Assessment of the feasibility of a rehabilitation intervention program for breast cancer survivors with cognitive complaints

A neurotherapy protocol to remediate cognitive deficits after adjuvant chemotherapy: a pilot study

OBJECTIVES

Adjuvant chemotherapy for breast cancer is undeniably effective in increasing survival rates but many breast cancer survivors (BCS) exhibit side effects including nausea, fatigue, stress, and neurocognitive deficits, known as "chemobrain." This pilot study explored how neurotherapy, or EEG biofeedback, a non-pharmacological approach, improved neurocognitive, behavioral, and neurophysiological deficits associated with BCS who underwent chemotherapy.

METHODS

Subjects underwent 18 sessions of EEG biofeedback training, in which audio and visual feedback occurred with successful shifting of EEG patterns.

RESULTS

Quantitative EEG and assessment tests demonstrated neurophysiological, cognitive, and behavioral deficits in all nine subjects prior to training. EEG biofeedback resulted in significant improvements in neurophysiological, neurocognitive, and psychological functions in all nine subjects after training.

CONCLUSIONS

We propose that this intervention and related forms of EEG biofeedback have the potential to significantly alleviate common side effects of chemotherapy in BCS and therefore merits additional research attention.

CanCOG®: Cultural Adaptation of the Evidence-Based UCLA Cognitive Rehabilitation Intervention Program for Cancer Survivors in Portugal

Cognitive difficulties are highly prevalent and negatively impact cancer survivors' quality of life. The UCLA Cognitive Rehabilitation Intervention Program (in short, UCLA program) is an evidence-based intervention developed and tested in the US to address the cognitive complaints of cancer survivors. Since there are no cognitive rehabilitation programs available for Portuguese cancer-related settings, this study aimed to culturally adapt the UCLA program to Portugal. Nine steps were implemented for this cultural adaptation: needs assessment, initial contacts, translation, cultural adaptation, independent review by a panel of experts (n = 6), focus group discussions with cancer survivors (n = 11), systematization of inputs and improvement of the final materials, fidelity check, and preliminary acceptability assessment. The findings suggested that changes to the original materials were needed. A Portuguese name, "CanCOG^®-Reabilitação Cognitiva no Cancro" (in English "CanCOG^®-Cognitive Rehabilitation in Cancer"), and a logo were created to make it more memorable and appealing for the Portuguese population. The language was adjusted to ensure content accessibility and semantic and conceptual equivalence. Finally, references to several cultural aspects, such as habits, customs, and traditions, were adapted to fit the new cultural context. The UCLA program may be a promising tool to help alleviate the cognitive difficulties reported by cancer survivors in different cultural contexts. Future research is needed to confirm the feasibility, acceptability, and preliminary efficacy of its Portuguese version, "CanCOG^®-Reabilitação Cognitiva no Cancro".

A Delphi technique toward the development of a cognitive intervention framework module for breast cancer survivors with cognitive impairment following chemotherapy

Objective

Chemotherapy-related cognitive impairment (CRCI) is a well-known phenomenon among breast cancer survivors. Cognitive impairment among breast cancer survivors can significantly affect their quality of life and ability to function independently. However, there is a lack of specific and focused cognitive intervention to improve their cognitive performances. This study aimed to develop a tailored cognitive intervention framework module by adapting the attention and memory interventions from the Cognitive Rehabilitation Manual of the Brain Injury Interdisciplinary Special Interest Group (BI-SIG) of the American Congress of Rehabilitation Medicine (ACRM) and incorporating them with the relevant exercises for cognitive rehabilitation for Malaysian breast cancer survivors with CRCI based on the consensus agreement of the expert panel.

Methods and analysis

The Delphi consensus technique was conducted online to review and evaluate the framework module. A panel of experts, including rehabilitation medicine physicians, occupational therapists, and clinical psychologists in Malaysia, was invited to participate in this study. For each round, the expert consensus was defined as more than 90% of the expert panel agreeing or strongly agreeing with the proposed items.

