Neuropsychological evaluation of patients with inoperable non-small cell lung cancer treated with combination chemotherapy or radiotherapy

Comparative effect of Tai Chi and aerobic exercise on cognitive function in advanced lung cancer survivors with perceived cognitive impairment: a three-arm randomized controlled trial with mediation analysis

PURPOSE

Cancer-related cognitive impairment is prevalent in metastatic lung cancer survivors. This study aimed to compare the effectiveness of aerobic exercise and Tai Chi on perceived cognitive function and the mediating role of psychoneurological symptoms with perceived cognitive impairment.

METHODS

In a subgroup of a parent randomized clinical trial, participants who reported cognitive impairment underwent a 16-week aerobic exercise (n = 49), Tai Chi (n = 48), and control (n = 54) groups. Measures included perceived cognitive function and psychoneurological symptoms (sleep disturbance, fatigue, anxiety, and depression) assessed at baseline (T0), 16-week (T1), and 1 year (T2).

RESULTS

Participants in Tai Chi showed significant improvements compared to aerobic exercise and control groups in perceived cognitive function at T1 (AE: between-group difference, 6.52; P < 0.001; CG: 8.34; P < 0.001) and T2 (AE: between-group difference, 3.55; P = 0.05; CG: 5.94; P < 0.001). Sleep disturbance, fatigue, anxiety, and depression at month 12 explained 24%, 31%, 32%, and 24% of the effect of the intervention on cognitive function at month 12, respectively. Only anxiety at month 4 explained 23% of the intervention effect at month 12.

CONCLUSIONS

Tai Chi demonstrated beneficial effects on cognitive function in advanced lung cancer survivors with perceived cognitive impairment. Improvement in cognitive function was mediated by reducing sleep disturbance, fatigue, anxiety, and depression, highlighting the importance of addressing these symptoms in future interventions to improve cognitive function, with anxiety playing a significant role at an earlier stage.

IMPLICATIONS FOR CANCER SURVIVORS

Tai Chi is a potentially safe complementary therapeutic option for managing cognitive impairment in this vulnerable population.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT04119778; retrospectively registered on 8 October 2019.

Role of inflammation and oxidative stress in chemotherapy-induced neurotoxicity

Chemotherapeutic agents may adversely affect the nervous system, including the neural precursor cells as well as the white matter. Although the mechanisms are not completely understood, several hypotheses connecting inflammation and oxidative stress with neurotoxicity are now emerging. The proposed mechanisms differ depending on the class of drug. For example, toxicity due to cisplatin occurs due to activation of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), which alters hippocampal long-term potentiation. Free radical injury is also involved in the cisplatin-mediated neurotoxicity as dysregulation of nuclear factor erythroid 2-related factor 2 (Nrf2) has been seen which protects against the free radical injury by regulating glutathione S-transferases and hemeoxygenase-1 (HO-1). Thus, correcting the imbalance between NF-κB and Nrf2/HO-1 pathways may alleviate cisplatin-induced neurotoxicity. With newer agents like bortezomib, peripheral neuropathy occurs due to up-regulation of TNF-α and IL-6 in the sensory neurons. Superoxide dismutase dysregulation is also involved in bortezomib-induced neuropathy. This article reviews the available literature on inflammation and oxidative stress in neurotoxicity caused by various classes of chemotherapeutic agents. It covers the conventional medicines like platinum compounds, vinca alkaloids, and methotrexate, as well as the newer therapeutic agents like immunomodulators and immune checkpoint inhibitors. A better understanding of the pathophysiology will lead to further advancement in strategies for management of chemotherapy-induced neurotoxicity.

Neurocognitive functioning following lung cancer treatment: The PRO-Long Study

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Lung cancer patients often receive loco-regional radiotherapy and systemic treatment.

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This may negatively impact neurocognitive functioning (NCF) of certain patients.

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Patient-reported psychological problems are not correlated with objective NCF.

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Baseline objective NCF in lung cancer patients may be a predictor for overall survival.

