Effects of adjuvant treatment on cognitive function in women with early breast cancer

Adjuvant aromatase inhibitor treatment worsens depressive symptoms and sleep quality in postmenopausal women with localized breast cancer: A one-year follow-up study

First-line treatment in postmenopausal women with estrogen- and/or progesterone-positive breast cancer consists of aromatase inhibitors (AROi). The ability of AROi to promote or worsen cognitive function, depressive symptoms, sleep quality and performance in basic activities of daily life as primary and concomitant outcomes in long longitudinal studies in post-menopausal women has been seldom investigated. This study is a cohort trial which aimed to determine if there were differences in cognitive function assessment, depressive symptoms, and sleep quality after 1 year under AROi treatment and to determine the interrelations between these symptoms.

METHODS

A prospective 1-year longitudinal study was performed in a representative sample of tertiary hospital. Women with localized breast cancer newly treated with AROi therapy were evaluated for cognitive functions, depressive symptoms, sleep problems and ability to perform basic activities of the daily life at baseline and after 6 months and 12 months under adjuvant AROi treatment.

RESULTS

Analysis of cognitive functions by the Mini-Mental State Examination (MMSE) scores did not show significantly worsening under AROi treatment after 6 months and 12 months of treatment compared to the baseline. Analysis of depressive symptoms with the Geriatric Depression Scale and sleep quality with the Athens Insomnia Scale (AIS) scores showed significant (p < 0.05) changes after 6 and 12 months of treatment with AROi, with women describing more depressive symptoms and more sleep disturbances.

CONCLUSIONS

Our study found impairments in sleep quality and an increase in depressive symptoms, which has important implications for clinicians as they impair quality of life and adherence to treatment.

Blood-Based Biomarkers of Cancer-Related Cognitive Impairment in Non-Central Nervous System Cancer: A Scoping Review

This scoping review was designed to synthesize the extant literature on associations between subjective and/or objective measures of cancer-related cognitive impairment (CRCI) and blood-based biomarkers in adults with non-central nervous system cancers. The literature search was done for studies published from the start of each database searched (i.e., MEDLINE, Embase, PsycINFO, Cumulative Index to Nursing and Allied Health Literature, Cochrane Central Register of Controlled Trials, grey literature) through to October 20, 2021. A total of 95 studies are included in this review. Of note, a wide variety of biomarkers were evaluated. Most studies evaluated patients with breast cancer. A variety of cognitive assessment measures were used. The most consistent significant findings were with various subjective and objective measures of CRCI and levels of interleukin-6 and tumor necrosis factor. Overall, biomarker research is in an exploratory phase. However, this review synthesizes findings and proposes directions for future research.

Effects of Endocrine Therapy on Cognitive Function in Patients with Breast Cancer: A Comprehensive Review

Simple Summary

Many persons diagnosed with breast cancer are treated with endocrine therapy and will experience the side effects of endocrine therapy. Cognitive adverse effects of endocrine therapy are increasingly being recognised, and can significantly affect quality of life, adherence and treatment outcome. This review aims to discuss the nature of cognitive dysfunction associated with endocrine therapy, the mechanisms underpinning its development, and evidence-based management strategies.

Abstract

Endocrine therapy forms the backbone of systemic therapy for the majority of persons with early and late-stage breast cancer. However, the side effects can negatively affect quality of life, and impact treatment adherence and overall oncological outcomes. Adverse effects on cognition are common, underreported and challenging to manage. We aim to describe the nature, incidence, risk factors and underlying mechanisms of endocrine therapy-induced cognitive dysfunction. We conducted a comprehensive literature review of the studies reporting on cognitive dysfunction associated with endocrine therapies for breast cancer. We also summarise prevention and treatment strategies, and ongoing research. Given that patients are taking endocrine therapies for longer durations than ever before, it is essential that these side effects are managed pro-actively within a multi-disciplinary team in order to promote adherence to endocrine therapy and improve patients’ quality of life.

Sickness absence and disability pension among swedish women prior to breast cancer relapse with a special focus on the roles of treatment and comorbidity

OBJECTIVE

We aimed to determine the longitudinal prevalence and the predictors of sickness absence (SA) and disability pension (DP) in breast cancer (BC) women who eventually developed relapse.

