Longitudinal assessment of chemotherapy-induced structural changes in cerebral white matter and its correlation with impaired cognitive functioning

Depressive symptoms and cognitive deficits in a cancer patient submitted to chemotherapy with 5-Fluoracil: a case report

Cognitive deficits in cancer patients can be related to depression, anxiety, and the side effects of treatments such as fatigue. In this case report, we described an elderly patient with rectal adenocarcinoma, which presented depressive symptoms and memory complaints after treatment with 5-Fluoracil and Leucovorin. Depressive symptoms improved after two months but cognitive and functional impairment worsened suggesting the diagnosis of mild dementia. Structural and functional brain changes were seen on neuroimaging exams. Rivastigmine was introduced up to 12 mg/day, and after a one-year follow up the patient remained stable. Cognitive deficits can be a consequence of cancer therapies and a protocol to investigate deficits cognitive could be useful to the diferential diagnosis and management of elderly cancer patients submitted to chemotherapy.

Default mode network connectivity distinguishes chemotherapy-treated breast cancer survivors from controls

Breast cancer (BC) chemotherapy is associated with cognitive changes including persistent deficits in some individuals. We tested the accuracy of default mode network (DMN) resting state functional connectivity patterns in discriminating chemotherapy treated (C+) from non-chemotherapy (C-) treated BC survivors and healthy controls (HC). We also examined the relationship between DMN connectivity patterns and cognitive function. Multivariate pattern analysis was used to classify 30 C+, 27 C-, and 24 HC, which showed significant accuracy for discriminating C+ from C- (91.23%, P < 0.0001) and C+ from HC (90.74%, P < 0.0001). The C- group did not differ significantly from HC (47.06%, P = 0.60). Lower subjective memory function was correlated (P < 0.002) with greater hyperplane distance (distance from the linear decision function that optimally separates the groups). Disrupted DMN connectivity may help explain long-term cognitive difficulties following BC chemotherapy.

Late effects of adjuvant chemotherapy for adult onset non-CNS cancer; cognitive impairment, brain structure and risk of dementia

Few studies have investigated the late (i.e. ≥ 5 years post-treatment) effects of chemotherapy for non-central nervous system (non-CNS) cancer on the brain. Here we discuss the studies that have investigated the late effects of adjuvant chemotherapy for non-CNS cancer on cognitive function (n=6); brain structure and function (n=5); and incidence of dementia (n=4). The neuropsychological studies showed long-term adverse cognitive problems in chemotherapy-exposed breast cancer survivors. This is in line with results from neuroimaging studies that report long-term brain structural alterations after chemotherapy. The studies exploring the association between chemotherapy and the incidence of dementia were contradictive and showed no clear relationship between the two phenomena. Although several methodological issues limit the validity and interpretation of some of the results of these studies, they suggest that chemotherapy is associated with subtle, yet long-lasting cognitive deficits, possibly related to brain structural and functional differences, but as yet not with an increased risk of dementia.

Long-term cognitive function, neuroimaging, and quality of life in primary CNS lymphoma

OBJECTIVE

To describe and correlate neurotoxicity indicators in long-term primary CNS lymphoma (PCNSL) survivors who were treated with high-dose methotrexate-based regimens with or without whole-brain radiotherapy (WBRT).

METHODS

Eighty PCNSL survivors from 4 treatment groups (1 with WBRT and 3 without WBRT) who were a minimum of 2 years after diagnosis and in complete remission underwent prospective neuropsychological, quality-of-life (QOL), and brain MRI evaluation. Clinical characteristics were compared among treatments by using the χ(2) test and analysis of variance. The association among neuroimaging, neuropsychological, and QOL outcomes was assessed by using the Pearson correlation coefficient.

RESULTS

The median interval from diagnosis to evaluation was 5.5 years (minimum, 2 years; maximum, 26 years). Survivors treated with WBRT had lower mean scores in attention/executive function (p = 0.0011), motor skills (p = 0.0023), and neuropsychological composite score (p = 0.0051) compared with those treated without WBRT. Verbal memory was better in survivors with longer intervals from diagnosis to evaluation (p = 0.0045). On brain imaging, mean areas of total T2 abnormalities were different among treatments (p = 0.0006). Total T2 abnormalities after WBRT were more than twice the mean of any non-WBRT group and were associated with poorer neuropsychological and QOL outcomes.

