Evaluation of Cognitive Function Associated With Chemotherapy: A Review of Published Studies and Recommendations for Future Research

The cancer chemotherapeutic agent paclitaxel (Taxol) reduces hippocampal neurogenesis via down-regulation of vesicular zinc

Chemotherapy-induced cognitive impairment (CICI) is increasingly recognized as a major unwanted side effect of an otherwise highly valuable life-saving technology. In part, this awareness is a result of increased cancer survival rates following chemotherapy. Altered hippocampal neurogenesis may play a role in mediating CICI. In particular, zinc could act as a key regulator of this process. To test this hypothesis, we administered paclitaxel (Px) to male C57BL/6 mice for set time periods and then evaluated the effects of Px treatment on hippocampal neurogenesis and vesicular zinc. We found that vesicular zinc levels and expression of zinc transporter 3 (ZnT3) were reduced in Px-treated mice, compared to vehicle-treated mice. Moreover, Px-treated mice demonstrated a significant decrease in the number of neuroblasts present. However, no difference in the number of progenitor cells were observed. In addition, zinc supplementation by treatment with ZnCl₂ ameliorated the Px-induced decrease in hippocampal neurogenesis and cognitive impairment. These results suggest that via disruption of vesicular zinc stores in hippocampal mossy fiber terminals, chemotherapy may impinge upon one or more of the sequential stages involved in the maturation of new neurons derived via adult neurogenesis and thereby leads to the progressive cognitive decline associated with CICI.

Chemotherapy and Post-traumatic Stress in the Causation of Cognitive Dysfunction in Breast Cancer Patients

Background

Cancer-related cognitive dysfunction has mostly been attributed to chemotherapy; this explanation, however, fails to account for cognitive dysfunction observed in chemotherapy-naïve patients. In a controlled, longitudinal, multisite study, we tested the hypothesis that cognitive function in breast cancer patients is affected by cancer-related post-traumatic stress.

Methods

Newly diagnosed breast cancer patients and healthy control subjects, age 65 or younger, underwent three assessments within one year, including paper-and-pencil and computerized neuropsychological tests, clinical diagnostics of post-traumatic stress disorder (PTSD), and self-reported cognitive function. Analysis of variance was used to compare three groups of participants-patients who did or did not receive chemotherapy and healthy control subjects-on age- and education-corrected cognitive performance and cognitive change. Differences that were statistically significant after correction for false discovery rate were investigated with linear mixed-effects models and mediation models. All statistical tests were two-sided.

Results

Of 226 participants (166 patients and 60 control subjects), 206 completed all assessment sessions (attrition: 8.8%). Patients demonstrated overall cognitive decline (group*time effect on composite z -score: -0.13, P = .04) and scored consistently worse on Go/Nogo errors. The latter effect was mediated by PTSD symptoms (mediation effect: B = 0.15, 95% confidence interval = 0.02 to 0.38). Only chemotherapy patients showed declined reaction time on a computerized alertness test. Overall cognitive performance correlated with self-reported cognitive problems at one year ( T = -0.11, P = .02).

Conclusions

Largely irrespective of chemotherapy, breast cancer patients may encounter very subtle cognitive dysfunction, part of which is mediated by cancer-related post-traumatic stress. Further factors other than treatment side effects remain to be investigated.

Effects of long-term androgen deprivation therapy on cognitive function over 36 months in men with prostate cancer

BACKGROUND

Many men with prostate cancer (PC) require long-term androgen deprivation therapy (ADT), but to the authors' knowledge, its effects on cognitive function beyond 1 year are not described.

METHODS

Three groups of men aged ≥50 years who were matched based on age and education were enrolled: 77 patients with nonmetastatic PC who initiated continuous ADT, 82 patients with PC who were not receiving ADT (PC controls), and 82 healthy controls. A battery of 14 neuropsychological tests, examining 8 cognitive domains, was administered on 5 occasions over 36 months. Changes in cognitive scores over time were analyzed using 3 approaches: linear mixed effects regression, the percentage of participants per group with declines in ≥1/2 cognitive tests, and a global summary of cognitive change.

RESULTS

The mean age of the study subjects was 68.9 years, with a median of 16 years of education. In mixed effects models adjusted for age and education, ADT use was not found to be associated with significant changes over time in any cognitive test compared with healthy controls. The percentage of participants declining by ≥1.5 standard deviations in ≥2 tests or ≥2 standard deviations in ≥1 tests was similar across groups. A global summary of cognitive change found no statistically significant worsening of cognitive function among ADT users compared with controls. Sensitivity analyses adjusting for duration of ADT and using multiple imputation for missing data did not materially alter the study findings.

CONCLUSIONS

The ongoing use of ADT for up to 36 months does not appear to be associated with cognitive decline. Cancer 2017;123:237-244. © 2016 American Cancer Society.

Evolution of Sex Differences in Trait- and Age-Specific Vulnerabilities

Traits that facilitate competition for reproductive resources or that influence mate choice generally have a heightened sensitivity to stressors. They have evolved to signal resilience to infectious disease and nutritional and social stressors, and they are compromised by exposure to man-made toxins. Although these traits can differ from one species or sex to the next, an understanding of the dynamics of competition and choice can in theory be used to generate a priori predictions about sex-, age-, and trait-specific vulnerabilities for any sexually reproducing species. I provide a review of these dynamics and illustrate associated vulnerabilities in nonhuman species. The age- and sex-specific vulnerability of such traits is then illustrated for stressor-related disruptions of boys’ and girls’ physical growth and play behavior, as well as for aspects of boys’ and girls’ and men’s and women’s personality, language, and spatial abilities. There is much that remains to be determined, but enough is now known to reframe trait sensitivity in ways that will allow scientists and practitioners to better identify and understand vulnerable human traits, and eventually ameliorate or prevent their expression.