Results

A total of 33 practitioners completed the three Delphi rounds. 72.7% of the expert panel have been practising in their relevant clinical fields for more than six years (M = 10.67, SD = 5.68). In Round 1, 23% of the experts suggested that the framework module for attention training required further improvements, specifically in the language (M = 1.97, SD = 0.75) and instructions (M = 2.03, SD = 0.71) provided. In Round 2, 15% of the experts recommended additional changes in the instruction (M = 2.15, SD = 0.67) for attention training. Amendments made to the framework module in line with the recommendations provided by the experts resulted in a higher level of consensus, as 94% to 100% of the experts in Round 3 concluded the framework module was suitable and comprehensive for our breast cancer survivors. Following the key results, the objectives were practical, and the proposed approaches, strategies, and techniques for attention and memory training were feasible. The clarity of the instructions, procedures, verbatim transcripts, and timeframe further enhanced the efficacy and utility of the framework module.

Conclusions

This study found out that the cognitive intervention framework module for breast cancer survivors with cognitive impairment following chemotherapy can be successfully developed and feasible to be implemented using Delphi technique.

Chemobrain in Breast Cancer: Mechanisms, Clinical Manifestations, and Potential Interventions

Among the potential adverse effects of breast cancer treatment, chemotherapy-related cognitive impairment (CRCI) has gained increased attention in the past years. In this review, we provide an overview of the literature regarding CRCI in breast cancer, focusing on three main aspects. The first aspect relates to the molecular mechanisms linking individual drugs commonly used to treat breast cancer and CRCI, which include oxidative stress and inflammation, reduced neurogenesis, reduced levels of specific neurotransmitters, alterations in neuronal dendrites and spines, and impairment in myelin production. The second aspect is related to the clinical characteristics of CRCI in patients with breast cancer treated with different drug combinations. Data suggest the incidence rates of CRCI in breast cancer vary considerably, and may affect more than 50% of treated patients. Both chemotherapy regimens with or without anthracyclines have been associated with CRCI manifestations. While cross-sectional studies suggest the presence of symptoms up to 20 years after treatment, longitudinal studies confirm cognitive impairments lasting for at most 4 years after the end of chemotherapy. The third and final aspect is related to possible therapeutic interventions. Although there is still no standard of care to treat CRCI, several pharmacological and non-pharmacological approaches have shown interesting results. In summary, even if cognitive impairments derived from chemotherapy resolve with time, awareness of CRCI is crucial to provide patients with a better understanding of the syndrome and to offer them the best care directed at improving quality of life.

Alfa band power increases in posterior brain regions in attention deficit hyperactivity disorder after digital cognitive stimulation treatment

The changes triggered by pharmacological treatments in resting-state alpha-band (8–14 Hz) oscillations have been widely studied in attention deficit hyperactivity disorder. However, to date, there has been no evidence regarding the possible changes in cognitive stimulation treatments on these oscillations. This paper sets out to verify whether cognitive stimulation treatments based on progressive increases in cognitive load can be effective in triggering changes in alpha-band power in attention deficit hyperactivity disorder. With this objective, we compared a cognitive stimulation treatment (n = 13) to placebo treatment (n = 13) for 12 weeks (36 sessions of 15 min) in child patients (8–11 years old) with attention deficit hyperactivity disorder. Two magnetoencephalographic recordings were acquired for all the participants. In order to extract the areas with changes in alpha power between both magnetoencephalographic recordings, the differences in the power ratio (pre/post-condition) were calculated using an Analysis of Covariance test adjusted for the age variable. The results show an increase in the post-treatment power ratio in the experimental group versus the placebo group (P < 0.01) in posterior regions and the default mode network. In addition, these alpha changes were related to measures of attention, working memory and cognitive flexibility. The results seem to indicate that cognitive stimulation treatment based on progressive increases in cognitive load triggers alpha-band power changes in child attention deficit hyperactivity disorder patients in the direction of their peers without this disorder.