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More research is needed on the impact of systemic treatment and/or radiotherapy on cognition.

This observational cohort study investigates neurocognitive functioning (NCF) and its associations with overall survival (OS), disease-free survival (DFS) and patient-reported psychological toxicities in locally-advanced and metastatic non-small cell lung (NSCLC) cancer patients receiving loco-regional radiotherapy and/or systemic therapy. Objective NCF data was collected with six psychometrically validated neurocognitive tests. Subjective NCF was assessed with the cognitive domain of the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire Core 30 items. Psychological toxicity data was collected with the patient-reported outcomes version of the common terminology criteria for adverse events. Meaningful clinical important differences were determined for changes in NCF. Univariate Cox proportional hazards models and generalized linear models were used to determine statistical significance (p < 0.01).

In total, 50 patients were recruited. At baseline, 13 (26%) patients had an impaired objective NCF. Over time, deterioration was seen in 11% (n = 3), 5% (n = 1) and 6% (n = 1) of patients at 2–3, 6 and 12 months post-treatment. The OS of patients with a normal NCF at baseline was longer than those with an impaired baseline NCF (29.5 vs 17.1 months). No statistical significance has been reached between NCF and OS (p = .353) nor NCF and DFS (p = .251). Objective NCF was not correlated with subjective NCF (p = .193), nor anxiety (p = .504), depression (p = .513), memory problems (p = .813) and concentration problems (p = .813).

Systemic treatment and loco-regional radiotherapy may have a temporarily negative impact on NCF in a small proportion of locally-advanced and metastatic NSCLC. Baseline NCF could be a predictor for OS.

Factors associated with cognitive impairment and cognitive concerns in patients with metastatic non-small cell lung cancer

Background

Knowledge regarding cognitive problems in metastatic non-small cell lung cancer (mNSCLC) is limited. Such problems may include both patient-reported cognitive concerns and demonstrable cognitive impairment. Greater understanding of these outcomes is needed to inform rehabilitation strategies for these difficulties. We aimed to identify the frequency of cognitive problems and associated factors in patients with mNSCLC.

Methods

In this cross-sectional study, adults with mNSCLC completed validated neuropsychological tests and self-report questionnaires measuring cognitive concerns, neurobehavioral concerns, depression, demoralization, illness intrusiveness, self-esteem, and physical symptoms. Cognitive impairment (performance based) was defined according to International Cancer and Cognition Task Force criteria. Clinically significant cognitive concerns were defined by a score ≥1.5 SD below the normative mean on the Functional Assessment of Cancer Therapy-Cognitive Function Perceived Cognitive Impairment (FACT-Cog PCI). Univariate and multivariate logistic regression analyses were performed to identify associated factors.

Results

Of 238 patients approached, 77 participated (median age: 62 years; range: 37-82). Brain metastases were present in 41 patients (53%), and 23 (29%) received cranial irradiation. Cognitive impairment and cognitive concerns were present in 31 (40%) and 20 patients (26%), respectively. Cognitive impairment and cognitive concerns co-occurred in 10 patients (13%), but their severity was unrelated. Cognitive impairment was associated with cranial irradiation (odds ratio [OR] = 2.89; P = .04), whereas cognitive concerns were associated with greater illness intrusiveness (OR = 1.04; P = .03) and lower self-esteem (OR = 0.86; P = .03).

Conclusions

Cognitive impairment and cognitive concerns are both common in patients with mNSCLC but are not necessarily related, and their risk factors differ. The association of illness intrusiveness and self-esteem with cognitive concerns can inform therapeutic interventions in this population.