Viruses as nanomedicine for cancer

Oncolytic virotherapy, a type of nanomedicine in which oncolytic viruses (OVs) are used to selectively infect and lyse cancer cells, is an emerging field in cancer therapy. Some OVs exhibit a specific tropism for cancer cells, whereas others require genetic modification to enhance their binding with and entry into cancer cells. OVs both kill tumor cells and induce the host’s immune response against tumor cells. Armed with antitumor cellular molecules, antibodies, and/or in combination with anticancer drugs, OVs can accelerate the lysis of cancer cells. Among the OVs, vaccinia virus has been the focus of preclinical and clinical research because of its many favorable properties. In this review, the basic mechanisms of action of OVs are presented, including their entry, survival, tumor lysis, and immune activation, and the latest research in vaccinia virus-based virotherapy and its status as an anticancer nanomedicine in prospective clinical trials are discussed.

Long-lasting impairments in adult neurogenesis, spatial learning and memory from a standard chemotherapy regimen used to treat breast cancer

The negative impact of chemotherapy on cognitive function in cancer patients has gained increasing attention in the last decade. Whilst the short-term acute effects on cognition are expected following chemotherapy, the persistence of such impairments in the long-term is still in question. This is despite clinical evidence indicating cognitive difficulties may persist well beyond treatment and affect quality of life. In the present study, we assessed the long-term (3 months) cognitive impact of chemotherapy in a mouse model intended to mimic the human female post-menopausal population receiving chemotherapy for breast cancer. Ovariectomized, female, C57BL/6J mice received two doses of Doxorubicin, Cyclophosphamide, and 5-Fluorouracil or saline vehicle (control), separated by one week. During this interval, mice received BrdU injections to label dividing cells. Results indicate a persistent impairment in learning and recall (1h, 24h and 48h) on the Morris water maze, reduced survival and differentiation of new neurons (BrdU+/NeuN+), and a persistent decline in proliferation of new cells (Ki67(+)) in the dentate gyrus. Locomotor activity, motor performance, and anxiety-like behavior were unaffected. We further evaluated the efficacy of a diet enriched in omega-3-fatty acids (DHA+EPA+DPA), in reversing long-term chemotherapy deficits but no rescue was observed. The model described produces long-term cognitive and cellular impairments from chemotherapy that mimic those observed in humans. It could be useful for identifying mechanisms of action and to test further the ability of lifestyle interventions (e.g., diet) for ameliorating chemotherapy-induced cognitive impairments.

A clinically relevant dose of cyclophosphamide chemotherapy impairs memory performance on the delayed spatial alternation task that is sustained over time as mice age

BACKGROUND

Cyclophosphamide chemotherapy is a mainstay of adjuvant breast cancer treatment. Unfortunately, this drug is associated with cognitive impairments in cancer patients that may accelerate cognitive aging. Memory is particularly affected in many patients. In order to better understand the precise cognitive impairments caused by this chemotherapy agent, we investigated a clinically relevant dose and administration paradigm on delayed spatial memory abilities in C57BL/6 mice. We utilized a delayed alternation paradigm similar to a delayed match to sample paradigm reported to be sensitive in human neurotoxicology research.

METHODS

A dose of 200mg/kg cyclophosphamide was administered intravenously (at weekly intervals) for 4 weeks to C57BL/6 mice starting at 6 ½ months of age. Memory was tested in mice using a reward-based delayed spatial alternation paradigm with delay values of 1.5, 3, 6.1, 12.4 and 25s presented randomly over 80 sessions (16 reinforcers per session), and testing began at the initiation of chemotherapy through 3 months.

RESULTS

At the longest delay, i.e., that requiring the greatest memory, mice treated with chemotherapy exhibited a significant decline over time in percent correct which leveled off compared to controls that continued to improve slightly.

CONCLUSIONS

Our clinically relevant model shows cyclophosphamide chemotherapy causes a slight decline in delayed spatial memories at the longest delay that is sustained over time as mice age.

The perceptions of Australian oncologists about cognitive changes in cancer survivors

OBJECTIVE

Cancer-related cognitive changes (CRCC) can have a profound impact on a cancer survivor's quality of life. However, cancer survivors frequently report receiving limited information about their experience of CRCC from their oncology specialists. This qualitative study aimed to explore the perceptions of oncology specialists regarding CRCC and the potential for their views to influence their decisions about patient care.

METHODS

Thirteen medical oncologists and five radiation oncologists currently practising in Australia participated in this study. Data collection involved individual semi-structured interviews via telephone. Data were audio-recorded, transcribed verbatim and analysed using a thematic approach.

RESULTS

Four key themes emerged: (1) beliefs about the impact of priming on cancer survivors' perceived cognitive function, (2) perceptions of who is more likely to raise concerns of cognitive change, (3) uncertainty of how to best manage CRCC, and (4) the perceived role of oncologists in the management of CRCC.

CONCLUSIONS

CRCC and its impact on the cancer survivor's journey have been under-addressed by oncology specialists, and they are uncertain of potential management strategies. With cancer survival rates increasing, there is a need for specific interventions and management guidelines addressing CRCC and their effects on cancer survivors. Future exploration should focus on the survivor as central to their care and holistic approaches to CRCC management involving all members of the multidisciplinary team.

Randomized controlled pilot trial of mindfulness-based stress reduction for breast and colorectal cancer survivors: effects on cancer-related cognitive impairment

PURPOSE

Cancer-related cognitive impairment (CRCI) is a common, fatigue-related symptom that disrupts cancer survivors' quality of life. Few interventions for CRCI exist. As part of a randomized pilot study targeting cancer-related fatigue, the effects of mindfulness-based stress reduction (MBSR) on survivors' cognitive outcomes were investigated.