METHODS

A total of 1293 BC women, who were ages 20-63 years, diagnosed between 1996 and 2011 and by 2016 had all developed relapse, were identified in Swedish registers and were followed from two years before to five years after their primary diagnosis, while they were relapse-free. Annual prevalence of SA and DP was calculated. Logistic regression was used to estimate adjusted odds ratios (AOR) for long-term SA (>30 days) at one (y1) and three (y3) years post-diagnosis.

RESULTS

Prevalence of long-term SA was 68.1% in y1 and 16.3% in y5. Prevalence of DP progressively increased from 16.3% in y1 to 29.0% in y5. Predictors of long-term SA included age <50 years (y1:AOR = 1.79 [1.39-2.29]), TNM stage III (y1:AOR = 1.54 [1.03-2.31]; y3:AOR = 2.21 [1.32-3.72]), metastasis (y1:AOR = 1.64 [1.26-2.12]; y3:AOR = 1.51 [1.05-2.18]), comorbidity (y1:AOR = 2.41 [1.55-3.76]; y3 AOR = 4.62 [2.49-8.57]) and any combination of radiotherapy, chemotherapy and hormonal therapy (y1:AOR = 2.05-5.71).

CONCLUSION

Among BC women who later developed relapse, those who had higher stages of BC, had comorbidity and received neoadjuvant and/or adjuvant therapy were at significantly higher risk of needing long-term SA after their diagnosis.

Changes in Attentional Function in Patients From Before Through 12 Months After Breast Cancer Surgery

CONTEXT

Although approximately 75% of patients with breast cancer report changes in attentional function, little is known about how demographic, clinical, symptom, and psychosocial adjustment (e.g., coping) characteristics influence changes in the trajectories of attentional function over time.

OBJECTIVES

This study evaluated interindividual variability in the trajectories of self-reported attentional function and determined which demographic, clinical, symptom, and psychosocial adjustment characteristics were associated with initial levels and with changes in attentional function from before through 12 months after breast cancer surgery.

METHODS

Before surgery, 396 women were enrolled. Attentional Function Index (AFI) was completed before and nine times within the first 12 months after surgery. Hierarchical linear modeling was used to determine which characteristics were associated with initial levels and trajectories of attentional function.

RESULTS

Given an estimated preoperative AFI score of 6.53, for each additional month, the estimated linear rate of change in AFI score was an increase of 0.054 (P < 0.001). Higher levels of comorbidity, receipt of adjuvant chemotherapy, higher levels of trait anxiety, fatigue, and sleep disturbance, and lower levels of energy and less sense of control were associated with lower levels of attentional function before surgery. Patients who had less improvements in attentional function over time were nonwhite, did not have a lymph node biopsy, had received hormonal therapy, and had less difficulty coping with their disease.

CONCLUSION

Findings can be used to identify patients with breast cancer at higher risk for impaired self-reported cognitive function and to guide the prescription of more personalized interventions.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

IMPLICATIONS FOR CANCER SURVIVORS

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

Cognitive impairment after cytotoxic chemotherapy

Background

Neurotoxicity is a frequent side effect of cytotoxic chemotherapy and affects a large number of patients. Despite the high medical need, few research efforts have addressed the impact of cytotoxic agents on cognition (ie, postchemotherapy cognitive impairment; PCCI). One unsolved question is whether individual cytotoxic drugs have differential effects on cognition. We thus examine the current state of research regarding PCCI. Neurological symptoms after targeted therapies and immunotherapies are not part of this review.

Methods

A literature search was conducted in the PubMed database, and 1215 articles were reviewed for predefined inclusion and exclusion criteria. Thirty articles were included in the systematic review.

Results

Twenty-five of the included studies report significant cognitive impairment. Of these, 21 studies investigated patients with breast cancer. Patients mainly received combinations of 5-fluorouracil, epirubicin, cyclophosphamide, doxorubicin, and taxanes (FEC/FEC-T). Five studies found no significant cognitive impairment in chemotherapy patients. Of these, 2 studies investigated patients with colon cancer receiving 5-fluorouracil and oxaliplatin (FOLFOX). Independent risk factors for PCCI were patient age, mood alterations, cognitive reserve, and the presence of apolipoprotein E e4 alleles.

Conclusions

There is evidence that certain chemotherapy regimens cause PCCI more frequently than others as evidenced by 21 out of 23 studies in breast cancer patients (mainly FEC-T), whereas 2 out of 3 studies with colon cancer patients (FOLFOX) did not observe significant changes. Further studies are needed defining patient cohorts by treatment protocol in addition to cancer type to elucidate the effects of individual cytotoxic drugs on cognitive functions.