Implications of Breast Cancer Chemotherapy-Induced Inflammation on the Gut, Liver, and Central Nervous System

Breast Cancer is still one of the most common cancers today; however, with advancements in diagnostic and treatment methods, the mortality and survivorship of patients continues to decrease and increase, respectively. Commonly used treatments today consist of drug combinations, such as doxorubicin and cyclophosphamide; docetaxel, doxorubicin, and cyclophosphamide; or doxorubicin, cyclophosphamide, and paclitaxel. Although these combinations are effective at destroying cancer cells, there is still much to be understood about the effects that chemotherapy can have on normal organ systems such as the nervous system, gastrointestinal tract, and the liver. Patients can experience symptoms of cognitive impairments or “chemobrain”, such as difficulty in concentrating, memory recollection, and processing speed. They may also experience gastrointestinal (GI) distress symptoms such as diarrhea and vomiting, as well as hepatotoxicity and long term liver damage. Chemotherapy treatment has also been shown to induce peripheral neuropathy resulting in numbing, pain, and tingling sensations in the extremities of patients. Interestingly, researchers have discovered that this array of symptoms that cancer patients experience are interconnected and mediated by the inflammatory response.

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

BACKGROUND

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

OBJECTIVE/HYPOTHESIS

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Neuropsychological functioning among patients with different types of cancer : Postchemotherapy cognitive impairment and implications for rehabilitation

BACKGROUND

Chemotherapeutic drugs often contribute to the cognitive impairment observed in some individuals following chemotherapy treatment. Postchemotherapy cognitive impairment (PCCI) is referred to as a decline in a variety of neuropsychological measures after chemotherapy and has an acute onset.

METHODS

The goals of the present study are to compare the manifestation of longitudinal PCCI among 182 patients with four different types of cancer (breast, colorectal, prostate and thyroid cancer) before chemotherapy (T1), immediately after chemotherapy (T2) and 6 months later (T3).

RESULTS

Although no statistically significant differences were observed between the study groups in any of the cognitive domains before chemotherapy, patients with breast cancer showed significantly lower performance on all cognitive domains compared to other patients at the postchemotherapy timepoints.

CONCLUSIONS

Although cognitive difficulties are reported during and after chemotherapy for cancer, it seems that there are differences between different types of cancer. We conclude that it is particularly important to assess and manage these cognitive disorders. Management includes rehabilitation programs that can improve cognitive functions and contribute to changes in brain functions to facilitate this improvement.

Cognitive Rehabilitation for Cognitive Dysfunction after Cancer and Cancer Treatment: Implications for Nursing Practice

OBJECTIVE

To provide an overview of cognitive rehabilitation approaches for cognitive dysfunction after cancer and cancer treatment.

DATA SOURCES

Review and synthesis of empirical articles.

CONCLUSION

Cognitive rehabilitation approaches, including cognitive behavioral therapy and cognitive training, for cognitive dysfunction appear feasible to deliver, satisfactory to participants, and have shown promising results in cancer survivors. Future research is needed to address optimal dose, delivery method, access, cost, and the vulnerable aging cancer survivor population.

IMPLICATIONS FOR NURSING PRACTICE

Oncology nurses must understand the available evidence and be able to provide information and options to cancer survivors to address cognitive changes after cancer.

Cognitive rehabilitation for cancer-related cognitive dysfunction: a systematic review

PURPOSE

Individuals with non-central nervous system (CNS) cancers can experience cancer-related cognitive dysfunction (CRCD), negatively impacting daily functioning and quality of life. This systematic review examined cognitive rehabilitation programs aimed at improving cognitive function.