Impact of Lung Cancer Treatment on Cognitive Functioning

The impact of oncologic treatment for (non)-small-cell lung cancer (NSCLC and SCLC, respectively) on cognition is relevant when deciding which treatment is the most preferable option, especially when curation is not possible. A systematic search of Medline and EMBASE for studies on the effect of treatment on cognition in patients with lung cancer was performed. A total of 39 longitudinal articles were included. Study populations were heterogeneous with regards to stage and treatment type. In the 7 studies concerning SCLC, the median age of patients was between 59 and 68 years. Eighty-six percent of these studies had a loss to follow-up > 10%. Six studies used objective tests to assess cognition. Objective measurements showed a negative effect on attention, memory, and fluency after treatment. Thirty-three studies concerning NSCLC were included. The mean age of patients was between 53 and 77 years. Seventy percent of these studies included patients with stage III and IV NSCLC. Over one-half of the studies had a high rate of loss to follow-up. Eighty-eight percent used objective scales to assess cognitive functioning. Subjective decline of cognitive functioning up to 11.1% was experienced, with recovery at 4 to 6 months. Objective measurement of attention showed improvement over the course of chemotherapy. In SCLC, there is a significant negative effect on attention, memory, and fluency. In NSCLC, the longer term impact of treatment on both subjective and objective cognitive functioning appears limited. Thus, there is no evidence directing treatment choice for NSCLC based on longer term cognitive deficits. Further research is needed to precisely assess the impact of lung cancer treatment on cognition.

Preliminary comparison of neuropsychological performance in patients with non-small-cell lung cancer treated with chemotherapy or targeted therapy

PURPOSE

This cross-sectional pilot study aimed to compare the effects of chemotherapy and targeted therapy on neuropsychological performance and psychiatric symptoms in patients with non-small-cell lung cancer (NSCLC).

PATIENTS AND METHODS

A total of 113 patients with NSCLC were recruited. According to their type of cancer treatment, the patients were classified into chemotherapy (n=40), targeted therapy (n=33), and untreated control (n=40) groups. All participants completed five objective tests measuring various domains of cognitive function, a subjective cognitive functioning scale (Functional Assessment of Cancer Therapy-Cognitive Function; FACT-cog), and the Hospital Anxiety and Depression Scale (HADS) either within 6 months after diagnosis (for the untreated group) or about 18 months after treatment.

RESULTS

Overall, there were no significant intergroup differences in the proportions of patients with abnormal cognitive performance and psychiatric disturbances. Among the untreated NSCLC patients, 35% had impaired performance in at least one cognitive domain, and a comparable finding (30%-35%) was made for the other two treatment groups. The proportion of patients with impaired psychomotor speed was the highest (10%-15%) across various cognitive domains. Moreover, a significant proportion of NSCLC patients (15%-20%) exhibited HADS-defined anxiety and depression disorder. Finally, significant correlations were found between FACT-cog total scores and the HADS Depression subscale across all three groups.

CONCLUSION

This study demonstrated that 1) a substantial proportion of NSCLC patients exhibited cognitive impairments (especially regarding psychomotor speed) and psychiatric disturbances; 2) no significant differences were observed among the three patient groups for any subjective or objective measure of cognitive deficit; and 3) perceived cognitive impairment was significantly associated with depression or anxiety. Prompt treatment of psychiatric disorders to minimize their impact is therefore recommended.

Performance monitoring in lung cancer patients pre- and post-chemotherapy using fine-grained electrophysiological measures

No previous event-related potentials (ERPs) study has explored the error-related negativity (ERN) - an ERP component indexing performance monitoring - associated to cancer and chemotherapy-induced cognitive impairment in a lung cancer population. The aim of this study was to examine differences in performance monitoring in a small-cell lung cancer group (SCLC, C +) 1-month following chemotherapy and two control groups: a non-small cell lung cancer patient group (NSCLC, C −) prior to chemotherapy and a healthy control group (HC).

Seventeen SCLC (C +) underwent a neuropsychological assessment and an ERP study using a flanker and a stop-signal paradigm. This group was compared to fifteen age-, gender- and education-matched NSCLC (C −) and eighteen HC.

Between 20 and 30% of patients in both lung cancer groups (C + and C −) met criteria for cognitive impairment. Concerning ERPs, lung cancer patients showed lower overall hit rate and a severe ERN amplitude reduction compared to HC.