Cognitive effects of adjuvant endocrine therapy in older women treated for early-stage breast cancer: a 1-year longitudinal study

PURPOSE

Evidence suggests endocrine therapy (ET) for breast cancer (BC) has adverse cognitive effects, but its specific effects on older women are unknown. This is despite the fact that older women are at increased risk of both breast cancer (BC) and cognitive decline relative to younger women. This study prospectively examined the cognitive effects of ET in a cohort of older BC patients. Our primary outcome measure was change in verbal memory, the cognitive domain most consistently affected by estrogen deprivation.

METHODS

Forty-two chemotherapy-naïve women age 60+, without dementia and recently diagnosed with hormone receptor-positive BC, completed neuropsychological tests at the time of ET initiation and after 1 year of treatment. Change in age-standardized verbal memory performance was examined using paired t tests. To assess a broader range of potential cognitive effects, we also examined changes in visual memory, processing speed, frontal executive function, and perceptual reasoning.

RESULTS

Participants exhibited significant decline from baseline to 1 year in verbal memory (p = 0.01). This decline was small to moderate in effect size (d = - 0.40). Performance on other domains did not change significantly over the year (all p > 0.05).

CONCLUSIONS

Our findings suggest potentially detrimental effects of ET on verbal memory in older women after just 1 year of treatment. Given that ET is prescribed for courses of 5 to 10 years, additional studies examining longer-term effects of treatment in older women are critical.

Electrophysiological Measure of Impaired Information Processing in Drivers with Hematological Malignancy

The broad goal of this study is to measure remote effects of cancer on brain physiology and behaviors that underpin instrumental activities of daily living such as automobile driving. Studies of hematological malignancies (HM) have demonstrated impairments in multiple brain functions shown to be critical for safe automobile driving. In the current pilot study, brain physiology during driving simulation was examined in 14 HM patients and 13 healthy comparison drivers. Electroencephalography was used to measure the eye fixation-related potential (EFRP)-a positive amplitude deflection evoked approximately 100 milliseconds after eye movement termination. Previous studies have demonstrated sensitivity of EFRP activity to information-processing capacity. All drivers completed visual search tasks to evaluate the relationship between driving-related changes in performance and EFRP activity. Results showed smaller EFRP amplitudes in drivers who had: (1) greater driving-related changes in visual search performance (p = 0.03, Cohen's d = 0.91); and (2) HM diagnosis (p = 0.18, Cohen's d = 0.54). Extending previous studies, these results provide neural evidence of reduced information-processing capacity associated with cancer diagnosis. Future large-scale studies are needed to confirm these results, given the high level of uncertainty and small sample size. This study provides a novel platform for linking changes in brain physiology and safety-critical driving behaviors.

The cognitive effects of endocrine therapy in survivors of breast cancer: A prospective longitudinal study up to 6 years after treatment

BACKGROUND

After treatment of primary breast cancer, endocrine therapy (ET) is prescribed for patients with hormone receptor-positive cancers. Despite ET recommendations of 5 to 10 years of treatment, to the authors' knowledge there is little prospective study of its impact on cognitive function over an extended period of time. ET has known pharmacologic effects on the brain. Cognitive side effects are a concern for many women, with mixed findings reported in various studies. The current prospective longitudinal study examined the neuropsychological effects of ET over time, up to 6 years after treatment.

METHODS

A total of 189 survivors of early-stage breast cancer enrolled in the study prior to initiating ET if prescribed, and were followed at 6 months (175 patients), 12 months (173 patients), and for 3 to 6 years (102 patients) with self-report and neuropsychological assessments. Using linear mixed models, the authors examined whether neuropsychological performance or impairment rates differed over time based on whether or not ET was received.

RESULTS

The authors did not find any effect of ET on neuropsychological performance or impairment at any time point among survivors who received it compared with women who did not. However, those who participated in the 3-year to 6-year year visit demonstrated better executive function at baseline.

CONCLUSIONS

In the current observational cohort study, no detrimental effect of ET on cognitive function was identified in survivors of early-stage breast cancer receiving treatment with ET compared with those who were not.

Cognitive impairment following chemotherapy for breast cancer: The impact of practice effect on results

Chemotherapy-Related Cognitive Impairment (CRCI) can be an adverse effect in women treated for breast cancer. Some longitudinal studies reported deficits in attention, memory, and executive function following treatment, but other studies did not find cognitive changes. It is known that practice effects (PE) on repeated assessments with cognitive tests contribute to the discrepancies in these results, but its influence on scores has not been systematically explored. The present study examines the impact of PE on retest scores in a group of women with breast cancer treated with chemotherapy and evaluated longitudinally.

