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

Course and Predictors of Cognitive Function in Patients With Prostate Cancer Receiving Androgen-Deprivation Therapy: A Controlled Comparison

PURPOSE

Men receiving androgen-deprivation therapy (ADT) for prostate cancer may be at risk for cognitive impairment; however, evidence is mixed in the existing literature. Our study examined the impact of ADT on impaired cognitive performance and explored potential demographic and genetic predictors of impaired performance.

PATIENTS AND METHODS

Patients with prostate cancer were assessed before or within 21 days of starting ADT (n = 58) and 6 and 12 months later. Age- and education-matched patients with prostate cancer treated with prostatectomy only (n = 84) and men without prostate cancer (n = 88) were assessed at similar intervals. Participants provided baseline blood samples for genotyping. Mean-level cognitive performance was compared using mixed models; cognitive impairment was compared using generalized estimating equations.

RESULTS

ADT recipients demonstrated higher rates of impaired cognitive performance over time relative to all controls (P = .01). Groups did not differ at baseline (P > .05); however, ADT recipients were more likely to demonstrate impaired performance within 6 and 12 months (P for both comparisons < .05). Baseline age, cognitive reserve, depressive symptoms, fatigue, and hot flash interference did not moderate the impact of ADT on impaired cognitive performance (P for all comparisons ≥ .09). In exploratory genetic analyses, GNB3 single-nucleotide polymorphism rs1047776 was associated with increased rates of impaired performance over time in the ADT group (P < .001).

CONCLUSION

Men treated with ADT were more likely to demonstrate impaired cognitive performance within 6 months after starting ADT relative to matched controls and to continue to do so within 12 months after starting ADT. If confirmed, findings may have implications for patient education regarding the risks and benefits of ADT.

Doxorubicin and cyclophosphamide induce cognitive dysfunction and activate the ERK and AKT signaling pathways

Chemotherapy is associated with long-term cognitive deficits in breast cancer survivors. Studies suggest that these impairments result in the loss of cognitive reserve and/or induce a premature aging of the brain. This study has been aimed to determine the potential underlying mechanisms that induce cognitive impairments by chemotherapeutic agents commonly used in breast cancer. Intact and ovariectomized (OVX) female rats were treated intravenously with either saline or a combination of cyclophosphamide (40 mg/kg) and doxorubicin (4 mg/kg). All subjects were tested for anxiety, locomotor activity, working, visual and spatial memory consecutively. Although anxiety and visual memory were not affected, chemotherapy significantly decreased locomotor activity and impaired working and spatial memory in female rats, independent of their hormonal status. The cognitive deficits observed are hippocampal dependent. Therefore, as a first step to identity the potential signaling pathways involved in this cognitive dysfunction, the protein levels of extracellular signal-regulated kinase 1/2 (Erk1/2), Akt (neuroprotectant) BDNF and (structural protein) PSD95 in hippocampal lysates were measured. Erk1/2 and Akt pathways are known to modulate synaptic plasticity, neuronal survival, aging and cancer. We found an increased activation of Erk1/2 and Akt as well as an increase in the protein levels of PSD95 in OVX female rodents. However, OVX females had a higher overall BDNF level, independent of chemotherapy. These studies provide additional evidence that commonly used chemotherapeutic agents affect cognitive function and impact synaptic plasticity/aging molecules which may be part of the underlying biology explaining cognitive change and can be potential therapeutic targets.

Chemotherapy, cognitive impairment and hippocampal toxicity

Cancer therapies can be associated with significant central nervous system (CNS) toxicity. While radiation-induced brain damage has been long recognized both in pediatric and adult cancer patients, CNS toxicity from chemotherapy has only recently been acknowledged. Clinical studies suggest that the most frequent neurotoxic adverse effects associated with chemotherapy include memory and learning deficits, alterations of attention, concentration, processing speed and executive function. Preclinical studies have started to shed light on how chemotherapy targets the CNS both on cellular and molecular levels to disrupt neural function and brain plasticity. Potential mechanisms include direct cellular toxicity, alterations in cellular metabolism, oxidative stress, and induction of pro-inflammatory processes with subsequent disruption of normal cellular and neurological function. Damage to neural progenitor cell populations within germinal zones of the adult CNS has been identified as one of the key mechanisms by which chemotherapy might exert long-lasting and progressive neurotoxic effects. Based on the important role of the hippocampus for maintenance of brain plasticity throughout life, several experimental studies have focused on the study of chemotherapy effects on hippocampal neurogenesis and associated learning and memory. An increasing body of literature from both animal studies and neuroimaging studies in cancer patients suggests a possible relationship between chemotherapy induced hippocampal damage and the spectrum of neurocognitive deficits and mood alterations observed in cancer patients. This review aims to briefly summarize current preclinical and neuroimaging studies that are providing a potential link between the neurotoxic effects of chemotherapy and hippocampal dysfunction, highlighting challenges and future directions in this field of investigation.

Cortical surface area and thickness in adult survivors of pediatric acute lymphoblastic leukemia

BACKGROUND

Advances in the treatment of acute lymphoblastic leukemia (ALL) have led to great improvements in survival rates and outcomes, but there is concern about cognitive late effects. We aimed to determine whether ALL survivors have smaller cortical surface area and/or thickness, and test whether this is related to disease and treatment variables and self-reported executive functioning in everyday life.

PROCEDURE

Magnetic resonance imaging (MRI) scans from 130 adult long-term survivors of childhood ALL (age: 18-46 years; age at diagnosis: 0-16 years; years since diagnosis: 7-40) and 130 healthy controls were assessed to estimate and compare regional cortical surface area and thickness. Information on disease and treatment factors were obtained from patients' records, and executive functioning in survivors was measured using a validated questionnaire (BRIEF-A).

RESULTS

Smaller cortical surface area was observed in several regions in both cerebral hemispheres in ALL survivors. In these regions, mean surface area was 4.1-5.5% smaller in ALL survivors compared to healthy controls. In contrast, only one region showed lower cortical thickness in ALL survivors. There were no significant associations between cortical surface area/thickness in these regions and disease or treatment variables. In ALL survivors, smaller surface area in prefrontal regions, encompassing parts of the superior frontal gyri and the left anterior cingulate cortex, was associated with problems in executive functioning, specifically with emotional control and self-monitoring.