Lung cancer patients exhibited an abnormal pattern of performance monitoring thus suggesting that chemotherapy and especially cancer itself, may contribute to cognitive deterioration. ERN appeared as an objective laboratory tool sensitive to cognitive dysfunction in cancer population.

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This is the first study to explore error-related negativity in lung cancer patients.

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Lung cancer patients showed a severe ERN amplitude reduction.

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ERN resulted a potential biomarker of cognitive impairment in lung cancer population.

Altered Brain Functional Connectivity in Small-Cell Lung Cancer Patients after Chemotherapy Treatment: A Resting-State fMRI Study

Previous studies in small-cell lung cancer (SCLC) patients have mainly focused on exploring neurocognitive deficits associated with prophylactic cranial irradiation (PCI). Little is known about functional brain alterations that might occur due to chemotherapy treatment in this population before PCI is administered. For this reason, we used resting-state functional Magnetic Resonance Imaging (fMRI) to examine potential functional connectivity disruptions in brain networks, including the Default Mode Network (DMN), the Sensorimotor Network, and the Task-Positive Network (TPN). Nineteen SCLC patients after platinum-based chemotherapy treatment and thirteen controls were recruited in the current study. ROI-to-ROI and Seed-to-Voxel analyses were carried out and revealed functional connectivity deficits in patients within all the networks investigated demonstrating the possible negative effect of chemotherapy in cognitive functions in SCLC populations.

Longitudinal Brain Changes Associated with Prophylactic Cranial Irradiation in Lung Cancer

INTRODUCTION

The toxic effects of prophylactic cranial irradiation (PCI) and platinum-based chemotherapy on cognition in the lung cancer population have not yet been well established. In the present study we examined the longitudinal neuropsychological and brain structural changes observed in patients with lung cancer who were undergoing these treatments.

METHODS

Twenty-two patients with small cell lung cancer (SCLC) who underwent platinum-based chemotherapy and PCI were compared with two control groups: an age- and education-matched group of healthy controls (n = 21) and a group of patients with non-SCLC (NSCLC, n = 13) who underwent platinum-based chemotherapy. All groups were evaluated using a neuropsychological battery and multimodal structural magnetic resonance imaging: T1-weighted and diffusion tensor imaging at baseline (before PCI for SCLC and chemotherapy for NSCLC) and at 3 months after treatment. T1 voxel-based morphometry and tract-based spatial statistics were used to analyze microstructural changes in gray matter (GM) and white matter (WM). The European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire-Core Questionnaire was also completed.

RESULTS

Patients with SCLC exhibited cognitive deterioration in verbal fluency over time. Structural magnetic resonance imaging showed decreases in GM at 3 months in the right subcortical regions, bilateral insular cortex, and superior temporal gyrus in patients with SCLC compared with both control groups. Additionally, patients with SCLC showed decreases in GM over time in the aforementioned regions plus in the right parahippocampal gyrus and hippocampus, together with changes in the WM microstructure of the entire corpus callosum. These changes had a limited impact on responses to the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire-Core Questionnaire, however. Patients with NSCLC showed no cognitive or brain structural differences after chemotherapy.

CONCLUSIONS

This longitudinal study documents moderate neuropsychological deficits together with notable brain-specific structural changes (in GM and WM) in patients with SCLC after chemotherapy and PCI, suggesting that chemotherapy and especially PCI are associated with the development of cognitive and structural brain toxic effects.

Cognitive and brain structural changes in a lung cancer population

INTRODUCTION

No study has examined structural brain changes specifically associated with chemotherapy in a lung cancer population. The aim of this cross-sectional study was to assess differences in brain structure between small-cell lung cancer patients (C+) following chemotherapy, non-small-cell lung cancer patients (C-) before chemotherapy and healthy controls (HC).