METHODS

Breast and colorectal cancer survivors (n = 71) with moderate-to-severe fatigue were randomized to MBSR (n = 35) or a fatigue education and support (ES; n = 36) condition. The Attentional Function Index (AFI) and the Stroop test were used to assess survivors' cognitive function at baseline (T1), after the 8-week intervention period (T2), and 6 months later (T3) using intent-to-treat analysis. Mediation analyses were performed to explore mechanisms of intervention effects on cognitive functioning.

RESULTS

MBSR participants reported significantly greater improvement on the AFI total score compared to ES participants at T2 (d = 0.83, p = 0.001) and T3 (d = 0.55, p = 0.021). MBSR also significantly outperformed ES on most AFI subscales, although both groups improved over time. MBSR produced greater Stroop accuracy rates relative to ES at T2 (r = 0.340, p = 0.005) and T3 (r = 0.280, p = 0.030), with improved accuracy over time only for the MBSR group. There were no significant differences in Stroop reaction time between groups. Improvements in mindfulness mediated the effect of group (e.g., MBSR vs. ES) on AFI total score at T2 and T3.

CONCLUSIONS

Additional randomized trials with more comprehensive cognitive measures are warranted to definitively assess the efficacy of MBSR for CRCI.

IMPLICATIONS FOR CANCER SURVIVORS

This pilot study has important implications for all cancer survivors as it is the first published trial to show that MBSR offers robust and durable improvements in CRCI.

Assessing cognitive function in adults during or following chemotherapy: a scoping review

PURPOSE

The purpose of this scoping review was to determine the feasibility of conducting a systematic review of approaches for screening or assessing cognitive function that were comprehensive and that could be incorporated into clinical settings.

METHODS

Using the scoping review approach developed by Arksey and O'Malley, we searched Ovid Embase 1980-, Ovid PsycINFO 1806-, Ovid Health and Psychosocial Instruments 1985-, EBSCOhost CINAHL, ISI Web of Science (Science Citation Index 1900-), Social Sciences Citation Index 1900-, Conference Proceedings Citation Index -Science 1990-, Conference Proceedings Citation Index -Social Science & Humanities 1990-, Scopus 1960-, with no language restrictions. Searches were conducted in April 2009 and updated in February 2013. Studies of adults treated with chemotherapy that included at least seven of the eight domains of cognition were included.

RESULTS

Eleven studies met inclusion criteria. No screening tools suitable for inclusion in a clinic were identified. The studies reviewed varied by inclusion/exclusion criteria, design, and instruments for assessing cognitive function, and thus, there are not yet enough studies to warrant a systematic review on this topic.

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.

PAN-811 Blocks Chemotherapy Drug-Induced In Vitro Neurotoxicity, While Not Affecting Suppression of Cancer Cell Growth

Chemotherapy often results in cognitive impairment, and no neuroprotective drug is now available. This study aimed to understand underlying neurotoxicological mechanisms of anticancer drugs and to evaluate neuroprotective effects of PAN-811. Primary neurons in different concentrations of antioxidants (AOs) were insulted for 3 days with methotrexate (MTX), 5-fluorouracil (5-FU), or cisplatin (CDDP) in the absence or presence of PAN-811·Cl·H₂O. The effect of PAN-811 on the anticancer activity of tested drugs was also examined using mouse and human cancer cells (BNLT3 and H460) to assess any negative interference. Cell membrane integrity, survival, and death and intramitochondrial reactive oxygen species (ROS) were measured. All tested anticancer drugs elicited neurotoxicity only under low levels of AO and elicited a ROS increase. These results suggested that ROS mediates neurotoxicity of tested anticancer drugs. PAN-811 dose-dependently suppressed increased ROS and blocked the neurotoxicity when neurons were insulted with a tested anticancer drug. PAN-811 did not interfere with anticancer activity of anticancer drugs against BNLT3 cells. PAN-811 did not inhibit MTX-induced death of H460 cells but, interestingly, demonstrated a synergistic effect with 5-FU or CDDP in reducing cancer cell viability. Thus, PAN-811 can be a potent drug candidate for chemotherapy-induced cognitive impairment.

Cognitive Function in Patients With Colorectal Cancer Who Do and Do Not Receive Chemotherapy: A Prospective, Longitudinal, Controlled Study

PURPOSE

Cognitive dysfunction is reported in people with cancer. Therefore, we evaluated longitudinal changes in cognitive function and underlying mechanisms in people with colorectal cancer (CRC) and healthy controls (HCs).

PATIENTS AND METHODS

Participants completed cognitive assessments and questionnaires reporting cognitive symptoms, fatigue, quality of life, and anxiety/depression at baseline (before chemotherapy, if given) and 6, 12, and 24 months. Blood tests included cytokines, clotting factors, apolipoprotein E genotype, and sex hormones. Primary end point was overall cognitive function measured by the Global Deficit Score at 12 months.

RESULTS

We recruited 289 patients with localized CRC (173 received chemotherapy; median age, 59 years; 63% male), 73 patients with limited metastatic/recurrent CRC, and 72 HCs. Cognitive impairment was more frequent in patients with localized CRC than HCs at baseline (43% v 15%, respectively; P < .001) and 12 months (46% v 13%, respectively; P < .001), with no significant effect of chemotherapy. Attention/working memory, verbal learning/memory, and complex processing speed were most affected. Cognitive impairment was similar in patients with localized and metastatic CRC. Cytokine levels were elevated in patients with CRC compared with HCs. There was no association between overall cognitive function and fatigue, quality of life, anxiety/depression, or any blood test. Cognitive symptoms at 12 months were reported in 25% of patients with localized CRC versus 17% of HCs (P = .19). More participants who received chemotherapy had cognitive symptoms at 6 months (32%) versus those who did not (16%; P = .007), with no significant difference at 12 months (29% v 21%, respectively; P = .19). Objective cognitive function was only weakly associated with cognitive symptoms.