CONCLUSIONS

ALL survivors had smaller surface area in several cortical regions and smaller surface area in prefrontal regions was associated with reported problems in executive functioning.

Donepezil for Irradiated Brain Tumor Survivors: A Phase III Randomized Placebo-Controlled Clinical Trial

PURPOSE

Neurotoxic effects of brain irradiation include cognitive impairment in 50% to 90% of patients. Prior studies have suggested that donepezil, a neurotransmitter modulator, may improve cognitive function.

PATIENTS AND METHODS

A total of 198 adult brain tumor survivors ≥ 6 months after partial- or whole-brain irradiation were randomly assigned to receive a single daily dose (5 mg for 6 weeks, 10 mg for 18 weeks) of donepezil or placebo. A cognitive test battery assessing memory, attention, language, visuomotor, verbal fluency, and executive functions was administered before random assignment and at 12 and 24 weeks. A cognitive composite score (primary outcome) and individual cognitive domains were evaluated.

RESULTS

Of this mostly middle-age, married, non-Hispanic white sample, 66% had primary brain tumors, 27% had brain metastases, and 8% underwent prophylactic cranial irradiation. After 24 weeks of treatment, the composite scores did not differ significantly between groups (P = .48); however, significant differences favoring donepezil were observed for memory (recognition, P = .027; discrimination, P = .007) and motor speed and dexterity (P = .016). Significant interactions between pretreatment cognitive function and treatment were found for cognitive composite (P = .01), immediate recall (P = .05), delayed recall (P = .004), attention (P = .01), visuomotor skills (P = .02), and motor speed and dexterity (P < .001), with the benefits of donepezil greater for those who were more cognitively impaired before study treatment.

CONCLUSION

Treatment with donepezil did not significantly improve the overall composite score, but it did result in modest improvements in several cognitive functions, especially among patients with greater pretreatment impairments.

Survivorship: cognitive function, version 1.2014

Cognitive impairment is a common complaint among cancer survivors and may be a consequence of the tumors themselves or direct effects of cancer-related treatment (eg, chemotherapy, endocrine therapy, radiation). For some survivors, symptoms persist over the long term and, when more severe, can impact quality of life and function. This section of the NCCN Guidelines for Survivorship provides assessment, evaluation, and management recommendations for cognitive dysfunction in survivors. Nonpharmacologic interventions (eg, instruction in coping strategies; management of distress, pain, sleep disturbances, and fatigue; occupational therapy) are recommended, with pharmacologic interventions as a last line of therapy in survivors for whom other interventions have been insufficient.

Medical management of brain tumors and the sequelae of treatment

Patients with malignant brain tumors are prone to complications that negatively impact their quality of life and sometimes their overall survival as well. Tumors may directly provoke seizures, hypercoagulable states with resultant venous thromboembolism, and mood and cognitive disorders. Antitumor treatments and supportive therapies also produce side effects. In this review, we discuss major aspects of supportive care for patients with malignant brain tumors, with particular attention to management of seizures, venous thromboembolism, corticosteroids and their complications, chemotherapy including bevacizumab, and fatigue, mood, and cognitive dysfunction.

Reliable change in neuropsychological assessment of breast cancer survivors

BACKGROUND

The purpose of this study was to enhance the current understanding and interpretation of longitudinal change on tests of neurocognitive function in individuals with cancer. Scores on standard neuropsychological instruments may be impacted by practice effects and other random forms of error.

METHODS

The current study assessed the test-retest reliability of several tests and overarching cognitive domains comprising a neurocognitive battery typical of those used for research and clinical evaluation using relevant time frames. Practice effect-adjusted reliable change confidence intervals for test-retest difference scores based on a sample of patient-matched healthy controls are provided.

RESULTS

By applying reliable change confidence intervals to scores from two samples of breast cancer patients at post-treatment follow-up assessment, meaningful levels of detectable change in cognitive functioning in breast cancer survivors were ascertained and indicate that standardized neuropsychological instruments may be subject to limitations in detection of subtle cognitive dysfunction over clinically relevant intervals, especially in patient samples with average to above average range baseline functioning.

CONCLUSIONS

These results are discussed in relation to reported prevalence of cognitive change in breast cancer patients along with recommendations for study designs that enhance detection of treatment effects.

Systematic review of pharmacologic and non-pharmacologic interventions to manage cognitive alterations after chemotherapy for breast cancer

PURPOSE

Cognitive alterations are reported in breast cancer patients receiving chemotherapy. This has adverse effects on patients' quality of life and function. This systematic review investigates the effectiveness of pharmacologic and non-pharmacologic interventions to manage cognitive alterations associated with breast cancer treatment.

METHODS

Medline via EBSCO host, CINAHL and Cochrane CENTRAL were searched for the period January 1999-May 2014 for prospective randomised controlled trials related to the management of chemotherapy-associated cognitive alterations. Included studies investigated the management of chemotherapy-associated cognitive alterations and used subjective or objective measures in patients with breast cancer during or after chemotherapy. Two authors independently extracted data and assessed the risk of bias.

RESULTS

Thirteen studies involving 1138 participants were included. Overall, the risk of bias for the 13 studies was either high (n=11) or unclear (n=2). Pharmacologic interventions included psychostimulants (n=4), epoetin alfa (n=1) and Ginkgo biloba (n=1). Non-pharmacologic interventions were cognitive training (n=5) and physical activity (n=2). Pharmacologic agents were ineffective except for self-reported cognitive function in an epoetin alfa study. Cognitive training interventions demonstrated benefits in self-reported cognitive function, memory, verbal function and language and orientation/attention. Physical activity interventions were effective in improving executive function and self-reported concentration.