METHODS

Twenty-eight small-cell lung cancer patients underwent a neuropsychological assessment and a structural magnetic resonance imaging, including T1-weighted and diffusion tensor imaging to examine gray matter density and white matter (WM) integrity, respectively, 1 month following completion of platinum-based chemotherapy. This group was compared with 20 age and education-matched non-small-cell lung cancer patients before receiving chemotherapy and 20 HC.

RESULTS

Both C+ and C- groups exhibited cognitive impairment compared with the HC group. The C+ group performed significantly worse than HC in verbal fluency and visuospatial subtests; C- performed significantly worse than both C+ and HC in verbal memory. Voxel-based morphometry analysis revealed lower gray matter density in the insula and parahippocampal gyrus bilaterally, and left anterior cingulate cortex in C+ compared with HC. Diffusion tensor imaging indices showed focal decreased WM integrity in left cingulum and bilateral inferior longitudinal fasciculus in the C+ group and more widespread decreased integrity in the C- group compared with the HC group.

CONCLUSION

This study demonstrates that lung cancer patients exhibit cognitive impairment before and after chemotherapy. Before the treatment, C- showed verbal memory deficits as well as a widespread WM damage. Following treatment, the C+ group performed exhibited lower visuospatial and verbal fluency abilities, together with structural gray matter and WM differences in bilateral regions integrating the paralimbic system.

Inhibitors of histone deacetylases enhance neurotoxicity of DNA damage

The nonselective inhibitors of class I/II histone deacetylases (HDACs) including trichostatin A and the clinically used suberoylanilide hydroxamic acid (SAHA, vorinostat) are neuroprotective in several models of neuronal injury. Here, we report that in cultured cortical neurons from newborn rats and in the cerebral cortex of whole neonate rats, these HDAC inhibitors exacerbated cytotoxicity of the DNA double-strand break (DSB)-inducing anticancer drug etoposide by enhancing apoptosis. Similar neurotoxic interactions were also observed in neurons that were treated with other DNA damaging drugs including cisplatin and camptothecin. In addition, in rat neonates, SAHA increased cortical neuron apoptosis that was induced by a single injection of the NMDA receptor antagonist dizocilpine (MK801). In etoposide-treated neurons, the nonselective HDAC inhibition resulted in more DSBs. It also potentiated etoposide-induced accumulation and phosphorylation of the pro-apoptotic transcription factor p53. Moreover, nonselective HDAC inhibition exacerbated neuronal apoptosis that was induced by the overexpressed p53. Importantly, such effects cannot be fully explained by inhibition of HDAC1, which is known to play a role in DSB repair and regulation of p53. The specific HDAC1 inhibitor MS275 only moderately enhanced etoposide-induced neuronal death. Although in etoposide-treated neurons MS275 increased DSBs, it did not affect activation of p53. Our findings suggest that besides HDAC1, there are other class I/II HDACs that participate in neuronal DNA damage response attenuating neurotoxic consequences of genotoxic insults to the developing brain.

d-Methionine protects against cisplatin-induced neurotoxicity in cortical networks

Cisplatin is a platinum-based chemotherapeutic agent widely used for the treatment of various types of cancer. Patients undergoing cisplatin treatment often suffer from a condition known as "chemobrain", ototoxicity, peripheral neuropathy, weight loss, nausea, vomiting, nephrotoxicity, seizures, hearing loss and tinnitus. d-Methionine (d-Met), a sulfur-containing nucleophilic antioxidant, has been shown to prevent cisplatin-induced side effects in animals without antitumor interference. In this study, we have used an in vitro model of cortical networks (CNs), enriched in auditory cortex cells; to quantify cisplatin neurotoxicity and the protective effects of d-Met. Dissociated neurons from auditory cortices of mouse embryos were grown on microelectrode arrays with 64 transparent indium-tin oxide electrodes, which enabled continuous optical and electrophysiological monitoring of network neurons. Cisplatin at 0.10-0.25 mM induced up to a 200% increase in spontaneous spiking activity, while concentrations at or above 0.5mM caused irreversible loss of neuronal activity, accompanied by cell death. Pretreatment with d-Met, at a concentration of 1.0mM, prevented the cisplatin-induced excitation at 0.10-0.25 mM, caused sustained excitation without occurrence of cell death at 0.5mM, and delayed cell death at 0.75 mM cisplatin. l-Methionine, the optical isomer, showed lower potency and less efficacy than d-Met, was less protective against 0.1mM cisplatin, and proved ineffective at a concentration of 0.5mM cisplatin. Pre-exposure time of d-Met was associated with the protective effects at 0.1 and 0.5mM cisplatin, with longer pre-exposure times exhibiting better protection. This study quantifies as a function of concentration and time that d-Met protects central nervous system tissue from acute cisplatin toxicity.