METHODS

PsychInfo and PubMed were searched in February 2019. Eligible studies evaluated a cognitive rehabilitation program for adults with non-CNS cancers and included at least one objective cognitive measure. Across studies, we assessed methodological quality using relevant criteria based on published intervention-related review guidelines and examined findings from performance-based and self-reported outcome measures.

RESULTS

19 studies met inclusion criteria, totalling 1124 participants altogether. These studies included randomized controlled trials (n = 12), partial, quasi or non-randomized controlled trials (n = 3) and single-arm pilot studies (n = 4). All studies found improvements on at least one cognitive measure (performance-based or self-reported). By cognitive domain, objective improvements in memory were most commonly reported, followed by executive functions and processing speed. In terms of methodological quality, studies generally provided clear descriptions of participants and interventions. However, limitations included lack of standardized terminology for interventions, discrepancies in outcome measures, and incomplete statistical reporting.

CONCLUSIONS

The available evidence supports clinical implementation of cognitive rehabilitation to improve CRCD, with further work in program development, dissemination, and feasibility recommended. We provide specific recommendations to facilitate future research and integration in this field.

Cognitive behavioral therapy for cancer-related cognitive dysfunction

PURPOSE OF REVIEW

To provide the reader with an overview of the cognitive-behavioral conceptualization of cancer-related cognitive dysfunction (CRCD) and how cognitive behavioral therapy (CBT) can play an important role in treatment.

RECENT FINDINGS

Recent findings show that Memory and Attention Adaptation Training (MAAT), a CBT developed to help cancer survivors develop adaptive skills to improve daily cognitive performance and emotional coping, may be an efficacious treatment of CRCD and can be delivered through videoconference technology to improve survivor access to care.

SUMMARY

The etiology of CRCD remains largely undetermined and likely is produced by multiple mechanisms. This can include neuronal death, microvascular damage, inflammatory processes, and psychological factors of perceptions of inadequate cognitive capacity to meet performance demands and related emotional distress. As a result, there are a variety of treatments currently being researched. More research with larger sample sizes, multiple clinicians and multiple sites are needed to confirm efficacy, but CBT approaches such as Memory and Attention Adaptation Training that address multiple psychological factors involved may offer a flexible nonpharmacological approach to CRCD that optimizes quality of life outcomes.

Efficacy of a web-based cognitive rehabilitation intervention for adult cancer survivors: A pilot study

The purpose of this study was to evaluate the efficacy of a web-based cognitive rehabilitation intervention in survivors of adult-onset cancer and a sample of non-cancer community dwelling adults. Fifty-one participants were recruited and allocated to a cancer intervention group, a non-cancer intervention group, or a non-cancer waitlist group. Intervention groups completed a 4-week online program and all participants were assessed at baseline, post-intervention and 3-month follow-up. The primary outcome measure was subjective cognitive functioning. Secondary outcome measures included objective cognitive functioning, distress, quality of life (QoL), illness perception and program satisfaction. Results from the study found significant improvements on self-report measures of cognitive functioning in both treatment groups, as well as improvements on objective measures assessing attention and executive functioning. No intervention effects were observed for distress, QoL or illness perception. High participant satisfaction was observed with 75% of participants in the cancer group reporting being either "satisfied" or "very satisfied" with the program compared to 87% in the non-cancer treatment group. Initial evaluation of the program suggests that the web-based cognitive rehabilitation intervention shows potential for improving subjective and objective cognitive functioning in cancer survivors and community dwelling adults.