CONCLUSIONS

Our results suggest that in patients treated for PCNSL achieving complete remission and surviving at least 2 years, the addition of WBRT to methotrexate-based chemotherapy increases the risk of treatment-related neurotoxicity. Verbal memory may improve over time.

CLASSIFICATION OF EVIDENCE

This study provides Class III evidence that in patients treated for PCNSL achieving complete remission and surviving at least 2 years, the addition of WBRT to methotrexate-based chemotherapy increases the risk of treatment-related neurotoxicity.

Cognitive training for improving executive function in chemotherapy-treated breast cancer survivors

BACKGROUND

A majority of breast cancer (BC) survivors, particularly those treated with chemotherapy, experience long-term cognitive deficits that significantly reduce quality of life. Among the cognitive domains most commonly affected include executive functions (EF), such as working memory, cognitive flexibility, multitasking, planning, and attention. Previous studies in other populations have shown that cognitive training, a behavioral method for treating cognitive deficits, can result in significant improvements in a number of cognitive skills, including EF.

MATERIALS AND METHODS

In this study, we conducted a randomized controlled trial to investigate the feasibility and preliminary effectiveness of a novel, online EF training program in long-term BC survivors. A total of 41 BC survivors (21 active, 20 wait list) completed the 48 session training program over 12 weeks. The participants were, on average, 6 years after therapy.

RESULTS

Cognitive training led to significant improvements in cognitive flexibility, verbal fluency and processing speed, with marginally significant downstream improvements in verbal memory as assessed via standardized measures. Self-ratings of EF skills, including planning, organizing, and task monitoring, also were improved in the active group compared with the wait list group.

CONCLUSIONS

Our findings suggest that EF skills may be improved even in long-term survivors by using a computerized, home-based intervention program. These improvements may potentially include subjective EF skills, which suggest a transfer of the training program to real-world behaviors.

Cognitive complaints after breast cancer treatments: examining the relationship with neuropsychological test performance

BACKGROUND

Cognitive complaints are reported frequently after breast cancer treatments. Their association with neuropsychological (NP) test performance is not well-established.

METHODS

Early-stage, posttreatment breast cancer patients were enrolled in a prospective, longitudinal, cohort study prior to starting endocrine therapy. Evaluation included an NP test battery and self-report questionnaires assessing symptoms, including cognitive complaints. Multivariable regression models assessed associations among cognitive complaints, mood, treatment exposures, and NP test performance.

RESULTS

One hundred eighty-nine breast cancer patients, aged 21-65 years, completed the evaluation; 23.3% endorsed higher memory complaints and 19.0% reported higher executive function complaints (>1 SD above the mean for healthy control sample). Regression modeling demonstrated a statistically significant association of higher memory complaints with combined chemotherapy and radiation treatments (P = .01), poorer NP verbal memory performance (P = .02), and higher depressive symptoms (P < .001), controlling for age and IQ. For executive functioning complaints, multivariable modeling controlling for age, IQ, and other confounds demonstrated statistically significant associations with better NP visual memory performance (P = .03) and higher depressive symptoms (P < .001), whereas combined chemotherapy and radiation treatment (P = .05) approached statistical significance.

CONCLUSIONS

About one in five post-adjuvant treatment breast cancer patients had elevated memory and/or executive function complaints that were statistically significantly associated with domain-specific NP test performances and depressive symptoms; combined chemotherapy and radiation treatment was also statistically significantly associated with memory complaints. These results and other emerging studies suggest that subjective cognitive complaints in part reflect objective NP performance, although their etiology and biology appear to be multifactorial, motivating further transdisciplinary research.