Nucleolar disruption and apoptosis are distinct neuronal responses to etoposide-induced DNA damage

Although DNA damaging topoisomerase inhibitors induce apoptosis in developing neurons, their effects on adult neurons have not yet been characterized. We report a blockage of RNA-Polymerase-1-driven transcription and nucleolar stress in neocortical neurons of adult rats after intracarotid injection of the DNA-topoisomerase-2 inhibitor, etoposide. Intracerebroventricular injection of etoposide induced a similar response in neonatal rats. In contrast, etoposide triggered neuronal apoptosis in the neonates, but not the adults. Nucleolar disruption and apoptosis were also observed in etoposide-challenged cultured cortical neurons from newborn rats. In that system, activation of the DNA double strand break signaling kinase ataxia telangiectasia-mutated protein kinase, p53 and p53-dependent apoptosis required lower etoposide concentrations than did the p53-independent induction of nucleolar stress. These distinct responses may be coupled to different forms of etoposide-induced DNA damage. Indeed, double strand breaks by the over-expressed endonuclease I-Ppo1 were sufficient to induce p53-dependent apoptosis. Moreover, nucleolar transcription was insensitive to such damage implying single strand breaks and/or topoisomerase-2-DNA adducts as triggers of nucleolar stress. Because nucleolar stress is not age-restricted, it may underlie non-apoptotic neurotoxicity of chemotherapy- or neurodegeneration-associated DNA damage by reducing ribosomal biogenesis in adult brain. Conversely, nucleolar insensitivity to double strand breaks likely contributes to mature neuron tolerance of such lesions.

Fluoxetine reverses the memory impairment and reduction in proliferation and survival of hippocampal cells caused by methotrexate chemotherapy

RATIONALE

Adjuvant cancer chemotherapy can cause long-lasting, cognitive deficits. It is postulated that these impairments are due to these drugs targeting neural precursors within the adult hippocampus, the loss of which has been associated with memory impairment.

OBJECTIVES

The present study investigates the effects of the chemotherapy, methotrexate (MTX) on spatial working memory and the proliferation and survival of the neural precursors involved in hippocampal neurogenesis, and the possible neuroprotective properties of the antidepressant fluoxetine.

METHODS

Male Lister hooded rats were administered MTX (75 mg/kg, two i.v. doses a week apart) followed by leucovorin rescue (i.p. 18 h after MTX at 6 mg/kg and at 26, 42 and 50 h at 3 mg/kg) and/or fluoxetine (10 mg/kg/day in drinking water for 40 days). Memory was tested using the novel location recognition (NLR) test. Using markers, cell proliferation (Ki67) and survival (bromodeoxyuridine/BrdU), in the dentate gyrus were quantified.

RESULTS

MTX-treated rats showed a cognitive deficit in the NLR task compared with the vehicle and fluoxetine-treated groups. Cognitive ability was restored in the group receiving both MTX and fluoxetine. MTX reduced both the number of proliferating cells in the SGZ and their survival. This was prevented by the co-administration of fluoxetine, which alone increased cell numbers.

CONCLUSIONS

These results demonstrate that MTX induces an impairment in spatial working memory and has a negative long-term effect on hippocampal neurogenesis, which is counteracted by the co-administration of fluoxetine. If translatable to patients, this finding has the potential to prevent the chemotherapy-induced cognitive deficits experienced by many cancer survivors.