What You Do Not Know Could Hurt You: What Women Wish Their Doctors Had Told Them About Chemotherapy Side Effects on Memory and Response to Alcohol

For many patients, a cancer diagnosis is followed by chemotherapy treatment, which works by attacking cells that are growing and dividing throughout the body. Although cancer cells grow and divide more quickly than healthy cells, both are targets. The loss of healthy cells is associated with side effects, such as memory loss and altered response to a variety of food and drugs. In this pilot study, we use the "Survey of female cancer treatments, effects on memory and alcohol awareness" to explore trends in female experience and awareness of side effects associated with chemotherapy. We examined 79 female cancer patients, 46 Spanish-speaking women in Puerto Rico and 33 English-speaking women in the continental United States, and compared the rates of a reported memory loss or an altered ethanol response following chemotherapy, whether or not potential side effects were discussed with a medical professional, and whether they experienced changes in alcohol consumption after treatment. A majority of participants reported having experienced short-term memory loss postchemotherapy. Changes in response to alcohol and an altered sensitivity to alcohol were also reported by 25%-47% of the respondents. Additionally, more than half of all female cancer patients reported that they wished they would have received information on the side effects of chemotherapy and secondary medications prior to treatment. The survey results suggest that medical professionals are not adequately informing women of common, potentially harmful side effects of chemotherapy. Women do wish to be more educated about potential side effects related to memory and alcohol and be given the opportunity to discuss potential outcomes with a medical professional prior to treatment to reduce the negative impact of treatment-related side effects on posttreatment quality of life.

Non-pharmacological interventions for cognitive impairment due to systemic cancer treatment

BACKGROUND

It is estimated that up to 75% of cancer survivors may experience cognitive impairment as a result of cancer treatment and given the increasing size of the cancer survivor population, the number of affected people is set to rise considerably in coming years. There is a need, therefore, to identify effective, non-pharmacological interventions for maintaining cognitive function or ameliorating cognitive impairment among people with a previous cancer diagnosis.

OBJECTIVES

To evaluate the cognitive effects, non-cognitive effects, duration and safety of non-pharmacological interventions among cancer patients targeted at maintaining cognitive function or ameliorating cognitive impairment as a result of cancer or receipt of systemic cancer treatment (i.e. chemotherapy or hormonal therapies in isolation or combination with other treatments).

SEARCH METHODS

We searched the Cochrane Centre Register of Controlled Trials (CENTRAL), MEDLINE, Embase, PUBMED, Cumulative Index of Nursing and Allied Health Literature (CINAHL) and PsycINFO databases. We also searched registries of ongoing trials and grey literature including theses, dissertations and conference proceedings. Searches were conducted for articles published from 1980 to 29 September 2015.

SELECTION CRITERIA

Randomised controlled trials (RCTs) of non-pharmacological interventions to improve cognitive impairment or to maintain cognitive functioning among survivors of adult-onset cancers who have completed systemic cancer therapy (in isolation or combination with other treatments) were eligible. Studies among individuals continuing to receive hormonal therapy were included. We excluded interventions targeted at cancer survivors with central nervous system (CNS) tumours or metastases, non-melanoma skin cancer or those who had received cranial radiation or, were from nursing or care home settings. Language restrictions were not applied.

DATA COLLECTION AND ANALYSIS

Author pairs independently screened, selected, extracted data and rated the risk of bias of studies. We were unable to conduct planned meta-analyses due to heterogeneity in the type of interventions and outcomes, with the exception of compensatory strategy training interventions for which we pooled data for mental and physical well-being outcomes. We report a narrative synthesis of intervention effectiveness for other outcomes.

