy even when such therapy is not directed to brain areas, the mechanism remains unclear. This study investigated whether breast cancer patients exposed to local radiotherapy showed lower cognitive function mediated by higher plasma interleukin (IL)-6 levels than those unexposed. We performed the Wechsler Memory Scale-Revised (WMS-R) and measured plasma IL-6 levels for 105 breast cancer surgical patients within 1 year after the initial therapy. The group differences in each of the indices of WMS-R were investigated between cancer patients exposed to adjuvant regional radiotherapy (n = 51) and those unexposed (n = 54) using analysis of covariance. We further investigated a mediation effect by plasma IL-6 levels on the relationship between radiotherapy and the indices of WMS-R using the bootstrapping method. The radiotherapy group showed significantly lower Immediate Verbal Memory Index and Delayed Recall Index (P = 0.001, P = 0.008, respectively). Radiotherapy exerted an indirect effect on the lower Delayed Recall Index of WMS-R through elevation of plasma IL-6 levels (bootstrap 95% confidence interval = −2.6626 to −0.0402). This study showed that breast cancer patients exposed to adjuvant regional radiotherapy in conservation therapy might have cognitive impairment even several months after their treatment. The relationship between the therapy and the cognitive impairment could be partially mediated by elevation of plasma IL-6 levels.

Longitudinal study of cognitive dysfunctions induced by adjuvant chemotherapy in colon cancer patients

BACKGROUND

Chemotherapy can induce cognitive impairment in cancer patients. The main goal of this longitudinal study was to determine the incidence, characteristics, and duration of cognitive dysfunction in patients treated with adjuvant chemotherapy for colon cancer.

PATIENTS AND METHODS

We assessed cognitive function, quality of life, anxiety and depression, fatigue, and hemoglobin levels in colon cancer patients at three assessment points: pre-chemotherapy (n=81), post-chemotherapy (n=73), and after 6-month follow-up (n=54). All patients were treated with oxaliplatin plus 5-fluorouracil/leucovorin (FOLFOX4) for 6 months.

RESULTS

Thirty patients (37%) had cognitive impairment in the pre-chemotherapy evaluation, mainly in processing speed and psychomotor executive function (Trail Making Test A and B). At the end of treatment, the main domain affected was the verbal memory, with an acute decline detected in 56% of patients. Fifty-four percent of the patients improved their dysfunction after 6 months of follow-up, whereas 18 (33%) of them showed worsening in at least one test. Cognitive impairment was most common in older patients and in those with less years of education. Quality of life, anxiety, depression, fatigue, and hemoglobin did not influence the results of the cognitive tests.

CONCLUSIONS

Adjuvant FOLFOX4 in patients with colon cancer can have a negative effect on verbal memory. This deterioration is usually mild and transient.

Self-Reported History of Chemotherapy and Cognitive Decline in Adults Aged 60 and Older: The PATH Through Life Project

BACKGROUND

There is a lack of data from cohort studies assessing cognitive function prior to and after chemotherapy. We evaluated the effect of self-reported cancer chemotherapy on cognitive function in a cohort assessed at baseline, 4 and 8 years.

METHODS

Participants were from the population-based PATH Through Life Study. Of the 2,551 participants aged 60-64 at baseline without cognitive impairment, 1,949 completed wave 3 and had data on cancer and chemotherapy and cognitive function. Linear mixed models were used to analyze the data.

RESULTS

At wave 3, participants reporting history of chemotherapy (n = 76) had lower scores on memory, processing speed, and executive function compared with those reporting cancer without chemotherapy (n = 289) and no cancer history (n = 1508). After adjustment for depression and disability, effects remained for processing speed and memory. Chemotherapy prior to the study commencement (n = 24), but not between waves 1 and 3 (n = 81), was associated with greater decline in delayed recall (β = -.21 [95% CI -0.38, -.03], p = .02) and digits backwards β = -.05 [95% CI -0.09, -.01], p = .02) over 8 years compared with those with no cancer history (n = 1562). Women reporting chemotherapy for breast cancer after wave 1 (n = 26) had slower choice reaction time (-0.81 (95% CI -1.28, -0.34), p = .001) but did not decline faster on this measure compared with those reporting no breast cancer history (n = 818).

CONCLUSIONS

Results suggest chemotherapy prior to old age is associated with faster decline in memory in late life but that it does not affect decline in other domains of cognitive function.