METHOD

51 women with breast cancer treated with a combination of 5-fluorouracil, epirubicin, and cyclophosphamide with or without taxanes were assessed after surgery but before chemotherapy (T1), post-chemotherapy (T2), and at one year after T2 (T3). Longitudinal changes on cognitive performance were analyzed twice: when retest scores were not corrected for PE and when correction for PE was applied to T2 and T3 scores.

RESULTS

When PE was not corrected, progressive improvement over time in measures of memory and divided attention at T2 and T3 was observed. In contrast, when PE was corrected, worsening was found in measures of memory, fluency, executive function, and attention at T2 and in attention and executive function at T3. Results after correction for PE are in line with previous longitudinal studies that report cognitive impairment after treatment with chemotherapy for breast cancer.

CONCLUSION

Accounting for PE is recommended to identify true change on cognition through treatment with chemotherapy for breast cancer.

Cognitive Changes in Cancer Survivors

Advances in cancer treatments have led to substantially improved survival for patients with cancer. However, many patients experience changes in cognition as a side effect of both cancer and cancer treatment. This occurs with both central nervous system (CNS) tumors and non-CNS tumors and in both children and adults. Studies of patients with non-CNS cancer have shown that cancer-related cognitive impairment (CRCI), which can include changes in memory, executive function, attention, and processing speed, occurs in up to 30% of patients prior to any treatment and in up to 75% of patients during treatment. A subset of patients with non-CNS and CNS cancer appear to be at higher risk for CRCI, so much research has gone into identifying who is vulnerable. Risk factors for CRCI in adults include cognitive reserve, age, genetic factors, and ethnicity; risk factors for children include genetic factors, female sex, younger age at diagnosis, chemotherapy dose, and both dose and field size for radiation. Although the field has made substantial strides in understanding and treating CRCI, more research is still needed to improve outcomes for both pediatric and adult cancer survivors.

Cognitive Effects of Cancer and Cancer Treatments

As the population of cancer survivors has grown into the millions, there has been increasing emphasis on understanding how the late effects of treatment affect survivors' ability to return to work/school, their capacity to function and live independently, and their overall quality of life. This review focuses on cognitive change associated with cancer and cancer treatments. Research in this area has progressed from a pharmacotoxicology perspective to a view of the cognitive change as a complex interaction of aspects of the treatment, vulnerability factors that increase risk for posttreatment cognitive decline, cancer biology, and the biology of aging. Methodological advances include the development of (a) measurement approaches that assess more fine-grained subcomponents of cognition based on cognitive neuroscience and (b) advanced statistical approaches. Conceptual issues that arise from this multidimensional perspective are described in relation to future directions, understanding of mechanisms, and development of innovative interventions.

Cognitive sequelae of endocrine therapy in women treated for breast cancer: a meta-analysis

PURPOSE

Evidence suggests anti-estrogen endocrine therapy (ET) is associated with adverse cognitive effects; however, findings are based on small samples and vary in the cognitive abilities affected. We conducted a meta-analysis to quantitatively synthesize the evidence.

METHODS

Electronic databases were searched in November 2016. Fourteen studies totaling 911 BC patients on aromatase inhibitors (AIs) or tamoxifen (TAM) and 911 controls (i.e., non-cancer controls and BC controls not using ET) were included. Neuropsychological tests were categorized into six domains. Effect sizes were computed to compare (1) ET patients versus controls and (2) TAM patients versus AI patients.

RESULTS

In cross-sectional comparisons, ET patients performed worse than control groups on verbal learning/memory, visual learning/memory, frontal executive function, and processing speed, but did not differ on psychomotor efficiency or visuospatial function. Subgroup analyses revealed that verbal learning/memory was the only domain where ET patients performed worse than both non-cancer and BC controls. In other domains, ET patients and BC controls performed equivalently. Regarding change from pre-treatment performance, ET patients did not differ from controls on any domain. TAM and AI patients did not from one another differ overall; however, subgroup analyses indicated that TAM patients performed better than non-steroidal AI patients on several domains, but showed few performance differences relative to steroidal AI patients.

CONCLUSIONS

Verbal learning/memory was the only domain where ET patients performed worse than both non-cancer and BC controls, suggesting specific adverse effects on this domain. Additional studies assessing change from pre-treatment performance and differences between steroidal and non-steroidal AIs are warranted.