MAIN RESULTS

Five RCTs describing six interventions (comprising a total of 235 participants) met the eligibility criteria for the review. Two trials of computer-assisted cognitive training interventions (n = 100), two of compensatory strategy training interventions (n = 95), one of meditation (n = 47) and one of physical activity intervention (n = 19) were identified. Each study focused on breast cancer survivors. All five studies were rated as having a high risk of bias. Data for our primary outcome of interest, cognitive function were not amenable to being pooled statistically. Cognitive training demonstrated beneficial effects on objectively assessed cognitive function (including processing speed, executive functions, cognitive flexibility, language, delayed- and immediate- memory), subjectively reported cognitive function and mental well-being. Compensatory strategy training demonstrated improvements on objectively assessed delayed-, immediate- and verbal-memory, self-reported cognitive function and spiritual quality of life (QoL). The meta-analyses of two RCTs (95 participants) did not show a beneficial effect from compensatory strategy training on physical well-being immediately (standardised mean difference (SMD) 0.12, 95% confidence interval (CI) -0.59 to 0.83; I(2)= 67%) or two months post-intervention (SMD - 0.21, 95% CI -0.89 to 0.47; I(2) = 63%) or on mental well-being two months post-intervention (SMD -0.38, 95% CI -1.10 to 0.34; I(2) = 67%). Lower mental well-being immediately post-intervention appeared to be observed in patients who received compensatory strategy training compared to wait-list controls (SMD -0.57, 95% CI -0.98 to -0.16; I(2) = 0%). We assessed the assembled studies using GRADE for physical and mental health outcomes and this evidence was rated to be low quality and, therefore findings should be interpreted with caution. Evidence for physical activity and meditation interventions on cognitive outcomes is unclear.

AUTHORS' CONCLUSIONS

Overall, the, albeit low-quality evidence may be interpreted to suggest that non-pharmacological interventions may have the potential to reduce the risk of, or ameliorate, cognitive impairment following systemic cancer treatment. Larger, multi-site studies including an appropriate, active attentional control group, as well as consideration of functional outcomes (e.g. activities of daily living) are required in order to come to firmer conclusions about the benefits or otherwise of this intervention approach. There is also a need to conduct research into cognitive impairment among cancer patient groups other than women with breast cancer.

Measuring cognitive complaints in breast cancer survivors: psychometric properties of the patient's assessment of own functioning inventory

PURPOSE

Cognitive complaints are a concern for breast cancer survivors. Among various published measures for cognitive complaints, the Patient's Assessment of Own Functioning Inventory (PAOFI) is one of the few assessing a spectrum of cognitive abilities, including those most commonly reported by breast cancer survivors. This study aimed to examine the psychometric properties of the PAOFI in breast cancer survivors.

METHODS

An exploratory factor analysis was conducted with a sample of breast cancer survivors (n = 189) who had completed all primary cancer treatments. Construct validity was examined by correlating factor scores with valid measures of cognitive complaints, fatigue, and quality of life. Reliability was measured by internal consistency of the items in each factor within this sample, a separate sample of breast cancer survivors with high persistent cognitive complaints (n = 72), and healthy controls (n = 63). Factor scores were compared across the three samples.

RESULTS

A five-factor structure similar to the PAOFI standardization study was found, with factors related to executive functioning (accounting for most of the variance), two aspects of memory functioning, language, and motor/sensory-perceptual abilities. Factor scores highly correlated with measures of cognitive complaints, fatigue, and quality of life. Executive functioning and memory-related factors achieved adequate reliability across samples. Scores were significantly different across the three samples as expected.

CONCLUSIONS

The PAOFI is a reliable and valid tool for measuring cognitive complaints in breast cancer survivors.

Impact of Cancer and Its Treatments on Cognitive Function: Advances in Research From the Paris International Cognition and Cancer Task Force Symposium and Update Since 2012

CONTEXT

Although cognitive impairments have been identified in patients with non-central nervous system cancer, especially breast cancer, the respective roles of cancer and therapies, and the mechanisms involved in cognitive dysfunction remain unclear.

OBJECTIVES

To report a state-of-the-art update from the International Cognitive and Cancer Task Force conference held in 2012.

METHODS

A report of the meeting and recent new perspectives are presented.

RESULTS

Recent clinical data support that non-central nervous system cancer per se may be involved in cognitive dysfunctions associated with inflammation parameters. The role of chemotherapy on cognitive decline was confirmed in colorectal and testicular cancers. Whereas the impact of hormone therapy remains debatable, some studies support a negative impact of targeted therapies on cognition. Regarding interventions, preliminary results of cognitive rehabilitation showed encouraging results. The methodology of future longitudinal studies has to be optimized by a priori end points, the use of validated test batteries, and the inclusion of control groups. Comorbidities and aging are important factors to be taken into account in future studies. Preclinical studies in animal models highlighted the role of cancer itself on cognition and support the possible benefits of prevention/care during chemotherapy. Progress in neuroimaging will help specify neural processes affected by treatments.