CONCLUSION

Current evidence does not favour the pharmacologic management of cognitive alterations associated with breast cancer treatment. Cognitive training and physical activity interventions appear promising, but additional studies are required to establish their efficacy. Further research is needed to overcome methodological shortfalls such as heterogeneity in participant characteristics and non-standardised neuropsychological outcome measures.

Chemobrain: a critical review and causal hypothesis of link between cytokines and epigenetic reprogramming associated with chemotherapy

One consequence of modern cancer therapy is chemotherapy related cognitive dysfunction or "chemobrain", the subjective experience of cognitive deficits at any point during or following chemotherapy. Chemobrain, a well-established clinical syndrome, has become an increasing concern because the number of long-term cancer survivors is growing dramatically. There is strong evidence that correlates changes in peripheral cytokines with the development of chemobrain in commonly used chemotherapeutic drugs for different types of cancer. However, the mechanisms by which these cytokines elicit change in the central nervous system are still unclear. In this review, we hypothesize that the administration of chemotherapy agents initiates a cascade of biological changes, with short-lived alterations in the cytokine milieu inducing persistent epigenetic alterations. These epigenetic changes lead to changes in gene expression, alterations in metabolic activity and neuronal transmission that are responsible for generating the subjective experience of cognition. This speculative but testable hypothesis should help to gain a comprehensive understanding of the mechanism underlying cognitive dysfunction in cancer patients. Such knowledge is critical to identify pharmaceutical targets with the potential to prevent and treat cancer-treatment related cognitive dysfunction and similar disorders.

Very Late Treatment-Related Alterations in Brain Function of Breast Cancer Survivors

Although adjuvant chemotherapy (CT) for breast cancer (BC) is associated with very late side-effects on cognition and brain function, studies on adverse effects of specific treatment regimens are scarce. Here, neurotoxicity profiles after different treatment strategies were compared in BC survivors randomized to high-dose (HI) or conventional-dose (CON-) CT, in women treated with radiotherapy (RT) -only and a healthy control (HC) group. We administered a neurocognitive test battery, a planning fMRI task (Tower of London) and episodic memory fMRI task (Paired Associates paradigm) in BC survivors who received CON-CT (n=24) and HC (n=27). Data were compared to BC survivors who received HI-CT (n=17) and RT-only (n=15) and who were previously assessed. Testing took place ±11.5 years post-CT. Furthermore, neurocognitive data were compared to neurocognitive data acquired ≤2 years post-treatment. Cognitive assessment revealed sustained cognitive decline in 10.5% of HI-CT, 8.3% of CON-CT, 6.7% of RT-only patients and 0% in the HC. Hypoactivation was found in task-related prefrontal and parietal areas for both CT-groups versus RT-only, with HI-CT showing more pronounced hypoactivation than CON-CT, combined with worse task performance. RT-only survivors performed at a similar level to HC while showing hyperactivation in task-related brain areas. Long after treatment, CT is associated with cognitive problems and task-related hypoactivation that depend on the specific cytotoxic regimen. This worse performance in patients who received CT could be explained by impaired brain functioning that is more severe with more intense CT.

Cognitive impact of cytotoxic agents in mice

RATIONALE AND OBJECTIVES

Adjuvant chemotherapy is associated with changes in cognition in a subgroup of cancer patients. Chemotherapy is generally given as a combination of cytotoxic agents, which makes it hard to define the agent responsible for these observed changes. Literature on animal experiments has been difficult to interpret due to variance in experimental setup.

METHODS

We examined the effects of cytotoxic agents administered separately on various cognitive measures in a standardized animal model. Male C57Bl/6 mice received cyclophosphamide, docetaxel, doxorubicin, 5-fluorouracil, methotrexate, or topotecan. These agents represent different compound classes based on their working mechanism and are frequently prescribed in the clinic. A control group received saline. Behavioral testing started 2 or 15 weeks after treatment and included testing general measures of behavior and cognitive task performance: spontaneous behavior in an automated home cage, open field, novel location recognition (NLR), novel object recognition (NOR), Barnes maze, contextual fear conditioning, and a simple choice reaction time task (SCRTT).

RESULTS

Cyclophosphamide, docetaxel, and doxorubicin administration affected spontaneous activity in the automated home cage. All cytotoxic agents affected memory (NLR and/or NOR). Spatial memory measured in the Barnes maze was affected after administration with doxorubicin, 5-fluorouracil, and topotecan. Decreased inhibition in the SCRTT was observed after treatment with cyclophosphamide, docetaxel, and topotecan.

CONCLUSIONS

Our data show that, in mice, a single treatment with a cytotoxic agent causes cognitive impairment. Not all cytotoxic agents affected the same cognitive domains, which might be explained by differences in working mechanisms of the various agents.

The association of cognitive fatigue with menopause, depressive symptoms, and quality of life in ambulatory breast cancer patients

BACKGROUND

The causes of cancer-related fatigue, which can influence patients' activities, are multidimensional; however, little is known about the cognitive dimension. We examined the association of cognitive fatigue with menopause, depressive symptoms, and quality of life in ambulatory breast cancer patients after primary treatment.

METHODS

This descriptive, cross-sectional study recruited 20-64-year-old breast cancer patients in an outpatient setting. The patients (N = 93; mean age = 53 years) were divided into low (L-CogF) and high-cognitive fatigue (H-CogF) groups according to their scores on the cognitive fatigue subscale of the Cancer Fatigue Scale. We compared the groups on their sociodemographic and medical characteristics and scores on the Functional Assessment of Cancer Therapy-Breast (FACT-B) [a measure of quality of life (QOL)], Simplified Menopausal Index (SMI), and Self-Rating Questionnaire for Depression (SRQ-D).

RESULTS

The L-CogF (n = 55) and H-CogF (n = 38) patients did not differ in age, years since diagnosis, marital status, educational background, or treatment history. Total and subscale FACT-B scores, except for physical well-being, were significantly lower in H-CogF participants than in L-CogF participants. SMI and SRQ-D scores were significantly higher in H-CogF participants. Employed H-CogF participants were concerned about keeping their jobs (p < 0.05).