The Effect of EEG Biofeedback on Reducing Postcancer Cognitive Impairment

Background and hypotheses. Postcancer cognitive impairment (PCCI) is observed in a substantial number of breast cancer survivors, persisting for as long as 20 years in some subgroups. Although compensatory strategies are frequently suggested, no restorative interventions have yet been identified. This study examined the feasibility of EEG biofeedback (“neurofeedback”) and its potential effectiveness in reducing PCCI as well as the fatigue, sleep disturbance, and psychological symptoms that frequently accompany PCCI. Study design. This was a 6-month prospective study with a waitlist control period followed by an active intervention. Participants were female breast cancer survivors (n = 23), 6 to 60 months postchemotherapy, with self-reported cognitive impairment. Methods. Four self-report outcome measures (Functional Assessment of Cancer Therapy–Cognitive Function [FACT-Cog], Functional Assessment of Chronic Illness Therapy–Fatigue [FACIT-Fatigue], Pittsburgh Sleep Quality Index [PSQI], and Brief Symptom Inventory [BSI]-18) were administered 3 times during a 10-week waitlist control period, 3 times during a 10-week (20-session) neurofeedback training regimen, and once at 4 weeks postneurofeedback. Results. All 23 participants completed the study, demonstrating the feasibility of EEG biofeedback in this population. Initially, the sample demonstrated significant dysfunction on all measures compared with general population norms. Repeated-measures ANOVAs revealed strongly significant improvements ( P < .001) on all 4 cognitive measures (perceived cognitive impairment, comments from others, perceived cognitive abilities, and impact on quality of life [QOL]), the fatigue scale, and the 4 psychological scales (somatization, depression, anxiety and global severity index) as well as on 3 of 8 sleep scales (quality, daytime dysfunction, and global). Two of the other sleep scales (latency and disturbance) were significant at P < .01, and 1 (use of medication) at P < .05; 2 were not significant. Improvements were generally linear across the course of training, and were maintained at the follow-up testing. At the follow-up testing, the sample no longer differed significantly from normative populations on 3 of the 4 FACT-Cog measures (impairment, impact on QOL, and comments), FACIT-Fatigue, PSQI sleep quality and habitual efficiency, or any of the BSI-18 measures of psychological disturbance. Conclusions. Data from this limited study suggest that EEG biofeedback has potential for reducing the negative cognitive and emotional sequelae of cancer treatment as well as improving fatigue and sleep patterns.

Cognitive impairments and cancer chemotherapy: translational research at a crossroads

Cancer chemotherapy is often associated with cognitive deficits which may remain after the treatment has ended. As more people survive cancer, concern is increasing about the impact of these problems with memory and executive function when they return to everyday life. When chemotherapeutic drugs are administered to healthy animals in dosing regimens modeling those used in humans, cognitive deficits also occur, and these preclinical studies can provide information about the biological mechanisms by which the cancer fighting drugs affect the brain. Evidence from animal studies points to damage to hippocampus, particularly a disruption of neurogenesis, whereas human studies emphasize cognitive deficits associated with impairments in frontal cortical function. This discrepancy may be due more to the tasks selected by researchers, and the choice of biochemical endpoints than inherently different effects of chemotherapy in humans and rodents. These differences in approach must be reconciled if common underlying mechanisms are to be identified, with the hope of leading to novel drug or non-pharmacological treatments. This may be achieved by broadening the scope of human and animal studies, and by looking outside the topic of chemotherapy-induced cancer deficits to learn from the advances being made by studying the effects of stress and somatic disease on brain function, and the cognitive impairments now recognized to result from a wide range of mental and physical illnesses.

Association between chemotherapy and cognitive impairments in a large cohort of patients with colorectal cancer

No population-based study has been conducted on the relationship between chemotherapy and the risk of cognitive impairments in patients with colorectal cancer. This study aimed to determine this association in a large population-based cohort of patients. We studied 72,374 men and women who were diagnosed with stages I-III colorectal cancer at age ≥ 65 years from 1991 through 2002 from 16 regions in the Surveillance, Epidemiology and End Results program who were free of cognitive impairments at baseline with up to 17 years of follow-up and also studied 15,921 matched cohorts based on the propensity of receiving chemotherapy. The cumulative incidence of drug-induced dementia at 5 years was 16.2 cases per 1,000 persons for the chemotherapy group and 12.4 cases per 1,000 persons for the no chemotherapy group. Overall, patients who received chemotherapy were 24% significantly more likely to develop drug-induced dementia compared to those without chemotherapy after adjusting for patient and tumor characteristics (hazard ratio 1.24, 95% confidence interval 1.05-1.47). The significantly increased risk was only observed in those without mood disorder who received chemotherapy in the entire cohort (1.26, 1.06-1.50) and in the matched cohort (1.29, 1.04-1.59). The risk of developing Alzheimer's disease, vascular dementia or other dementias was significantly lower in patients receiving chemotherapy compared to those without chemotherapy regardless of mood disorder status. In conclusion, there was a significant association between chemotherapy and the risk of developing drug-induced dementia in patients with colorectal cancer without mood disorder, but chemotherapy was associated with a decreased risk of other dementias.