CONCLUSION

Clinical data and animal models confirmed that chemotherapy induces direct cognitive deficit. The benefits of cognitive rehabilitation are still to be confirmed. Studies evaluating the mechanisms underlying cognitive impairments using advanced neuroimaging techniques integrating the evaluation of genetic factors are ongoing.

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.

Therapies for Cognitive Deficits Associated With Chemotherapy for Breast Cancer: A Systematic Review of Objective Outcomes

OBJECTIVE

To systematically review evidence of treatments for cognitive impairments experienced by at least 20% of all women who undergo chemotherapy for breast cancer.

DATA SOURCES

Searches of 5 databases (PubMed, Embase, Cochrane CENTRAL, PsycINFO, CINAHL), with no date or language restrictions, identified 1701 unique results. Search terms included breast cancer, chemotherapy, chemobrain, chemofog, and terms on cognition and language deficits.

STUDY SELECTION

Included only peer-reviewed journal articles that described therapies for cognitive dysfunction in women undergoing (or who had undergone) chemotherapy for breast cancer and provided objective measurements of cognition or language.

DATA EXTRACTION

Data were extracted according to Cochrane recommendations, including characteristics of participants, interventions, outcomes, and studies. Quality assessment of all 12 eligible studies was performed using the Physiotherapy Evidence Database scale and treatment fidelity criteria. Screening, data extraction, and quality assessment reliability were performed.

DATA SYNTHESIS

Six articles described interventions for cognition that took place during cancer treatment; 6, afterward. Five interventions were medical (including a strength-training program), 2 were restorative, and 5 were cognitive. Medicinal treatments were ineffective; restorative and exercise treatments had mixed results; cognitive therapy had success in varying cognitive domains. The domains most tested and most successfully treated were verbal memory, attention, and processing speed.

CONCLUSIONS

Cognitive therapy protocols delivered after chemotherapy and aimed at improving verbal memory, attention, and processing speed hold the most promise. Future research is needed to clarify whether computerized cognitive training can be effective in treating this population, and to identify objective assessment tools that are sensitive to this disorder.

Psychological intervention for improving cognitive function in cancer survivors: a literature review and randomized controlled trial

Although the impact of cancer and associated treatments on cognitive functioning is becoming an increasingly recognized problem, there are few published studies that have investigated psychological interventions to address this issue. A waitlist randomized controlled trial methodology was used to assess the efficacy of a group cognitive rehabilitation intervention ("ReCog") that successfully targeted cancer-related cognitive decline in previously published pilot research. Participants were 29 cancer survivors who were randomly allocated to either the intervention group or a waitlist group who received the intervention at a later date, and 16 demographically matched community volunteers with no history of cancer (trial registration ACTRN12615000009516, available at http://www.ANZCTR.org.au/ACTRN12615000009516.aspx). The study was the first to include an adapted version of the Traumatic Brain Injury Self-Efficacy Scale to assess cognitive self-efficacy (CSE) in people who have experienced cancer. Results revealed participating in the intervention was associated with significantly faster performance on one objective cognitive task that measures processing speed and visual scanning. Significantly larger improvements for the intervention group were also found on measures of perceived cognitive impairments and CSE. There was some evidence to support the roles of CSE and illness perceptions as potential mechanisms of change for the intervention. Overall, the study provided additional evidence of feasibility and efficacy of group psychological intervention for targeting cancer-related cognitive decline.