CONCLUSIONS

Breast cancer patients with high-cognitive fatigue suffer from severe menopause and depressive symptoms, and deteriorating QOL. Cognitive fatigue should be considered when interpreting patients' cognitive complaints.

Shared Medical Appointments in Cancer Survivorship Care: A Review of the Literature

PURPOSE

The physical and psychological effects of a cancer diagnosis and treatment on an individual may be significant and require appropriate monitoring and management. Furthermore, attention to preventive care and comorbid medical conditions is critical. Innovative approaches are needed to provide quality care to this growing population.

METHODS

We reviewed the literature evaluating shared medical appointments (SMAs) in noncancer and cancer care settings. Supported by a conceptual framework and adhering to the goals of patient-centered communication, we propose how SMAs may be used in clinical practice to enhance survivorship care.

RESULTS

The literature suggests that SMAs are an effective model in noncancer settings, showing improved blood pressure and health-related quality of life, among others. Although evidence for SMAs in cancer care is limited, there is significant potential for improved patient outcomes and costs. In particular, SMAs may provide an opportunity to address medical and psychological needs while creating a structure for enhanced communication.

CONCLUSION

SMAs may offer an innovative care model for cancer survivors and their providers. Implementation and evaluation of SMAs in the care of cancer survivors is warranted.

Association of cancer history with Alzheimer's disease onset and structural brain changes

Epidemiological studies show a reciprocal inverse association between cancer and Alzheimer's disease (AD). The common mechanistic theory for this effect posits that cells have an innate tendency toward apoptotic or survival pathways, translating to increased risk for either neurodegeneration or cancer. However, it has been shown that cancer patients experience cognitive dysfunction pre- and post-treatment as well as alterations in cerebral gray matter density (GMD) on MRI. To further investigate these issues, we analyzed the association between cancer history (CA±) and age of AD onset, and the relationship between GMD and CA± status across diagnostic groups in the Alzheimer's Disease Neuroimaging Initiative (ADNI) cohort study. Data was analyzed from 1609 participants with information on baseline cancer history and AD diagnosis, age of AD onset, and baseline MRI scans. Participants were CA+ (N = 503) and CA− (N = 1106) diagnosed with AD, mild cognitive impairment (MCI), significant memory concerns (SMC), and cognitively normal older adults. As in previous studies, CA+ was inversely associated with AD at baseline (P = 0.025); interestingly, this effect appears to be driven by non-melanoma skin cancer (NMSC), the largest cancer category in this study (P = 0.001). CA+ was also associated with later age of AD onset (P < 0.001), independent of apolipoprotein E (APOE) ε4 allele status, and individuals with two prior cancers had later mean age of AD onset than those with one or no prior cancer (P < 0.001), suggesting an additive effect. Voxel-based morphometric analysis of GMD showed CA+ had lower GMD in the right superior frontal gyrus compared to CA− across diagnostic groups (P_crit < 0.001, uncorrected); this cluster of lower GMD appeared to be driven by history of invasive cancer types, rather than skin cancer. Thus, while cancer history is associated with a measurable delay in AD onset independent of APOE ε4, the underlying mechanism does not appear to be cancer-related preservation of GMD.

Perceived cognitive impairment in Chinese patients with breast cancer and its relationship with post-traumatic stress disorder symptoms and fatigue

OBJECTIVE

Clinical reports have shown that adjuvant chemotherapy has a negative impact on perceived cognitive impairment (PCI) of patients with breast cancer; however, evidence concerning the effects of psychological factors such as post-traumatic stress disorder (PTSD) symptoms on PCI is limited, especially in relation to Chinese patients with breast cancer. This research investigated the associations between psychological factors and PCI in Chinese women with breast cancer.

METHODS

In total, 204 women with breast cancer were assessed for PCI, PTSD symptoms, fatigue, anxiety, and depression using self-report measures. Hierarchical linear regression was conducted to investigate the associations between the variables of interest and PCI.

RESULTS

Two hundred and two women were included in the final analysis; two of those originally tested were excluded because of missing data. A univariate analysis showed that PCI was significantly related to education, PTSD symptoms (re-experience, avoidance, and hyperarousal), fatigue, depression, anxiety, and undergoing chemotherapy or radiotherapy. Hierarchical linear regression revealed that PTSD symptoms and fatigue (ΔR(2)  = 0.26, P < 0.001) independently accounted for PCI in Chinese women with breast cancer regardless of age, education level, chemotherapy and radiotherapy. Hyperarousal was the only contributing PTSD symptom to PCI (B = -1.24, SE = 0.33, β = -0.39, P < 0.001).

CONCLUSIONS

Besides chemotherapy, PTSD symptoms, especially hyperarousal, and fatigue are important risk factors for significant PCI and are therefore worthy of further investigation.

Yoga and self-reported cognitive problems in breast cancer survivors: a randomized controlled trial

OBJECTIVES

Cancer survivors often report cognitive problems. Furthermore, decreases in physical activity typically occur over the course of cancer treatment. Although physical activity benefits cognitive function in noncancer populations, evidence linking physical activity to cognitive function in cancer survivors is limited. In our recent randomized controlled trial, breast cancer survivors who received a yoga intervention had lower fatigue and inflammation following the trial compared with a wait list control group. This secondary analysis of the parent trial addressed yoga's impact on cognitive complaints.

METHODS

Posttreatment stage 0-IIIA breast cancer survivors (n = 200) were randomized to a 12-week, twice-weekly Hatha yoga intervention or a wait list control group. Participants reported cognitive complaints using the Breast Cancer Prevention Trial Cognitive Problems Scale at baseline, immediately postintervention, and 3-month follow-up.

RESULTS

Cognitive complaints did not differ significantly between groups immediately postintervention (p = 0.250). However, at 3-month follow-up, yoga participants' Breast Cancer Prevention Trial Cognitive Problems Scale scores were an average of 23% lower than wait list participants' scores (p = 0.003). These group differences in cognitive complaints remained after controlling for psychological distress, fatigue, and sleep quality. Consistent with the primary results, those who practiced yoga more frequently reported significantly fewer cognitive problems at 3-month follow-up than those who practiced less frequently (p < 0.001).