Opening up the window into "chemobrain": a neuroimaging review

As more chemotherapy-treated cancer patients are reaching survivorship, side-effects such as cognitive impairment warrant research attention. The advent of neuroimaging has helped uncover a neural basis for these deficits. This paper offers a review of neuroimaging investigations in chemotherapy-treated adult cancer patients, discussing the benefits and limitations of each technique and study design. Additionally, despite the assumption given by the chemobrain label that chemotherapy is the only causative agent of these deficits, other factors will be considered. Suggestions are made on how to more comprehensively study these cognitive changes using imaging techniques, thereby promoting generalizability of the results to clinical applications. Continued investigations may yield better long-term quality of life outcomes by supporting patients' self-reports, and revealing brain regions being affected by chemotherapy.

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.

Does tumor necrosis factor-alpha (TNF-α) play a role in post-chemotherapy cerebral dysfunction?

Post-chemotherapy treated cancer patients frequently report cognitive difficulties. The biology of this phenomenon is poorly understood, with uncertainty about possible direct toxic effects on the brain, secondary effects from systemic inflammation, host factors/genetic predisposition to cognitive complaints, or hormonal changes influencing cognitive function. To elucidate possible mechanisms associated with post-treatment cognitive dysfunction among breast cancer survivors, in 2007 we established a prospective, longitudinal, observational cohort study of early stage breast cancer patients, recruited at the end of initial treatments (primary treatment exposure included surgery, ± radiation, ± chemotherapy), and prior to the initiation of adjuvant endocrine therapy. We assessed cognitive complaints, neuropsychological (NP) test performance, markers of inflammation, and brain imaging at baseline, 6 months and 12 months after enrollment. In this analysis of data from the first 93 patients enrolled in the cohort study, we focus on the relationship of circulating levels of proinflammatory cytokines to cerebral functioning and chemotherapy exposure. Among the proinflammatory cytokines tested (IL-1 ra, sTNF-RII, CRP, and IL-6) at baseline, only sTNF-RII was increased among chemotherapy exposed patients, with a significant decline in the year after treatment (p=0.003). Higher baseline sTNF-RII in chemotherapy patients was significantly associated with increased memory complaints. In chemotherapy exposed patients, the longitudinal decline in sTNF-RII was significantly correlated with fewer memory complaints over 12 months (r=-0.34, p=0.04). Higher baseline sTNF-RII was also associated with relatively diminished brain metabolism in the inferior frontal cortex (r=-0.55, p=0.02), as well as relatively increased inferior frontal metabolism after 1 year, in chemotherapy-exposed subjects. These preliminary findings suggest that post-chemotherapy increases in TNF-α may be playing an important role in the manifestations of cognitive complaints in breast cancer survivors.

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.

Breast cancer survivorship symptom management: current perspective and future development

Increasing numbers and longevity of cancer survivors has furthered our insight into the factors affecting their health outcomes, suggesting that multiple factors play a role (e.g., effects of cancer treatments and health behaviors). Emotional and physical symptoms may not always receive sufficient attention. In this short narrative review highlighting recent literature, we describe the most common physical and emotional symptoms of breast cancer survivors aged 50 years and older and outline a multidisciplinary symptom management approach, regardless of symptom etiology.

Alterations in brain structure and function in breast cancer survivors: effect of post-chemotherapy interval and relation to oxidative DNA damage

Neuroimaging studies have begun to uncover the neural substrates of cancer and treatment-related cognitive dysfunction, but the time course of these changes in the years following chemotherapy is unclear. This study analyzed multimodality 3T MRI scans to examine the structural and functional effects of chemotherapy and post-chemotherapy interval (PCI) in a cohort of breast cancer survivors (BCS; n = 24; PCI mean 6, range 3-10 y) relative to age- and education-matched healthy controls (HC; n = 23). Assessments included voxel-based morphometry for gray matter density (GMD) and fMRI for activation profile during a 3-back working memory task. The relationships between brain regions associated with PCI and neuropsychological performance, self-reported cognition, and oxidative and direct DNA damage as measured in peripheral lymphocytes were assessed in secondary analyses. PCI was positively associated with GMD and activation on fMRI in the right anterior frontal region (Brodmann Areas 9 and 10) independent of participant age. GMD in this region was also positively correlated with global neuropsychological function. Memory dysfunction, cognitive complaints, and oxidative DNA damages were increased in BCS compared with HC. Imaging results indicated lower fMRI activation in several regions in the BCS group. BCS also had lower GMD than HC in several regions, and in these regions, GMD was inversely related to oxidative DNA damage and learning and memory neuropsychological domain scores. This is the first study to show structural and functional effects of PCI and to relate oxidative DNA damage to brain alterations in BCS. The relationship between neuroimaging and cognitive function indicates the potential clinical relevance of these findings. The relationship with oxidative DNA damage provides a mechanistic clue warranting further investigation.