CONCLUSION

Patients with CRC had substantially more cognitive impairment at every assessment than HCs, with no significant added effect of chemotherapy. Mechanisms of cognitive impairment remain unknown.

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.

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.

Promising oncolytic agents for metastatic breast cancer treatment

New therapies for metastatic breast cancer patients are urgently needed. The long-term survival rates remain unacceptably low for patients with recurrent disease or disseminated metastases. In addition, existing therapies often cause a variety of debilitating side effects that severely impact quality of life. Oncolytic viruses constitute a developing therapeutic modality in which interest continues to build due to their ability to spare normal tissue while selectively destroying tumor cells. A number of different viruses have been used to develop oncolytic agents for breast cancer, including herpes simplex virus, adenovirus, vaccinia virus, measles virus, reovirus, and others. In general, clinical trials for several cancers have demonstrated excellent safety records and evidence of efficacy. However, the impressive tumor responses often observed in preclinical studies have yet to be realized in the clinic. In order for the promise of oncolytic virotherapy to be fully realized for breast cancer patients, effectiveness must be demonstrated in metastatic disease. This review provides a summary of oncolytic virotherapy strategies being developed to target metastatic breast cancer.

Association of proinflammatory cytokines and chemotherapy-associated cognitive impairment in breast cancer patients: a multi-centered, prospective, cohort study

BACKGROUND

Existing evidence suggests that proinflammatory cytokines play an intermediary role in postchemotherapy cognitive impairment. This is one of the largest multicentered, cohort studies conducted in Singapore to evaluate the prevalence and proinflammatory biomarkers associated with cognitive impairment in breast cancer patients.

PATIENTS AND METHODS

Chemotherapy-receiving breast cancer patients (stages I-III) were recruited. Proinflammatory plasma cytokines concentrations [interleukin (IL)-1β, IL-2, IL-4, IL-6, IL-8, IL-10, granulocyte-macrophage colony-stimulating factor, interferon-γ and tumor necrosis factor-α] were evaluated at 3 time points (before chemotherapy, 6 and 12 weeks after chemotherapy initiation). The FACT-Cog (version 3) was utilized to evaluate patients' self-perceived cognitive disturbances and a computerized neuropsychological assessment (Headminder) was administered to evaluate patients' memory, attention, response speed and processing speed. Changes of cognition throughout chemotherapy treatment were compared against the baseline. Linear mixed-effects models were applied to test the relationships of clinical variables and cytokine concentrations on self-perceived cognitive disturbances and each objective cognitive domain.

RESULTS

Ninety-nine patients were included (age 50.5 ± 8.4 years; 81.8% Chinese; mean duration of education = 10.8 ± 3.3 years). Higher plasma IL-1β was associated with poorer response speed performance (estimate: -0.78; 95% confidence interval (CI) -1.34 to -0.03; P = 0.023), and a higher concentration of IL-4 was associated with better response speed performance (P = 0.022). Higher concentrations of IL-1β and IL-6 were associated with more severe self-perceived cognitive disturbances (P = 0.018 and 0.001, respectively). Patients with higher concentrations of IL-4 also reported less severe cognitive disturbances (P = 0.022).

CONCLUSIONS

While elevated concentrations of IL-6 and IL-1β were observed in patients with poorer response speed performance and perceived cognitive disturbances, IL-4 may be protective against chemotherapy-associated cognitive impairment. This study is important because cytokines would potentially be mechanistic mediators of chemotherapy-associated cognitive changes.

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.

Is Cancer a Risk Factor for Cognitive Decline in Late Life?

With advances in screening and early detection, coupled with improved treatment and care, the number of cancer survivors has risen exponentially over the past several decades. Moreover, because age is the most significant risk factor for cancer, the majority of cancer survivors are over 65 years of age. Finally, cancer survivors often experience significant health issues for many years after the treatment has subsided. In the current article, we describe select research that has focused on changes to cognitive performance associated with cancer and its treatment, i.e., alterations that have been colloquially referred to as chemobrain. Although understanding changes in cognitive performance following cancer treatment is an active area of inquiry, the experience of older adult cancer survivors has been somewhat neglected. For example, evidence is mixed as to whether changes in cognitive performance associated with normal aging are exacerbated by cancer survivorship status. It is also unclear whether a history of cancer makes it more or less likely that a person will be diagnosed with dementia or Alzheimer's disease in the future. Finally, we identify a number of areas where existing cognitive aging research can inform studies on cognitive performance following cancer treatment. Future efforts should be directed towards designing studies that focus on the experience of older adult cancer survivors and are informed by the clinical oncology and cognitive aging literature.

Systemic chemotherapy decreases brain glucose metabolism

Objective

Cancer patients may experience neurologic adverse effects, such as alterations in neurocognitive function, as a consequence of chemotherapy. The mechanisms underlying such neurotoxic syndromes remain poorly understood. We here describe the temporal and regional effects of systemically administered platinum-based chemotherapy on glucose metabolism in the brain of cancer patients.

Methods

Using sequential FDG-PET/CT imaging prior to and after administration of chemotherapy, we retrospectively characterized the effects of intravenously administered chemotherapy on brain glucose metabolism in a total of 24 brain regions in a homogenous cohort of 10 patients with newly diagnosed non-small-cell lung cancer.

Results

Significant alterations of glucose metabolism were found in response to chemotherapy in all gray matter structures, including cortical structures, deep nuclei, hippocampi, and cerebellum. Metabolic changes were also notable in frontotemporal white matter (WM) network systems, including the corpus callosum, subcortical, and periventricular WM tracts.