CONCLUSIONS

These findings suggest that yoga can effectively reduce breast cancer survivors' cognitive complaints and prompt further research on mind-body and physical activity interventions for improving cancer-related cognitive problems.

Cancer, coping, and cognition: a model for the role of stress reactivity in cancer-related cognitive decline

BACKGROUND

Cognitive decline and accompanying neurological changes associated with non-CNS cancer diagnosis and treatment have been increasingly identified in a subset of patients. Initially believed to be because of neurotoxic effects of chemotherapy exposure, observation of cognitive decline in patients not treated with chemotherapy, cancer-diagnosed individuals prior to treatment, and patients receiving alternative treatment modalities (surgery, endocrine therapy, and radiation) has led to the investigation of additional potential etiologies and moderating factors. Stressful experiences have long been posited as a contributor to these cognitive changes. Through reciprocal connectivity with peripheral systems, the brain maintains a dynamic circuitry to adapt to stress (allostasis). However, overuse of this system leads to dysregulation and contributes to pathophysiology (allostatic load). At this time, little research has been conducted to systematically examine the role of allostatic load in cancer-related cognitive dysfunction.

METHODS AND RESULTS

Here, we integrate theories of stress biology, neuropsychology, and coping and propose a model through which individuals with a high level of allostatic load at diagnosis may be particularly vulnerable to the neurocognitive effects of cancer.

CONCLUSIONS

Opportunities for future research to test and extend proposed mechanisms are discussed in addition to points of prevention and intervention based on individual variation in stress reactivity and coping skills.

Cognitive function after the initiation of adjuvant endocrine therapy in early-stage breast cancer: an observational cohort study

PURPOSE

This report examines cognitive complaints and neuropsychological (NP) testing outcomes in patients with early-stage breast cancer after the initiation of endocrine therapy (ET) to determine whether this therapy plays any role in post-treatment cognitive complaints.

PATIENTS AND METHODS

One hundred seventy-three participants from the Mind Body Study (MBS) observational cohort provided data from self-report questionnaires and NP testing obtained at enrollment (T1, before initiation of ET), and 6 months later (T2). Bivariate analyses compared demographic and treatment variables, cognitive complaints, depressive symptoms, quality of life, and NP functioning between those who received ET versus not. Multivariable linear regression models examined predictors of cognitive complaints at T2, including selected demographic variables, depressive symptoms, ET use, and other medical variables, along with NP domains that were identified in bivariate analyses.

RESULTS

Seventy percent of the 173 MBS participants initiated ET, evenly distributed between tamoxifen or aromatase inhibitors. ET-treated participants reported significantly increased language and communication (LC) cognitive complaints at T2 (P = .003), but no significant differences in NP test performance. Multivariable regression on LC at T2 found higher LC complaints significantly associated with T1 LC score (P < .001), ET at T2 (P = .004), interaction between ET and past hormone therapy (HT) (P < .001), and diminished improvement in NP psychomotor function (P = .05). Depressive symptoms were not significant (P = .10).

CONCLUSION

Higher LC complaints are significantly associated with ET 6 months after starting treatment and reflect diminished improvements in some NP tests. Past HT is a significant predictor of higher LC complaints after initiation of ET.

Preliminary Development and Evaluation of an Algorithm to Identify Breast Cancer Chemotherapy Toxicities Using Electronic Medical Records and Administrative Data

PURPOSE

Breast cancer chemotherapy toxicity is not well documented outside of randomized trials. We developed and conducted preliminary evaluation of an algorithm to detect grade 3 and 4 toxicities using electronic data from a large integrated managed care organization.

METHODS

The algorithm used administrative, pharmacy, and electronic data from outpatient, emergency room, and inpatient records of 99 women diagnosed with breast cancer from 2006 to 2009 who underwent chemotherapy. Data were abstracted for 12 months post-treatment initiation (24 months for trastuzumab recipients). An oncology nurse independently blindly reviewed records; these results were the "gold standard." Sensitivity and specificity were calculated for overall toxicity, categories of toxicities, and toxicity by age or regimen. The algorithm was applied to an independent sample of 1,575 patients with breast cancer diagnosed during the study period to estimate prevalence rates.

RESULTS

The overall sensitivity for detecting chemotherapy-related toxicity was 89% (95% CI, 77% to 95%). The highest sensitivity was for identification of hematologic toxicities (97%; 95% CI, 84% to 99%). There were good sensitivities for infectious toxicity, but rates dropped for GI and neurological toxicities. Specificity was high within each category (89% to 99%), but when combined to measure any toxicity, it was lower (70%; 95% CI, 57% to 81%). When applied to an independent chemotherapy sample, the algorithm estimates a 26% rate of hematologic toxicity; rates were higher among patients age ≥ 65 years versus less than 65 years.

CONCLUSIONS

If validated in other samples and health care settings, algorithms to capture toxicity could be useful in comparative and cost-effectiveness evaluations of community practice-delivered treatment.

Cognitive effects of cancer systemic therapy: implications for the care of older patients and survivors

The number of patients with cancer who are age 65 years or older (hereinafter "older") is increasing dramatically. One obvious aspect of cancer care for this group is that they are experiencing age-related changes in multiple organ systems, including the brain, which complicates decisions about systemic therapy and assessments of survivorship outcomes. There is a consistent body of evidence from studies that use neuropsychological testing and neuroimaging that supports the existence of impairment following systemic therapy in selected cognitive domains among some older patients with cancer. Impairment in one or more cognitive domains could have important effects in the daily lives of older patients. However, an imperfect understanding of the precise biologic mechanisms underlying cognitive impairment after systemic treatment precludes development of validated methods for predicting which older patients are at risk. From what is known, risks may include lifestyle factors such as smoking, genetic predisposition, and specific comorbidities such as diabetes and cardiovascular disease. Risk also interacts with physiologic and cognitive reserve, because even at the same chronological age and with the same number of illnesses, older patients vary from having high reserve (ie, biologically younger than their age) to being frail (biologically older than their age). Surveillance for the presence of cognitive impairment is also an important component of long-term survivorship care with older patients. Increasing the workforce of cancer care providers who have geriatrics training or who are working within multidisciplinary teams that have this type of expertise would be one avenue toward integrating assessment of the cognitive effects of cancer systemic therapy into routine clinical practice.