Global and focal white matter integrity in breast cancer survivors 20 years after adjuvant chemotherapy

OBJECTIVES

To date, only four small studies have investigated the effects of adjuvant chemotherapy for breast cancer on the microstructure of cerebral white matter with magnetic resonance imaging (MRI). These studies, which were conducted shortly up to 10 years post-treatment, showed that chemotherapy is associated with focal loss of microstructural white matter integrity. We investigated the long-term effect of chemotherapy on white matter microstructural integrity by comparing the brains of chemotherapy-exposed breast cancer survivors to those of a population-based sample of women without a history of cancer.

EXPERIMENTAL DESIGN

Diffusion tensor imaging (DTI) MRI (1.5 T) was performed in 187 CMF (cyclophosphamide, methotrexate, and 5-flourouracil) chemotherapy-exposed breast cancer survivors, mean age 64.2 (sd = 6.5) years, who had been diagnosed with cancer on average 21.2 (sd = 4.4) years before, and 374 age-matched cancer-free reference subjects from a population-based cohort study. Outcome measures were whole-brain microstructural integrity as measured by fractional anisotropy and mean/axial/radial diffusivity and focal white matter integrity, which was analyzed with tract-based spatial statistics. All analyses were adjusted for age, cardiovascular risk factors, education, and symptoms of depression.

PRINCIPAL OBSERVATIONS

No significant group differences were observed in white matter integrity. However, within the breast cancer survivors, time since treatment was inversely associated with lower global and focal white matter integrity.

CONCLUSIONS

This cross-sectional study suggests that among chemotherapy-exposed breast cancer survivors white matter microstructural integrity deteriorates with accumulating time since treatment. This warrants further investigation.

Why, After Chemotherapy, is it Necessary to Assess Memory Using Translational Testing?

As the number of cancer survivors rises, so does the importance of understanding what happens post-chemotherapy. The evidence is clear that chemotherapy affects not only cancer cells, but also healthy cells including neurons, leading to long-term cognitive dysfunction in a large portion of survivors. In order to understand the mechanism of action and in the hope of reducing the potential neurocognitive side effects of chemotherapy, pre-clinical testing should be used more effectively. However, the field is lacking translation from clinical studies to animal models. Spatial learning and memory paradigms based on the water maze, the most commonly used rodent model, are available for translational testing in humans and could overcome this weakness. There is an overwhelming need in the field to understand whether the water maze is an adequate model for post-chemotherapy impairments or whether other paradigms should be used. This is of great importance for the understanding of the mechanisms, side effects of new drugs, appropriate pharmacotherapy, and confounding factors related to chemotherapy treatment regiments. This review is very important to both basic scientists and clinicians determining how translational paradigms are critical to future cancer research, as well as what type of paradigms are appropriate in our technically advancing society.

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.

Cognitive effects of chemotherapy in breast cancer patients: a dose-response study

OBJECTIVE

The purpose of this study was to determine if cognition progressively worsens with cumulative chemotherapy exposure. We reasoned that the demonstration of such a 'dose-response' relationship would help to establish whether cognitive changes are caused by neurotoxic effects of chemotherapy or whether they are due to other confounding factors such as mood and pre-treatment differences in cognition.

METHODS

Sixty women with early stage breast cancer, aged 65 years or younger with no previous history of cancer or chemotherapy, were matched to 60 healthy women on age and education. Neuropsychological assessment was conducted after surgery but prior to commencing chemotherapy and then again following each chemotherapy cycle in patients and at yoked intervals in healthy controls. We used multilevel modeling to assess change over time in an overall cognitive summary score as well as domain-specific cognitive scores.

RESULTS

After controlling for baseline performance, age, education, and mood, the chemotherapy group showed a significant progressive decline over time relative to a matched healthy control group in an overall cognitive summary score, as well as in working memory, processing speed, verbal memory, and visual memory scores. A linear model best fit the trajectory of cognitive change over the course of treatment in the chemotherapy group supporting a dose-response hypothesis.