Cognition, quality-of-life, and symptom clusters in breast cancer: Using Bayesian networks to elucidate complex relationships

OBJECTIVE

Breast cancer patients frequently complain of cognitive dysfunction during chemotherapy. Patients also report experiencing a cluster of sleep problems, fatigue, and depressive symptoms during chemotherapy. We aimed to understand the complex dynamic interrelationships of depression, fatigue, and sleep to ultimately elucidate their role in cognitive performance and quality of life amongst breast cancer survivors undergoing chemotherapy treatment.

METHODS

Our study sample comprised 74 newly diagnosed stage I to III breast cancer patients scheduled to receive chemotherapy. An objective neuropsychological test battery and self-reported fatigue, mood, sleep quality, and quality of life were collected at 3 time points: before the start of chemotherapy (baseline: BL), at the end of cycle 4 chemotherapy (C4), and 1 year after the start of chemotherapy (Y1). We applied novel Bayesian network methods to investigate the role of sleep/fatigue/mood on cognition and quality of life prior to, during, and after chemotherapy.

RESULTS

The fitted network exhibited strong direct and indirect links between symptoms, cognitive performance, and quality of life. The only symptom directly linked to cognitive performance was C4 sleep quality; at C4, fatigue was directly linked to sleep and thus indirectly influenced cognitive performance. Mood strongly influenced concurrent quality of life at C4 and Y1. Regression estimates indicated that worse sleep quality, fatigue, and mood were negatively associated with cognitive performance or quality of life.

CONCLUSIONS

The Bayesian network identified local structure (eg, fatigue-mood-QoL or sleep-cognition) and possible intervention targets (eg, a sleep intervention to reduce cognitive complaints during chemotherapy).

Verbal memory in breast cancer patients treated with chemotherapy with doxorubicin and cyclophosphamide

Memory is one of the crucial human cognitive functions, and deficits in memory processes may lead to difficulties in everyday functioning. The aim of this study was to analyse the effect of anthracycline-based adjuvant chemotherapy (AC) used in breast cancer treatment on verbal memory and learning. We also evaluated the relationship between verbal memory and psychological, somatic and socio-demographic factors. The study was carried out on a group of 31 women with early breast cancer treated with adjuvant chemotherapy and 30 healthy controls. The patients underwent neuropsychological assessment using the Rey Auditory Verbal Learning Test at three time points: before chemotherapy, mid-chemotherapy and post-chemotherapy. The examination in the controls was conducted at the same time intervals. We found an association between AC-schema chemotherapy and deficits in delayed memory. A deterioration in performance after treatment was observed in 19% of patients. The results showed no deterioration of immediate memory or the verbal learning process. Moreover, a positive relationship was shown between the level of education, physical fitness and the functioning of verbal memory. The results of the study also indicate that age and hormonal status are factors that may increase the possibility of deficits in verbal memory after AC-schema chemotherapy.

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.

Cognitive Impairment in a Subset of Breast Cancer Patients After Systemic Therapy-Results From a Longitudinal Study

CONTEXT

Studies indicate adverse effects of breast cancer (BC) and cancer treatment on cognitive function.

OBJECTIVES

To investigate the effects of systemic treatment on cognitive performance in BC patients.

METHODS

Participants were BC patients scheduled to receive systemic treatment (BC + SYST; n = 31), or no systemic treatment (BC; n = 24) and no-cancer (NC) controls (n = 33). Neuropsychological examinations were used to study cognitive performance on 18 tests grouped into eight cognitive domains, before adjuvant treatment (T1) and six months after chemotherapy (T2), or at similar intervals. We also assessed health-related quality of life, anxiety and depression, mood, stress, and cognitive problems. Analysis of variance was used to assess group differences of cognitive performance and multivariate normative comparison to classify impairment, comparing scores of each participant against the distribution of the scores of NC controls.

RESULTS

Of BC + SYST, 16% were cognitively impaired at T2, compared to 4% in BC and 6% in NC. Although not significant, we observed moderate effect sizes for worse performance in the BC + SYST group compared to NC (Flanker congruent [effect size {ES} = 0.44] and stimulus incongruent [ES = 0.44]) and compared to BC (Controlled Oral Word Association Test [ES = 0.47], digit span [ES = 0.41], and Hopkins Verbal Learning Test immediate [ES = 0.71] and delayed recall [ES = 0.65]). Cognitively impaired patients had a significantly lower estimated premorbid intelligence, worse physical and social functioning, and more distress at T2 compared to unimpaired patients.