A prospective evaluation of changes in brain structure and cognitive functions in adult stem cell transplant recipients

Hematopoietic stem cell transplantation (HSCT) is an efficacious treatment for many hematologic malignancies. However, the conditioning regimen of high-dose (HD) chemotherapy with or without total body irradiation (TBI) can be associated with neurotoxicity. In this prospective study, we used quantitative neuroimaging techniques to examine regional gray matter and ventricular volumes, and standardized neuropsychological tests to assess cognitive function before and 1 year after HSCT in 28 patients with hematologic malignancies and in ten healthy controls evaluated at similar intervals. Nineteen patients received conditioning treatment with HD chemotherapy alone and nine had both TBI and HD chemotherapy. There was a significant reduction in gray matter volume in the middle frontal gyrus bilaterally and in the left caudate nucleus in the patient group (all patients combined) but not among healthy controls over the 1-year follow-up period. There was a significant increase in left lateral ventricle volume and in total ventricle volume in the patient group, relative to healthy controls. Similar brain structural changes were seen for patients treated with HD chemotherapy alone. The neuropsychological results showed that 21% of patients could be classified as impaired at baseline. The Reliable Change Index suggested no significantly different rates of cognitive decline between patients and healthy controls. The findings suggest that HSCT patients may be at an increased risk for developing regional brain volume loss, and that subgroups may experience cognitive dysfunction prior to and 1 year following the transplant.

Alterations in brain structure related to breast cancer and its treatment: chemotherapy and other considerations

Cognitive effects of cancer and its treatment have been a topic of increasing investigation over the past ~30 years. Recent studies have focused on better understanding the neural correlates of these effects, with an emphasis on post-chemotherapy effects in breast cancer patients. Structural MRI studies have utilized both automated and manual approaches to quantify gray and white matter characteristics (e.g., regional volume and density) in breast cancer patients treated with chemotherapy relative to patients who did not receive chemotherapy and/or healthy controls. While most work to date has been retrospective, a small number of baseline (pre-systemic therapy) and prospective longitudinal studies have been conducted. Data have consistently shown lower gray and white matter volume and density in patients treated with chemotherapy, particularly in frontal and temporal brain regions. Host factors and/or the cancer disease process and other therapies (e.g., antiestrogen treatment) also seem likely to contribute to the observed differences, though the relative contributions of these effects have not yet been investigated in detail. These structural abnormalities have been shown to relate to subjective and objective cognitive functioning, as well as to biological factors that may help to elucidate the underlying mechanism(s). This review examines the currently available published observations and discusses the major themes and promising directions for future studies.

Learning and memory performance in a cohort of clinically referred breast cancer survivors: the role of attention versus forgetting in patient-reported memory complaints

OBJECTIVE

While forgetfulness is widely reported by breast cancer survivors, studies documenting objective memory performance yield mixed, largely inconsistent, results. Failure to find consistent, objective memory issues may be due to the possibility that cancer survivors misattribute their experience of forgetfulness to primary memory issues rather than to difficulties in attention at the time of learning.

METHODS

To clarify potential attention issues, factor scores for Attention Span, Learning Efficiency, Delayed Memory, and Inaccurate Memory were analyzed for the California Verbal Learning Test-Second Edition (CVLT-II) in 64 clinically referred breast cancer survivors with self-reported cognitive complaints; item analysis was conducted to clarify specific contributors to observed effects, and contrasts between learning and recall trials were compared with normative data. Performance on broader cognitive domains is also reported.

RESULTS

The Attention Span factor, but not Learning Efficiency, Delayed Memory, or Inaccurate Memory factors, was significantly affected in this clinical sample. Contrasts between trials were consistent with normative data and did not indicate greater loss of information over time than in the normative sample.

CONCLUSIONS

Results of this analysis suggest that attentional dysfunction may contribute to subjective and objective memory complaints in breast cancer survivors. These results are discussed in the context of broader cognitive effects following treatment for clinicians who may see cancer survivors for assessment.

Cognitive impairment in older patients with breast cancer before systemic therapy: is there an interaction between cancer and comorbidity?

PURPOSE

To determine if older patients with breast cancer have cognitive impairment before systemic therapy.

PATIENTS AND METHODS

Participants were patients with newly diagnosed nonmetastatic breast cancer and matched friend or community controls age > 60 years without prior systemic treatment, dementia, or neurologic disease. Participants completed surveys and a 55-minute battery of 17 neuropsychological tests. Biospecimens were obtained for APOE genotyping, and clinical data were abstracted. Neuropsychological test scores were standardized using control means and standard deviations (SDs) and grouped into five domain z scores. Cognitive impairment was defined as any domain z score two SDs below or ≥ two z scores 1.5 SDs below the control mean. Multivariable analyses evaluated pretreatment differences considering age, race, education, and site; comparisons between patient cases also controlled for surgery.

RESULTS

The 164 patient cases and 182 controls had similar neuropsychological domain scores. However, among patient cases, those with stage II to III cancers had lower executive function compared with those with stage 0 to I disease, after adjustment (P = .05). The odds of impairment were significantly higher among older, nonwhite, less educated women and those with greater comorbidity, after adjustment. Patient case or control status, anxiety, depression, fatigue, and surgery were not associated with impairment. However, there was an interaction between comorbidity and patient case or control status; comorbidity was strongly associated with impairment among patient cases (adjusted odds ratio, 8.77; 95% CI, 2.06 to 37.4; P = .003) but not among controls (P = .97). Only diabetes and cardiovascular disease were associated with impairment among patient cases.

CONCLUSION

There were no overall differences between patients with breast cancer and controls before systemic treatment, but there may be pretreatment cognitive impairment within subgroups of patient cases with greater tumor or comorbidity burden.