CONCLUSIONS

These results are in keeping with a dose-response relationship and provide the most compelling clinical evidence to date that cognitive decline is caused by chemotherapy exposure.

Effects of androgen deprivation on brain function in prostate cancer patients - a prospective observational cohort analysis

Background

Despite a lack of consensus regarding effectiveness, androgen deprivation therapy (ADT) is a common treatment for non-metastatic, low-risk prostate cancer. To examine a particular clinical concern regarding the possible impact of ADT on cognition, the current study combined neuropsychological testing with functional magnetic resonance imaging (fMRI) to assess both brain activation during cognitive performance as well as the integrity of brain connectivity.

Methods

In a prospective observational cohort analysis of men with non-metastatic prostate cancer at a Veterans Affairs medical center, patients receiving ADT were compared with patients not receiving ADT at baseline and at 6 months. Assessments included fMRI, the N-back task (for working memory), the stop-signal task (for cognitive control), and a quality of life questionnaire.

Results

Among 36 patients enrolled (18 in each group), 30 completed study evaluations (15 in each group); 5 withdrew participation and 1 died. Results for the N-back task, stop-signal task, and quality of life were similar at 6 months vs. baseline in each group. In contrast, statistically significant associations were found between ADT use (vs. non use) and decreased medial prefrontal cortical activation during cognitive control, as well as decreased connectivity between the medial prefrontal cortex and other regions involved with cognitive control.

Conclusions

Although ADT for 6 months did not affect selected tests of cognitive function, brain activations during cognitive control and functional brain connectivity were impaired on fMRI. The long-term clinical implications of these changes are not known and warrant future study.

Lack of a chemobrain effect for adjuvant FOLFOX chemotherapy in colon cancer patients. A pilot study

PURPOSE

Chemotherapy improves the survival rate of stage III colon cancer patients. The combination of oxaliplatin, 5-fluorouracil, and leucovorin (the FOLFOX4 regimen) has emerged as the standard of care. This prospective study evaluates potential alterations in cognitive function in FOLFOX4-treated patients.

METHODS

We evaluated 57 consecutive colorectal cancer patients who received adjuvant chemotherapy with FOLFOX4. Patients underwent a complete battery of neuropsychological tests at three different times: before (T0), at the end (T1), and 6 months after treatment (T2).

RESULTS

We have analyzed cognitive impairment (Mini Mental State Examination, MMSE), visuo-spatial memory (Clock Drawing Test, CDT, Rey Complex Figure, copy and recall), information processing speed (Trial Making Test-A, TMT-A, and Trial Making Test-B, TMT-B), verbal memory (Rey Auditory Verbal Learning Test, call and recall), emotional distress (Psychological Distress Inventory, PDI), anxiety (State and Trait Anxiety Inventory, STAI-Y1 and Y2), and depression (Beck Depression Inventory, BDI). Then we have calculated, for each test and for each interval of time, mean ± standard deviation for the mean. In a subsequent phase, we tested the significance of different results through the ANOVA analysis for repeated measures. In this case, we could not find any statistically significant modification in cognitive function, but we could notice an improvement in emotional performance, anxiety and depression a short time after chemotherapy administration.

CONCLUSIONS

We found no effect on cognitive function related to chemotherapy, the only little modification is about some emotional performance during chemotherapy. These findings may be explained by the central role of the psychological adaptation process, which occurs during the period from diagnosis to completion of treatment and is characterized by anxiety and adjustment depression. Our results seem to rule out any significant cognitive impairment due to adjuvant FOLFOX4 chemotherapy in colon cancer patients.

Altered resting state functional brain network topology in chemotherapy-treated breast cancer survivors

Many women with breast cancer, especially those treated with chemotherapy, experience cognitive decline due in part to neurotoxic brain injury. Recent neuroimaging studies suggest widespread brain structural abnormalities pointing to disruption of large-scale brain networks. We applied resting state functional magnetic resonance imaging and graph theoretical analysis to examine the connectome in breast cancer survivors treated with chemotherapy relative to healthy comparison women. Compared to healthy females, the breast cancer group displayed altered global brain network organization characterized by significantly decreased global clustering as well as disrupted regional network characteristics in frontal, striatal and temporal areas. Breast cancer survivors also showed significantly increased self-report of executive function and memory difficulties compared to healthy females. These results suggest that topological organization of both global and regional brain network properties may be disrupted following breast cancer and chemotherapy. This pattern of altered network organization is believed to result in reduced efficiency of parallel information transfer. This is the first report of alterations in large-scale functional brain networks in this population and contributes novel information regarding the neurobiologic mechanisms underlying breast cancer-related cognitive impairment.