Interpretation

Our data demonstrate a decrease in glucose metabolism in both gray and white matter structures associated with chemotherapy. Among the affected regions are those relevant to the maintenance of brain plasticity and global neurologic function. This study potentially offers novel insights into the spatial and temporal effects of systemic chemotherapy on brain metabolism in cancer patients.

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.

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

To assess the feasibility of a cognitive rehabilitation program in breast cancer survivors (BCS) with persistent post-treatment cognitive complaints. BCS with cognitive complaints, 18-months to 5-years post-treatment, were recruited for a once-weekly, five-week, group cognitive training intervention. Outcome measures included self-reported mood and cognitive function, and neurocognitive tests administered at pre-intervention, immediate-, two-month and four-month post-intervention. A sub-study in eight participants evaluated resting state quantitative electroencephalography (qEEG) changes from pre- to immediate post-intervention in relationship to post-intervention changes in cognitive complaints. Twenty-seven BCS completed the protocol and tolerated the intervention well. We observed significant reductions in total and memory-specific cognitive complaints from pre-intervention to immediate post-intervention (p = 0.031 and p = 0.009, respectively) and at four-months post-intervention (p < 0.0001 and p < 0.001, respectively). Significant improvement in neurocognitive tests were found for Symbol Digit, Stroop, and Trails A tests (df = 26, all p's <0.05). Effect sizes for changes from pre-intervention to immediate and to four-month post intervention ranged from 0.429 to 0.607, and from 0.439 to 0.741, respectively. Increase in qEEG absolute alpha power over the course of the intervention was associated with reduced complaints at immediate post-intervention (r = -0.78, p = 0.021), two-months (r range = -0.76 to -0.82, p-value range 0.004 to 0.03), and four-months (r = -0.71, p = 0.048). A five-week group cognitive training intervention is feasible and well tolerated. Cognitive complaints and neurocognitive test performances showed positive changes. qEEG may serve as a potential biomarker for improvement in self-reported complaints. A randomized clinical trial is underway to test the efficacy of the intervention.

Developing interventions for cancer-related cognitive dysfunction in childhood cancer survivors

Survivors of childhood cancer frequently experience cancer-related cognitive dysfunction, commonly months to years after treatment for pediatric brain tumors, acute lymphoblastic leukemia (ALL), or tumors involving the head and neck. Risk factors for cancer-related cognitive dysfunction include young age at diagnosis, treatment with cranial irradiation, use of parenteral or intrathecal methotrexate, female sex, and pre-existing comorbidities. Limiting use and reducing doses and volume of cranial irradiation while intensifying chemotherapy have improved survival and reduced the severity of cognitive dysfunction, especially in leukemia. Nonetheless, problems in core functional domains of attention, processing speed, working memory and visual-motor integration continue to compromise quality of life and performance. We review the epidemiology, pathophysiology and assessment of cancer-related cognitive dysfunction, the impact of treatment changes for prevention, and the broad strategies for educational and pharmacological interventions to remediate established cognitive dysfunction following childhood cancer. The increased years of life saved after childhood cancer warrants continued study toward the prevention and remediation of cancer-related cognitive dysfunction, using uniform assessments anchored in functional outcomes.

Long-term cognitive function change among breast cancer survivors

Cognitive decline is a common health problem among breast cancer patients and understanding trajectories of cognitive change following among breast cancer survivors is an important public health goal. We conducted a longitudinal study to investigate the cognitive function changes from 18 month to 3 years after breast cancer diagnosis among participants of the Shanghai Breast cancer survivor study, a population-based cohort study of breast cancer survivors. In our study, we completed cognitive function evaluation for 1,300 breast cancer survivors at the 18th month's survey and 1,059 at 36th month's survey, respectively, using a battery of cognitive function measurements. We found the scores in attention and executive function, immediate memory and delayed memory significantly improved from 18 to 36 months after breast cancer diagnosis. The improvements appeared in breast cancer survivors receiving treatments (i.e., surgery, radiotherapy, tamoxifen, or chemotherapy combined with or without tamoxifen), but not in those who received neither chemotherapy nor tamoxifen treatment. The results indicate that cognitive functions, particularly immediate verbal episodic memory, and delayed memory significantly improved among breast cancer survivors from 18 to 36 months after cancer diagnosis. In general, comorbidity was inversely associated with the improvements.

Decision-making impairments in breast cancer patients treated with tamoxifen

The selective estrogen receptor modulator tamoxifen (TAM) is most commonly prescribed for patients with hormone-sensitive breast cancer. Although TAM can bind to estrogen receptors in the nervous system, it is unknown whether it acts as an estrogen agonist or antagonist in the human brain. Several studies have reported the negative effects of TAM on cognitive function; however, its effects on decision-making function have not been previously explored. The present study aimed to investigate the decision-making function under ambiguity and risk in breast cancer patients treated with TAM. Participants included breast cancer patients taking TAM (TAM, n=47) and breast cancer patients not taking TAM (non-TAM, n=45) as well as their matched healthy controls (HC, n=50). All participants were given the Iowa Gambling Task (IGT) to assess their decision-making under conditions involving ambiguity, the Game of Dice Task (GDT) to assess their decision-making under conditions involving risk, and a battery of neuropsychological tests. Our results indicated that patients in the TAM group were significantly impaired as assessed by both the IGT and GDT and performed significantly worse on some aspects of various tasks involving memory and information processing. Furthermore, we found that decreased performance on verbal memory testing significantly correlated with IGT performance, and executive dysfunction was associated with poor GDT performance in breast cancer patients undergoing TAM treatment. This study demonstrates that breast cancer patients taking TAM have several decision-making impairments. These findings may support the idea that TAM resulting in cognitive changes plays an antagonistic role in the areas of the brain where estrogen receptors are present, including the prefrontal cortex, hippocampus and amygdala.