Proposed mechanisms for cancer- and treatment-related cognitive changes

OBJECTIVES

To review the proposed mechanisms of cognitive changes associated with non-central nervous system cancers and cancer treatment.

DATA SOURCES

Review and synthesis of databased publications and review articles.

CONCLUSION

Proposed mechanisms include cytokine upregulation, hormonal changes, neurotransmitter dysregulation, attentional fatigue, genetic predisposition, and comorbid symptoms.

IMPLICATIONS FOR NURSING PRACTICE

Oncology nurses need to understand the multiple mechanisms that may contribute to the development of cancer- and treatment-related cognitive changes so that they can identify patients at high risk and help patients understand why these changes occur.

Memory and cancer: a review of the literature

The mental health of cancer survivors has not always been the primary emphasis of treatment protocols since physical health outcomes have taken precedence. Older cancer survivors experience a double jeopardy since they are at risk for memory impairments and mild cognitive impairment and because they are greater than 55 years of age. Of the 9.6 million cancer survivors in the US who have completed active treatment, many report cognitive difficulties, with labels such as "chemo brain," "not as sharp," "woolly-headedness," or the "mind does not work as quickly". To date, most of our knowledge of cognitive impairment in cancer survivors comes from female breast cancer survivors. Studies indicate that these survivors have diminished executive function, verbal memory, and motor function. Cancer survivors want to live independently in the community for as long as possible however, these cognitive deficits may prevent this desired lifestyle. To broaden our understanding this paper reviews the literature on the cognitive impairment and memory deficits experienced by three groups of cancer survivors breast, colorectal, and prostate cancer, that make up 60% of all survivors nationally. Even though mental health declined after a cancer diagnosis, the long-term outcomes of cancer survivors did not differ from persons without cancer in depression or cognitive function.

Monitoring and optimising cognitive function in cancer patients: Present knowledge and future directions

The potentially detrimental effects of cancer and related treatments on cognitive functioning are emerging as a key focus of cancer survivorship research. Many patients with central nervous system (CNS) or non-CNS tumours develop cognitive problems during the course of their disease that can result in diminished functional independence. We review the state of knowledge on the cognitive functioning of patients with primary and secondary brain tumours at diagnosis, during and after therapy, and discuss current initiatives to diminish cognitive decline in these patients. Similarly, attention is paid to the cognitive sequelae of cancer and cancer therapies in patients without CNS disease. Disease and treatment effects on cognition are discussed, as well as current insights into the neural substrates and the mechanisms underlying cognitive dysfunction in these patients. In addition, rehabilitation strategies for patients with non-CNS disease confronted with cognitive dysfunction are described. Special attention is given to knowledge gaps in the area of cancer and cognition, in CNS and non-CNS diseases. Finally, we point to the important role for cooperative groups to include cognitive endpoints in clinical trials in order to accelerate our understanding and treatment of cognitive dysfunction related to cancer and cancer therapies.

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.

Population-level trends in posttreatment cancer survivors' concerns and associated receipt of care: results from the 2006 and 2010 LIVESTRONG surveys

There is a need to better understand the posttreatment concerns of the nearly 14 million survivors of cancer alive in the United States today and their receipt of care. Using data from 2,910 posttreatment survivors of cancer from the 2006 or 2010 LIVESTRONG Surveys, the authors examined physical, emotional, and practical concerns, receipt of care, and trends in these outcomes at the population level.

RESULTS

89% of respondents reported at least one physical concern (67% received associated posttreatment care), 90% reported at least one emotional concern (47% received care), and 45% reported at least one practical concern (36% received care). Female survivors, younger survivors, those who received more intensive treatment, and survivors without health insurance often reported a higher burden of posttreatment concerns though were less likely to have received posttreatment care. These results reinforce the importance of posttreatment survivorship and underscore the need for continued progress in meeting the needs of this population. Efforts to increase the availability of survivorship care are extremely important to improve the chances of people affected by cancer living as well as possible in the posttreatment period.

Improving quality of life in female cancer survivors: current status and future questions

ABSTRACT: 

Almost 14 million people in the USA alone have been diagnosed with cancer. Given the improvements in diagnosis and treatment, over 60% of patients are expected to survive 5 years or more from the point of diagnosis. Treatments for cancer may result in long-term issues including those that impact the physical, emotional, spiritual or social domains. However, how best to care for issues in survivors remains unclear. Although much attention has been focused on survivorship care plans and survivorship clinics, there are limited data to show they improve outcomes. This article reviews the issues in female cancer survivors that can occur following diagnosis and treatment and suggest strategies that may assist in management. Finally, we review the current views regarding the care of cancer survivors and suggest important issues that must be addressed so that we can reach our goal of improvement in the quality of life of this emerging population.

Longitudinal assessment of cognitive changes associated with adjuvant treatment for breast cancer: the impact of APOE and smoking

PURPOSE

This study examined the association of post-treatment changes in cognitive performance, apolipoprotein E (APOE), and smoking in breast cancer patients treated with adjuvant therapy.

PARTICIPANTS AND METHODS

Breast cancer patients treated with chemotherapy (N = 55, age = 51.9 ± 7.1, education = 15.7 ± 2.6) were evaluated with a battery of neuropsychological tests prior to chemotherapy and at 1, 6, and 18 months post-chemotherapy. Matched groups of breast cancer patients not exposed to chemotherapy (N = 68, age = 56.8 ± 8.3, education = 14.8 ± 2.2) and healthy controls (N = 43, age = 53.0 ± 10.1, education = 15.2 ± 2.6) were evaluated at similar intervals. APOE epsilon 4 carrier status (APOE4+) and smoking history were also evaluated.

RESULTS

The detrimental effect of APOE4+ genotype on post-treatment cognitive functioning was moderated by smoking history, that is, patients without a smoking history had significantly lower performance on measures of processing speed and working memory compared with those with a smoking history and healthy controls. Exploratory analyses revealed that APOE4+ patients without a smoking history who were exposed to chemotherapy showed a decline in performance in processing speed, compared with patients with a smoking history. A similar but less pronounced pattern was seen in the no chemotherapy group (primarily endocrine treatment). For working memory, the APOE4+ by smoking interaction was observed in the no chemotherapy group only.