CONCLUSION

Our findings indicate that cognitive impairment after systemic treatment occurs in a subset of BC patients. The predictive value of demographic and psychosocial factors in cognitive impairment should be further investigated in a larger sample of impaired patients.

Impact of Cognitive Function and Cancer Coping on Quality of Life among Women with Post-chemotherapy Breast Cancer

PURPOSE

This study was done to identify effects of cognitive function and cancer coping on quality of life among women with breast cancer treated with antineoplastic agents.

METHODS

The study was correlational research and participants were 145 women with breast cancer who had received antineoplastic agents. Data were collected from October to November, 2015 via online replies. Cognitive function was measured with the Functional Assessment of Cancer Therapy-Cognitive Function Version-3 (FACT-Cog), cancer coping, with the Korean Cancer Coping Questionnaire (K-CCQ), and quality of life with the Functional Assessment of Cancer Therapy-Breast Version-4 (FACT-B). Data were analyzed using descriptive statistics, t-test, ANOVA, Scheffé test, ANCOVA, Bonferroni test, partial correlation coefficient, and hierarchical multiple regression with SPSS 21.

RESULTS

Cognitive functions, total individual coping, and interpersonal coping explained 42% of quality of life. Cognitive function (β=.35, p<.001) was the best predictor of quality of life, followed by total individual coping (β=.34, p<.001), and interpersonal coping (β=.26, p<.001).

CONCLUSION

Results indicate that cognitive function and cancer coping are meaningful factors for quality of life among breast cancer survivors. Therefore when developing intervention programs for these women, content on cognitive function and coping skills as well as coping resources should be included.

Cognitive function in cancer survivors: analysis of the 1999-2002 National Health and Nutrition Examination Survey

PURPOSE

Cancer and its treatment may affect cognitive function through a number of direct and indirect pathways including inflammation, lipid metabolism, vascular damage, and changes in the blood-brain barrier. While short-term treatment-related cognitive changes are well recognized, only limited research is available in older, long-term survivors of cancer.

METHODS

Using NHANES data from 1999 to 2002, 408 cancer survivors and 2639 non-cancer participants aged 60 years old and above were identified. Cognitive function of these groups were compared using the Digit Symbol Substitution Test (DSST) and self-reported problems with memory or confusion.

RESULTS

After adjustment for covariates, cancer survivors scored, on average, 1.99 points lower on the DSST compared to non-cancer survivors (-1.99, 95 % CI -3.94, -0.05). Cancer survivors also had 17 % higher odds of self-reporting problems with memory or confusion (OR 1.17, 95 % CI 0.89, 1.53).

CONCLUSION

In this nationally representative sample of older US adults, cancer survivors had lower DSST scores than non-survivors and had more self-reported problems with memory or confusion.

Structure-function-behavior relationship in estrogen-induced synaptic plasticity

This article is part of a Special Issue "Estradiol and Cognition". In estrogen-induced synaptic plasticity, a correlation of structure, function and behavior in the hippocampus has been widely established. 17ß-estradiol has been shown to increase dendritic spine density on hippocampal neurons and is accompanied by enhanced long-term potentiation and improved performance of animals in hippocampus-dependent memory tests. After inhibition of aromatase, the final enzyme of estradiol synthesis, with letrozole we consistently found a strong and significant impairment of long-term potentiation (LTP) in female mice as early as after six hours of treatment. LTP impairment was followed by loss of hippocampal spine synapses in the hippocampal CA1 area. Interestingly, these effects were not found in male animals. In the Morris water maze test, chronic administration of letrozole did not alter spatial learning and memory in either female or male mice. In humans, analogous effects of estradiol on hippocampal morphology and physiology were observed using neuroimaging techniques. However, similar to our findings in mice, an effect of estradiol on memory performance has not been consistently observed.

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.