Physical exercise prevents suppression of hippocampal neurogenesis and reduces cognitive impairment in chemotherapy-treated rats

RATIONALE

Chemotherapy, used for the treatment of cancer, often produces cognitive impairment that has been related to suppression of neurogenesis. Physical exercise, which promotes neurogenesis, is known to improve cognitive function in neurologically challenged animals and humans. It is unknown whether exercise similarly protects against chemotherapy-induced cognitive impairment and whether recovery of neurogenesis is a critical factor.

OBJECTIVE

The present study investigated the relationship between hippocampal neurogenesis and cognitive performance in chemotherapy-treated rats that engaged in different amounts of physical activity.

METHODS

Groups of rats, housed individually in standard cages or in specially designed cages that allowed unlimited access to a running wheel, received three injections of the chemotherapeutic drugs methotrexate and 5-fluorouracil, or equal volumes of saline. They were then administered the following cognitive tests in a water maze: (1) spatial memory (SM), (2) cued memory, (3) non-matching to sample (NMTS) rule learning; (4) delayed NMTS (DNMTS). Hippocampal neurogenesis was quantified by counting doublecortin-expressing cells in the dentate gyrus.

RESULTS

Chemotherapy administered to rats in standard cages resulted in a significant reduction in hippocampal neurogenesis and impaired performance on the SM, NMTS, and DNMTS tasks. In rats receiving chemotherapy and housed in exercise cages, neurogenesis was not suppressed and cognitive performance was similar to controls.

CONCLUSIONS

Physical exercise can reduce cognitive deficits that result from chemotherapy and this effect is mediated, at least in part, by preventing suppression of drug-induced hippocampal neurogenesis. The results suggest benefits of exercise in preventing or treating cognitive impairment associated with chemotherapy.

Selective impairment of attention networks in breast cancer patients receiving chemotherapy treatment

INTRODUCTION

Complaints about attention disorders are common among breast cancer survivors who have undergone chemotherapy treatment. However, it is not known whether these complaints indicate a global attention deficit or the selective impairment of attention networks.

OBJECTIVE

This study sought to investigate the attentional abilities of breast cancer patients after chemotherapy treatment using the attention network test (ANT).

METHODS

The participants included breast cancer patients who had undergone chemotherapy (CT, N = 58), patients who had not undergone chemotherapy (non-CT, N = 53), and matched healthy controls (HC, N = 55). All participants completed the ANT, which provides measures of three independent attention networks (alerting, orienting, and executive control) and neuropsychological background tests.

RESULTS

Our results indicated that the chemotherapy-treated breast cancer patients had significant deficits in the alerting and executive control networks but not in the orienting network. The CT group scored significantly lower in several cognitive tasks, including attention, memory, and information processing tasks, relative to the other two groups. Additionally, significant correlations were found between information processing and the efficiency of the executive control network within the CT group.

CONCLUSIONS

These results suggest that the three attention networks were selectively impaired following chemotherapy treatment, which affected different brain areas in the breast cancer survivors.

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.

Impairment of cognitive functioning during Sunitinib or Sorafenib treatment in cancer patients: a cross sectional study

Background

Impairment of cognitive functioning has been reported in several studies in patients treated with chemotherapy. So far, no studies have been published on the effects of the vascular endothelial growth factor receptor (VEGFR) inhibitors on cognitive functioning. We investigated the objective and subjective cognitive function of patients during treatment with VEGFR tyrosine kinase inhibitors (VEGFR TKI).

Methods

Three groups of participants, matched on age, sex and education, were enrolled; 1. metastatic renal cell cancer (mRCC) or GIST patients treated with sunitinib or sorafenib (VEGFR TKI patients n = 30); 2. patients with mRCC not receiving systemic treatment (patient controls n = 20); 3. healthy controls (n = 30). Sixteen neuropsychological tests examining the main cognitive domains (intelligence, memory, attention and concentration, executive functions and abstract reasoning) were administered by a neuropsychologist. Four questionnaires were used to assess subjective cognitive complaints, mood, fatigue and psychological wellbeing.

Results

No significant differences in mean age, sex distribution, education level or IQ were found between the three groups. Both patient groups performed significantly worse on the cognitive domains Learning & Memory and Executive Functions (Response Generation and Problem Solving) compared to healthy controls. However only the VEGFR TKI patients showed impairments on the Executive subdomain Response Generation. Effect sizes of cognitive dysfunction in patients using VEGFR TKI were larger on the domains Learning & Memory and Executive Functions, compared to patient controls. Both patients groups performed on the domain Attention & Concentration the same as the healthy controls. Longer duration of treatment on VEGFR TKI was associated with a worse score on Working Memory tasks.

Conclusions

Our data suggest that treatment with VEGFR TKI has a negative impact on cognitive functioning, specifically on Learning & Memory, and Executive Functioning. We propose that patients who are treated with VEGFR TKI are monitored and informed for possible signs or symptoms associated with cognitive impairment.

Trial registration

ClinicalTrials.gov Identifier: NCT01246843.

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

BACKGROUND

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

PATIENTS AND METHODS

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

RESULTS

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

CONCLUSIONS

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

The effects of cognitive behavioral therapy for postcancer fatigue on perceived cognitive disabilities and neuropsychological test performance

CONTEXT

After successful cancer treatment, a substantial number of survivors continue to experience fatigue and related concentration and memory problems. Severe fatigue after cancer treatment can be treated effectively with cognitive behavioral therapy (CBT), but it is unclear whether CBT has an effect on cognitive functioning.

OBJECTIVES

We hypothesized that patients would report less cognitive disability after treatment with CBT for cancer-related fatigue. CBT was not expected to affect neuropsychological test performance, as it has been shown that fatigue is not associated with test performance.