Alterations in brain structure and function after chemotherapy for cancer

The majority of cancer patients treated with chemotherapy complain of fatigue and/or cognitive dysfunction. Although many patients experience improvement shortly after completion of treatment, a substantial number of patients may continue to be symptomatic for years or even decades after their last dose of chemotherapy. This review focuses on the scope of postchemotherapy cognitive dysfunction, spotlights recent studies that investigate this problem in the short- and long-term, examines neuroimaging studies that document regional cerebral alterations observed after chemotherapy, discusses candidate mechanisms and treatments and finally comments on challenges in the field.

Alterations in brain activation during working memory processing associated with breast cancer and treatment: a prospective functional magnetic resonance imaging study

PURPOSE

To prospectively examine alterations in working memory (WM) -associated brain activation related to breast cancer and treatment by using functional magnetic resonance imaging.

PATIENTS AND METHODS

Patients treated with chemotherapy (CTx+; n = 16) or without chemotherapy (CTx-; n = 12) and healthy controls (n = 15) were scanned during an n-back task at baseline (after surgery but before radiation, chemotherapy, and/or antiestrogen treatment), 1 month after completion of chemotherapy (M1), and 1 year later (Y1), or at yoked intervals for CTx- and controls. SPM5 was used for all image analyses, which included cross-sectional between-group and group-by-time interaction and longitudinal within-group analyses, all using a statistical threshold of 0.001.

RESULTS

At baseline, patients with cancer showed increased bifrontal and decreased left parietal activation compared with controls. At M1, both cancer groups showed decreased frontal hyperactivation compared with controls, with increased hyperactivation at Y1. These cross-sectional findings were confirmed by group-by-time interaction analyses, which showed frontal activation decreases from baseline to M1 in patients compared with controls. Within-group analyses showed different patterns of longitudinal activation change by treatment group (CTx+ or CTx-), with prominent alterations in the frontal lobes bilaterally.

CONCLUSION

Significant frontal lobe hyperactivation to support WM was found in patients with breast cancer. Superimposed on this background, patients showed decreased frontal activation at M1, with partial return to the previously abnormal baseline at Y1. These functional changes correspond to frontal lobe regions where we previously reported structural changes in this cohort and provide prospective, longitudinal data that further elucidate mechanisms underlying cognitive effects related to breast cancer and its treatment.

Neuropsychological performance in survivors of breast cancer more than 20 years after adjuvant chemotherapy

PURPOSE

Adjuvant chemotherapy for breast cancer can have adverse effects on cognition shortly after administration. Whether chemotherapy has any long-term effects on cognition is largely unknown, yet it becomes increasingly relevant because of the widespread use of chemotherapy for early-stage breast cancer and the improved survival. We investigated whether cyclophosphamide, methotrexate, and fluorouracil (CMF) chemotherapy for breast cancer is associated with worse cognitive performance more than 20 years after treatment.

PATIENTS AND METHODS

This case-cohort study compared the cognitive performance of patients with breast cancer who had a history of adjuvant CMF chemotherapy treatment (six cycles; average time since treatment, 21 years; n = 196) to that of a population-based sample of women never diagnosed with cancer (n = 1,509). Participants were between 50 and 80 years of age. Exclusion criteria were ever use of adjuvant endocrine therapy, secondary malignancy, recurrence, and/or metastasis.

RESULTS

The women exposed to chemotherapy performed significantly worse than the reference group on cognitive tests of immediate (P = .015) and delayed verbal memory (P = .002), processing speed (P < .001), executive functioning (P = .013), and psychomotor speed (P = .001). They experienced fewer symptoms of depression (P < .001), yet had significantly more memory complaints on two of three measures that could not be explained by cognitive test performance.

CONCLUSION

Survivors of breast cancer treated with adjuvant CMF chemotherapy more than 20 years ago perform worse, on average, than random population controls on neuropsychological tests. The pattern of cognitive problems is largely similar to that observed in patients shortly after cessation of chemotherapy. This study suggests that cognitive deficits following breast cancer diagnosis and subsequent CMF chemotherapy can be long lasting.