The long-term impact of oxaliplatin chemotherapy on rodent cognition and peripheral neuropathy

Chemotherapy treatment is associated with cognitive dysfunction in cancer survivors after treatment completion. The duration of these impairments is unclear. Therefore this paper aims to evaluate the lasting impact of varying doses of the chemotherapy oxaliplatin (OX) on cognition and peripheral neuropathy. In Experiment 1 rats were treated once a week for 3 weeks with either physiological saline (control) or 6 mg/kg OX i.p. and were assessed for peripheral neuropathy, using von Frey filaments, and cognitive function, using novel object and location recognition, up to 2 weeks after treatment completion. For Experiment 2 rats received 3 weekly i.p. injections of either physiological saline (control), 0.6 mg/kg, 2mg/kg or 6 mg/kg OX and assessed for peripheral neuropathy and cognitive function up to 11 months after treatment completion. Systemic OX treatment induced lasting effects on cognitive function at 11 months after treatment, and peripheral neuropathy at 1 month after treatment and these were dose dependent; higher doses of OX resulted in worse cognitive outcomes and more severe peripheral neuropathy.

Neuromarkers of fatigue and cognitive complaints following chemotherapy for breast cancer: a prospective fMRI investigation

The aim of this study is to use functional magnetic resonance imaging (fMRI) to prospectively examine pre-treatment predictors of post-treatment fatigue and cognitive dysfunction in women treated with adjuvant chemotherapy for breast cancer. Fatigue and cognitive dysfunction often co-occur in women treated for breast cancer. We hypothesized that pre-treatment factors, unrelated to chemotherapy per se, might increase vulnerability to post-treatment fatigue and cognitive dysfunction. Patients treated with (n = 28) or without chemotherapy (n = 37) and healthy controls (n = 32) were scanned coincident with pre- and one-month post-chemotherapy during a verbal working memory task (VWMT) and assessed for fatigue, worry, and cognitive dysfunction. fMRI activity measures in the frontoparietal executive network were used in multiple linear regression to predict post-treatment fatigue and cognitive function. The chemotherapy group reported greater pre-treatment fatigue than controls and showed compromised neural response, characterized by higher spatial variance in executive network activity, than the non-chemotherapy group. Also, the chemotherapy group reported greater post-treatment fatigue than the other groups. Linear regression indicated that pre-treatment spatial variance in executive network activation predicted post-treatment fatigue severity and cognitive complaints, while treatment group, age, hemoglobin, worry, and mean executive network activity levels did not predict these outcomes. Pre-treatment neural inefficiency (indexed by high spatial variance) in the executive network, which supports attention and working memory, was a better predictor of post-treatment cognitive and fatigue complaints than exposure to chemotherapy per se. This executive network compromise could be a pre-treatment neuromarker of risk, indicating patients most likely to benefit from early intervention for fatigue and cognitive dysfunction.

Prevalence, mechanisms, and management of cancer-related cognitive impairment

This review summarizes the current literature on cancer-related cognitive impairment (CRCI) with a focus on prevalence, mechanisms, and possible interventions for CRCI in those who receive adjuvant chemotherapy for non-central nervous system tumours and is primarily focused on breast cancer. CRCI is characterized as deficits in areas of cognition including memory, attention, concentration, and executive function. Development of CRCI can impair quality of life and impact treatment decisions. CRCI is highly prevalent; these problems can be detected in up to 30% of patients prior to chemotherapy, up to 75% of patients report some form of CRCI during treatment, and CRCI is still present in up to 35% of patients many years following completion of treatment. While the trajectory of CRCI is becoming better understood, the mechanisms underlying the development of CRCI are still obscure; however, host characteristics, immune dysfunction, neural toxicity, and genetics may play key roles in the development and trajectory of CRCI. Intervention research is limited, though strategies to maintain function are being studied with promising preliminary findings. This review highlights key research being conducted in these areas, both in patient populations and in animals, which will ultimately result in better understanding and effective treatments for CRCI.

Clearing the air: a review of our current understanding of "chemo fog"

An increasing number of cancer survivors has led to a greater interest in the long-term side effects of cancer treatments and their impact on quality of life. In particular, cognitive impairments have been frequently reported by cancer survivors as an adverse effect which they attribute to the neurotoxicity of chemotherapy and have dubbed "chemobrain" or "chemo fog." Research within the past 15-20 years has explored the many factors thought to contribute to cancer-related cognitive decline in an attempt to determine a potential cause. In spite of many confounding factors, there is growing evidence that the neurotoxicity of chemotherapy does contribute to cognitive changes. This review examines the evolution of "chemo fog" research with a look at methodological issues, the status of our current understanding, and suggestions for future research.