METHODS

Data were used from a randomized controlled trial in which 98 severely fatigued cancer survivors, treated at least one year previously, were assessed at baseline (T1) and six months post-baseline (T2). Patients were randomly assigned to receive CBT (n = 50) or to a waiting list (WL) control condition (n = 48). Self-reported cognitive disability was assessed by the Concentration subscale of the Checklist Individual Strength and the Alertness Behavior subscale of the Sickness Impact Profile. Neuropsychological test performance was measured by the symbol digit modalities task and two reaction time tasks.

RESULTS

Patients who received CBT for post-cancer fatigue reported significantly less cognitive disability compared with those in the WL group. CBT also was associated with a clinically relevant reduction in concentration problems (CBT, 32% vs. WL, 2%). There were no significant differences in neuropsychological test performance between the CBT and WL groups.

CONCLUSION

CBT for post-cancer fatigue has already been shown to be an effective therapy. The present study demonstrates that CBT also may lead to a decrease in perceived cognitive disability.

Cognitive effects of cancer and its treatments at the intersection of aging: what do we know; what do we need to know?

There is a fairly consistent, albeit non-universal body of research documenting cognitive declines after cancer and its treatments. While few of these studies have included subjects aged 65 years and older, it is logical to expect that older patients are at risk of cognitive decline. Here, we use breast cancer as an exemplar disease for inquiry into the intersection of aging and cognitive effects of cancer and its therapies. There are a striking number of common underlying potential biological risks and pathways for the development of cancer, cancer-related cognitive declines, and aging processes, including the development of a frail phenotype. Candidate shared pathways include changes in hormonal milieu, inflammation, oxidative stress, DNA damage and compromised DNA repair, genetic susceptibility, decreased brain blood flow or disruption of the blood-brain barrier, direct neurotoxicity, decreased telomere length, and cell senescence. There also are similar structure and functional changes seen in brain imaging studies of cancer patients and those seen with "normal" aging and Alzheimer's disease. Disentangling the role of these overlapping processes is difficult since they require aged animal models and large samples of older human subjects. From what we do know, frailty and its low cognitive reserve seem to be a clinically useful marker of risk for cognitive decline after cancer and its treatments. This and other results from this review suggest the value of geriatric assessments to identify older patients at the highest risk of cognitive decline. Further research is needed to understand the interactions between aging, genetic predisposition, lifestyle factors, and frailty phenotypes to best identify the subgroups of older patients at greatest risk for decline and to develop behavioral and pharmacological interventions targeting this group. We recommend that basic science and population trials be developed specifically for older hosts with intermediate endpoints of relevance to this group, including cognitive function and trajectories of frailty. Clinicians and their older patients can advance the field by active encouragement of and participation in research designed to improve the care and outcomes of the growing population of older cancer patients.

New approaches to understand cognitive changes associated with chemotherapy for non-central nervous system tumors

CONTEXT

Researchers have described a constellation of cognitive deficits (e.g., impairments in executive functions, working memory, attention, and information-processing speed) associated with cancer treatment, and specifically chemotherapy, for non-central nervous system tumors. However, findings have been inconsistent, largely because of measurement and study design issues.

OBJECTIVES

To propose ways for researchers to more clearly delineate and characterize the mild cognitive deficits and related outcomes that appear to affect a subset of cancer patients and suggest methods to make more effective use of the existing data to understand risk factors for impaired neuropsychological functioning.

METHODS

We examined the literature on the relationship between chemotherapy and cognitive impairment, as well as related literature on neuropsychological measurement, structural and functional neuroimaging, alternative measures of health outcomes, and integrative data analysis.

RESULTS

A more comprehensive picture of cognitive functioning might be obtained by incorporating nontraditional ecological measures, self-reports, computational modeling, new neuroimaging methods, and markers of occupational functioning. Case-control and integrative data analytic techniques potentially could leverage existing data to identify risk factors for cognitive dysfunction and test hypotheses about the etiology of these effects.

CONCLUSION

There is a need to apply new research approaches to understand the real-world functional implications of the cognitive side effects of chemotherapy to develop and implement strategies to minimize and remediate these effects before, during, and after cancer treatment.

Memory loss during lenalidomide treatment: a report on two cases

Background

There are many reports of cognitive dysfunction in patients receiving chemotherapy or targeted therapies. Many antineoplastic agents may be involved in the condition also known as “chemo brain” or “chemo fog”.

Case presentation

Two male patients (aged 41 and 70) with multiple myeloma developed severe, rapidly progressing cognitive impairment (mostly involving episodic memory) and loss of independence in activities of daily living during lenalidomide-based treatment. On withdrawal of the drug, one patient recovered normal cognitive function and independence in activities of daily living, whereas mild cognitive impairment persisted in the other patient. The Naranjo Adverse Drug Reaction Probability Scale score was 6 out of 13 for the first patient and 5 out of 13 for the second, suggesting a probable causal relationship between the adverse event and lenalidomide administration.

Conclusion

Lenalidomide may induce particular cognitive disorders (notably episodic memory impairments) in some patients. The drug’s putative neurotoxicity is probably promoted by specific risk factors (such as previous chemotherapy, prior mild cognitive impairment, age and the presence of cerebrovascular lesions).

Broadening the cancer and cognition landscape: the role of self-regulatory challenges

BACKGROUND

The potentially detrimental effects of cancer and related treatments on cognitive functioning have emerged as one of the key foci of cancer survivorship research, but little is known about how psychological variables other than depression influence these relationships. To illustrate the potential of social psychological perspectives, we examine how a self-regulatory analysis and specific self-regulatory challenges of contending with cancer-related expectancies and stereotypes provide conceptual frameworks for understanding some of the potential causes and consequences of cancer-related cognitive deficits.