Clinical characteristics, pathophysiology, and management of noncentral nervous system cancer-related cognitive impairment in adults

Answer questions and earn CME/CNE Over the past few decades, a body of research has emerged confirming what many adult patients with noncentral nervous system cancer have long reported-that cancer and its treatment are frequently associated with cancer-related cognitive impairment (CRCI). The severity of CRCI varies, and symptoms can emerge early or late in the disease course. Nonetheless, CRCI is typically mild to moderate in nature and primarily involves the domains of memory, attention, executive functioning, and processing speed. Animal models and novel neuroimaging techniques have begun to unravel the pathophysiologic mechanisms underlying CRCI, including the role of inflammatory cascades, direct neurotoxic effects, damage to progenitor cells, white matter abnormalities, and reduced functional connectivity, among others. Given the paucity of research on CRCI with other cancer populations, this review synthesizes the current literature with a deliberate focus on CRCI within the context of breast cancer. A hypothetical case-study approach is used to illustrate how CRCI often presents clinically and how current science can inform practice. While the literature regarding intervention for CRCI is nascent, behavioral and pharmacologic approaches are discussed.

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.

Consequences of cancer treatments on adult hippocampal neurogenesis: implications for cognitive function and depressive symptoms

The human brain is capable of generating new functional neurons throughout life, a phenomenon known as adult neurogenesis. The generation of new neurons is sustained throughout adulthood due to the proliferation and differentiation of adult neural stem cells. This process in humans is uniquely located in the subgranular zone of the dentate gyrus in the hippocampus. Adult hippocampal neurogenesis (AHN) is thought to play a major role in hippocampus-dependent functions, such as spatial awareness, long-term memory, emotionality, and mood. The overall aim of current treatments for cancer (such as radiotherapy and chemotherapy) is to prevent aberrant cell division of cell populations associated with malignancy. However, the treatments in question are absolutist in nature and hence inhibit all cell division. An unintended consequence of this cessation of cell division is the impairment of adult neural stem cell proliferation and AHN. Patients undergoing treatment for cancerous malignancies often display specific forms of memory deficits, as well as depressive symptoms. This review aims to discuss the effects of cancer treatments on AHN and propose a link between the inhibition of the neurogenetic process in the hippocampus and the advent of the cognitive and mood-based deficits observed in patients and animal models undergoing cancer therapies. Possible evidence for coadjuvant interventions aiming to protect neural cells, and subsequently the mood and cognitive functions they regulate, from the ablative effects of cancer treatment are discussed as potential clinical tools to improve mental health among cancer patients.

Neuroimaging biomarkers and cognitive function in non-CNS cancer and its treatment: current status and recommendations for future research

Cognitive changes in patients undergoing treatment for non-central nervous system (CNS) cancers have been recognized for several decades, yet the underlying mechanisms are not well understood. Structural, functional and molecular neuroimaging has the potential to help clarify the neural bases of these cognitive abnormalities. Structural magnetic resonance imaging (MRI), functional MRI (fMRI), diffusion tensor imaging (DTI), MR spectroscopy (MRS), and positron emission tomography (PET) have all been employed in the study of cognitive effects of cancer treatment, with most studies focusing on breast cancer and changes thought to be induced by chemotherapy. Articles in this special issue of Brain Imaging and Behavior are devoted to neuroimaging studies of cognitive changes in patients with non-CNS cancer and include comprehensive critical reviews and novel research findings. The broad conclusions that can be drawn from past studies and the present body of new research is that there are structural and functional changes associated with cancer and various treatments, particularly systemic cytotoxic chemotherapy, although some cognitive and fMRI studies have identified changes at pre-treatment baseline. Recommendations to accelerate progress include well-powered multicenter neuroimaging studies, a better standardized definition of the cognitive phenotype and extension to other cancers. A systems biology framework incorporating multimodality neuroimaging, genetics and other biomarkers will be highly informative regarding individual differences in risk and protective factors and disease- and treatment-related mechanisms. Studies of interventions targeting cognitive changes are also needed. These next steps are expected to identify novel protective strategies and facilitate a more personalized medicine for cancer patients.