Reduced hippocampal volume and verbal memory performance associated with interleukin-6 and tumor necrosis factor-alpha levels in chemotherapy-treated breast cancer survivors

Many survivors of breast cancer show significant cognitive impairments, including memory deficits. Inflammation induced by chemotherapy may contribute to hippocampal changes that underlie these deficits. In this cross-sectional study, we measured bilateral hippocampal volumes from high-resolution magnetic resonance images in 42 chemotherapy-treated breast cancer survivors and 35 healthy female controls. Patients with breast cancer were, on average, 4.8 ± 3.4 years off-therapy. In a subset of these participants (20 breast cancer, 23 controls), we quantified serum cytokine levels. Left hippocampal volumes and memory performance were significantly reduced and interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNFα) concentrations were significantly elevated in the breast cancer group compared to controls. In the breast cancer group, lower left hippocampal volume was associated with higher levels of TNFα and lower levels of IL-6 with a significant interaction between these two cytokines suggesting a potential modulatory effect of IL-6 on TNFα. Verbal memory performance was associated with cytokine levels and left hippocampal volume in both groups. These findings provide evidence of altered hippocampal volume and verbal memory difficulties following breast cancer chemotherapy that may be mediated by TNFα and IL-6.

The effect of systemic chemotherapy on neurogenesis, plasticity and memory

Chemotherapy has been enormously successful in treating many forms of cancer and improving patient survival rates. With the increasing numbers of survivors, a number of cognitive side effects have become apparent. These have been called "chemobrain" or "chemofog" among patient groups, who describe the symptoms as a decline in memory, concentration and executive functions. Changes which, although subtle, can cause significant distress among patients and prevent a return to the quality of life experienced before treatment. This cognitive side effect of chemotherapy was not anticipated as it had been assumed that chemotherapy agents, administered systematically, could not cross the blood-brain barrier and that the brain was therefore protected from their action. It is now realised that low concentrations of many chemotherapy agents cross the blood-brain barrier and even those that are completely prevented from doing so, can induce the production of inflammatory cytokines in peripheral tissues which in turn can cross the blood-brain barrier and impact on the brain. A large number of patient studies have shown that cognitive decline is found in a proportion of patients treated with a variety of chemotherapy agents for different types of cancer. The deficits experienced by these patients can last for up to several years and have a deleterious effect on educational attainment and ability to return to work. Imaging studies of patients after systemic chemotherapy show that this treatment produces structural and functional changes in the brain some of which seem to persist even when the cognitive deficits have ceased. This suggests that, with time, brain plasticity may be able to compensate for the deleterious effects of chemotherapy treatment. A number of mechanisms have been suggested for the changes in brain structure and function found after chemotherapy. These include both central and peripheral inflammatory changes, demyelination of white matter tracts, a reduction in stem cell proliferation in both the hippocampal neurogenic region and by oligodendrocyte precursors as well as changes in hormonal or growth factor levels. A number of possible treatments have been suggested which range from pharmacological interventions to cognitive behavioural therapies. Some of these have only been tested in animal models while others have produced varying degrees of improvement in patient populations. Currently, there is no recognised treatment and a greater understanding of the causes of the cognitive decline experienced after chemotherapy will be key to finding ways of preventing or treating the effects of chemobrain.

Brain vulnerability to chemotherapy toxicities

Chemotherapy-induced cognitive changes have been an increasing concern among cancer survivors. By using adjuvant treatment for breast cancer as the prototype, this manuscript reviews research from neuropsychological, imaging, genetic, and animal model studies that have examined the clinical presentation and potential mechanisms for cognitive changes associated with exposure to chemotherapy. An impressive body of research supports the hypothesis that a subgroup of patients is vulnerable to post-treatment cognitive changes, although not exclusively related to chemotherapy. Further, imaging and animal model studies provide accumulating evidence of putative mechanisms for chemotherapy-induced cognitive change. Models of aging are also reviewed in support of the proposal that cognitive changes associated with cancer and cancer treatments can be viewed in the context of factors that affect the trajectory of normal aging.

Cancer- and cancer treatment-associated cognitive change: an update on the state of the science

Cognitive changes associated with cancer and cancer treatments have become an increasing concern. Using breast cancer as the prototype, we reviewed the research from neuropsychological, imaging, genetic, and animal studies that have examined pre- and post-treatment cognitive change. An impressive body of research supports the contention that a subgroup of patients is vulnerable to post-treatment cognitive problems. We also propose that models of aging may be a useful conceptual framework for guiding research in this area and suggest that a useful perspective may be viewing cognitive change in patients with cancer within the context of factors that influence the trajectory of normal aging.