METHODS

Literatures on cancer-related cognitive deficits, self-regulatory ego depletion, expectancy stereotypes, and their points of convergence are briefly reviewed.

RESULTS

A review and conceptual integration of relevant literatures suggest that coping with cancer can impair self-regulatory capacity. There is an overlap between cognitive deficits associated with self-regulatory challenge and with cancer and its treatment, and restoring self-regulatory resources can attenuate cancer-related cognitive deficits. Examination of specific regulatory challenges of contending with expectancies and stereotypes related to treatment suggests insights that can inform when and among whom cognitive deficits may most likely emerge.

CONCLUSIONS

Integrating social psychological ideas with a substantial knowledge base can illustrate novel research trajectories that can deepen our understanding of cancer-related cognitive deficits and their impact on psychosocial well-being.

Predictors of neuropsychological change in patients with chronic myelogenous leukemia and myelodysplastic syndrome

This study examined the course of neuropsychological functioning in patients with chronic myelogeous leukemia (n = 91) or myelodysplastic syndrome (n = 15) who underwent standard treatment for their disease or allogeneic hematopoietic stem cell transplantation (HSCT) at baseline, 12 months, and 18 months post-treatment. At baseline, 23% of the participants (n = 75) in the longitudinal sample had Z-scores on at least one of the neuropsychological tests that were <1.4. Participants in the study showed improvement over baseline at the 12 and 18 months assessments. The average Z-scores for the six cognitive domains in the longitudinal data set over the course of the study ranged from -0.89 to 0.59. Significant predictors of change in neuropsychological test scores included age, with older participants showing less improvement over time. Other predictors included baseline cognitive domains (language, memory, and attention), previous cocaine use, disease status, intelligence quotient, and quality of life measures. Findings support previous studies in patients with hematological malignancies who showed cognitive impairments at baseline prior to HSCT. However, there was little evidence for further cognitive decline over the course of 18 months.

Cognitive function in older women with breast cancer treated with standard chemotherapy and capecitabine on Cancer and Leukemia Group B 49907

Cognitive changes in older women receiving chemotherapy are poorly understood. We examined self-reported cognitive function for older women who received adjuvant chemotherapy on Cancer and Leukemia Group B (CALGB) 49907. CALGB 49907 randomized 633 women aged ≥65 with stage I-III breast cancer to standard adjuvant chemotherapy (cyclophosphamide-methotrexate-5-fluorouracil or doxorubicin-cyclophosphamide) versus capecitabine. We examined self-reported cognitive function in 297 women (CALGB 361002) who enrolled on the quality of life substudy and had no gross impairment on cognitive screening. Women were evaluated using an 18-item instrument at six time points (baseline through 24 months). At each time point for each patient, we calculated a cognitive function score (CFS) defined as the mean response of items 1-18 and defined impairment as a score >1.5 standard deviations above the overall average baseline score. Differences in scores by patient characteristics were evaluated using a Kruskal-Wallis test. A linear mixed-effects model was used to assess CFSs by treatment over time. Among 297 women, the median age was 71.5 (range 65-85) and 73 % had performance status of 0. Baseline depression and fatigue were reported in 6 and 14 % of patients, respectively. The average CFS at baseline was 2.08 (corresponding to "normal ability"), and baseline cognitive function did not differ by treatment regimen (p = 0.350). Over 24 months, women reported minimal changes at each time point and insignificant differences by treatment arm were observed. In a healthy group of older women, chemotherapy was not associated with longitudinal changes in self-reported cognitive function.

A pilot study of prospective memory functioning in early breast cancer survivors

AIMS

To evaluate prospective memory (PM) functioning in early breast cancer (BC) survivors and its association with fatigue and depression.

METHODS

The Memory for Intention Screening Test, the Center for Epidemiologic Studies Depression Scale and the Functional Assessment of Cancer Therapy-Fatigue subscale were administered to 80 patients and 80 aged-matched healthy controls.

RESULTS

Patients performed more poorly than controls on the memory test (p < 0.001) and had a higher rate of impairment (odds ratio = 5.5, p < 0.01). Fatigue mediated the relationship between Group membership and PM performance.

CONCLUSIONS

BC survivors exhibited a clear pattern of PM deficit and fatigue was a major contributor to this deficit. This suggests that a common mechanism may be involved in fatigue symptoms and memory disturbances experienced by patients. Further research is needed to evaluate the role of adjuvant therapy in PM deficits and to explore whether interventions targeted at improving fatigue may also improve memory functioning in BC survivors.

Preclinical evaluation of oncolytic δγ(1)34.5 herpes simplex virus expressing interleukin-12 for therapy of breast cancer brain metastases

The metastasis of breast cancer to the brain and central nervous system (CNS) is a problem of increasing importance. As improving treatments continue to extend patient survival, the incidence of CNS metastases from breast cancer is on the rise. New treatments are needed, as current treatments are limited by deleterious side effects and are generally palliative. We have previously described an oncolytic herpes simplex virus (HSV), designated M002, which lacks both copies of the γ₁34.5 neurovirulence gene and carries a murine interleukin 12 (IL-12) expression cassette, and have validated its antitumor efficacy in a variety of preclinical models of primary brain tumors. However, M002 has not been yet evaluated for use against metastatic brain tumors. Here, we demonstrate the following: both human breast cancer and murine mammary carcinoma cells support viral replication and IL-12 expression from M002; M002 replicates in and destroys breast cancer cells from a variety of histological subtypes, including “triple-negative” and HER2 overexpressing; M002 improves survival in an immunocompetent model more effectively than does a non-cytokine control virus. Thus, we conclude from this proof-of-principle study that a γ₁34.5-deleted IL-12 expressing oncolytic HSV may be a potential new therapy for breast cancer brain metastases.