CONCLUSIONS

The association between APOE status, breast cancer treatment, and cognitive functioning was moderated by smoking history suggesting that both chemotherapy and endocrine therapy interact with APOE status and smoking to influence cognition. A putative mechanism is that smoking corrects a deficit in nicotinic receptor functioning and dopamine levels in APOE4+ individuals.

Self-reported cognitive concerns and abilities: two sides of one coin?

OBJECTIVE

Patient-reported cognitive function can be measured using negatively worded items (concerns) and positively worded (abilities) items. It is possible that reporting abilities is less subject to the influence of emotional states. This study evaluated the relationship between cognitive concerns and cognitive abilities.

METHODS

Cancer patients (N = 509; mean age = 61 years; 50% men; 86% White) completed concerns and abilities items developed by the National Institutes of Health Patient-Reported Outcomes Information System (PROMIS). Confirmatory factor analysis was used to evaluate the extent to which items were loaded on one single factor (unidimensionality). Multidimensionality was evaluated using bi-factor analysis (local factors: concerns and abilities). Slope parameters from multidimensional item response theory (IRT) and unidimensional IRT were compared to evaluate which factor solution fits best.

RESULTS

Acceptable fit indices were found in both one-factor confirmatory factor analysis (comparative fit index (CFI) = 0.96; root mean squared error of approximation (RMSEA) = 0.062) and bi-factor analysis (CFI = 0.98; RMSEA = 0.043). Thus, abilities and concerns could be considered as a single dimension. Yet, high loadings on the local factor in bi-factor analysis and slope discrepancies between unidimensional IRT and multidimensional IRT indicate that abilities should be considered as a separate factor from concerns.

CONCLUSIONS

Concerns and abilities could be measured using one-unidimensional item bank. Results also support measuring each construct separately. We recommend a conservative approach by measuring and reporting concerns and abilities separately. We therefore recommend two separate but co-calibrated item banks in the PROMIS network: cognitive function item bank-concerns and cognitive function item bank-abilities. Both item banks showed good psychometric properties and are available for research and clinical purposes.

Intra-individual variability in women with breast cancer

Studies assessing cognitive functioning in women treated for breast cancer have used primarily standardized neuropsychological tests and examined accuracy and/or reaction time as outcome measures: they have been inconsistent in identifying the cognitive domains affected and the severity of deficits. In other contexts of neural development and disorders, measures of Intra-individual variability (IIV) have proven useful in identifying subtleties in performance deficits that are not captured by measures of central tendency. This article presents proof of concept that assessing IIV may also increase understanding of the cognitive effects of cancer treatment. We analyzed mean accuracy and reaction time, as well as IIV from 65 women with breast cancer and 28 age and education matched controls who performed the Conner's Continuous Performance Test, a "Go-NoGo" task. Although there were no significant differences between groups using measures of central tendency, there was a group × inter-stimulus interval (ISI) interaction for IIV Dispersion (p < .001). Patient Dispersion was more variable at shorter ISI than controls and less variable at long ISI, suggesting greater sensitivity to presentation speed. Interpretation of IIV differences requires further investigation. Our results suggest that future studies would benefit from designs that allow analysis of IIV measures in studies assessing cognition in cancer survivors.

Systemically treated breast cancer patients and controls: an evaluation of the presence of noncredible performance

This study sought to define the frequency of noncredible performance in breast cancer patients before, during and after completion of systemic treatment, as well as predictors of noncredible performance. We examined six datasets investigating the cognitive effects of chemotherapy and/or endocrine therapy. Embedded performance validity test (PVT) measures were identified and used to evaluate the datasets. One dataset included a standalone PVT. Possible noncredible performance was operationally defined as performance below criterion on three or more PVT indices. This was undertaken as cancer patients have been observed clinically to fail PVTs both in the context of external gain and independent of such motivators. A total of 534 breast cancer patients and 214 healthy controls were included in the analysis. Percentages of patients performing below cutoff on one or more PVT varied from 0% to 21.2%. Only 1 patient met the criterion of noncredible performance. Calculation of post-test probabilities indicated a more than 90% chance to detect noncredible performance. There is no evidence to suggest noncredible performance in breast cancer patients and healthy controls who choose to participate in research studies examining cognitive function. Thus, the observational data showing that non-central nervous system (CNS) cancer and therapies not targeting the CNS can have untoward effects on cognitive function are unlikely to be due to noncredible performance.

Feasibility and efficacy of speed-feedback therapy with a bicycle ergometer on cognitive function in elderly cancer patients in Japan

OBJECTIVE

We conducted this study with the aim of demonstrating the feasibility and efficacy of speed-feedback therapy with a bicycle ergometer on cognitive function in elderly cancer patients.

METHODS

The subjects were patients with breast or prostate cancer who were 65 years of age or over. Among 146 patients, 78 were randomly assigned to the intervention group (n = 38) or the control group (n = 40). The intervention group received speed-feedback therapy with a bicycle ergometer once a week for four successive weeks. The control group was advised to spend the 4-week period engaged in their routine activities. Evaluations were carried out at the baseline and 4 weeks after the baseline (week 4) using the Frontal Assessment Battery, the Barthel Index, the Lawton and Brody Instrumental Activities of Daily Living, and the Functional Assessment of Cancer Therapy-General ver.4. Data were analyzed by a two-way repeated-measures analysis of variance.

RESULTS

The mean score of Frontal Assessment Battery for the intervention group was higher than that for the control group at week 4. In addition to significant main effects of time and group, we also found a significant interaction between the two groups (p = 0.006). Moreover, all of the subjects in the intervention group could complete all the four sessions of therapy without any pain or distress.

CONCLUSION

These results suggest that speed-feedback therapy with a bicycle ergometer may be feasible as well as effective for improving the cognitive function in elderly cancer patients.