Memory function before and after whole brain radiotherapy in patients with and without brain metastases

PURPOSE

To prospectively compare the effect of prophylactic and therapeutic whole brain radiotherapy (WBRT) on memory function in patients with and without brain metastases.

METHODS AND MATERIALS

Adult patients with and without brain metastases (n = 44) were prospectively evaluated with serial cognitive testing, before RT (T0), after starting RT (T1), at the end of RT (T2), and 6-8 weeks (T3) after RT completion. Data were obtained from small-cell lung cancer patients treated with prophylactic cranial irradiation, patients with brain metastases treated with therapeutic cranial irradiation (TCI), and breast cancer patients treated with RT to the breast.

RESULTS

Before therapy, prophylactic cranial irradiation patients performed worse than TCI patients or than controls on most test scores. During and after WBRT, verbal memory function was influenced by pretreatment cognitive status (p < 0.001) and to a lesser extent by WBRT. Acute (T1) radiation effects on verbal memory function were only observed in TCI patients (p = 0.031). Subacute (T3) radiation effects on verbal memory function were observed in both TCI and prophylactic cranial irradiation patients (p = 0.006). These effects were more pronounced in patients with above-average performance at baseline. Visual memory and attention were not influenced by WBRT.

CONCLUSIONS

The results of our study have shown that WBRT causes cognitive dysfunction immediately after the beginning of RT in patients with brain metastases only. At 6-8 weeks after the end of WBRT, cognitive dysfunction was seen in patients with and without brain metastases. Because cognitive dysfunction after WBRT is restricted to verbal memory, patients should not avoid WBRT because of a fear of neurocognitive side effects.

Potential Mechanisms for Chemotherapy-Induced Impairments in Cognitive Function

PURPOSE/OBJECTIVES

To review the domains of cognitive function and their corresponding neuroanatomic structures as well as present current evidence for neurotoxicity associated with specific chemotherapeutic agents and potential mechanisms for chemotherapy-induced cognitive impairments.

DATA SOURCES

Published research articles, review articles, and textbooks.

DATA SYNTHESIS

Chemotherapy does not appear to cross the blood-brain barrier when given in standard doses; however, many chemotherapy drugs have the potential to cause cognitive impairments through more than one mechanism. In addition, patient factors may be protective or place individuals at higher risk for cognitive impairments.

CONCLUSIONS

Although evidence of chemotherapy-induced impairments in cognitive function exists, no clinical studies have attempted to elucidate the mechanisms for chemotherapy-induced impairments in cognitive function. In addition, further studies are needed to determine predictive factors, potential biomarkers, and relevant assessment parameters.

IMPLICATIONS FOR NURSING

The ability to identify high-risk patients has important implications for practice in regard to informed consent, patient education about the effects of treatment, and preventive strategies.

A metaanalysis of studies of the effects of cancer chemotherapy on various domains of cognitive function

BACKGROUND

Little is known about the effects of chemotherapy on cognitive function. The purposes of this metaanalysis were to estimate the effect sizes for the effect of chemotherapy on each domain of cognitive function and to differentiate effect sizes by each method of comparison of effects (i.e., normative data, control group, or baseline data).

METHODS

Sixteen studies that evaluated cognitive function in chemotherapy patients were included in the study. DSTAT metaanalysis software was used to calculate an effect size and confidence intervals for each neuropsychologic test. Tests were assigned to a specific cognitive domain, and an average effect size was determined for each domain.

RESULTS

Only one domain of cognitive function (i.e., visual memory) had significant chemotherapy-induced impairment across all comparison types. However, when the neuropsychologic test scores of chemotherapy patients were compared with normative data, significant effect sizes were found for four domains of cognitive function (i.e., executive function, information processing speed, verbal memory, visual memory). In addition, significant, albeit small, effect sizes were found for language and verbal memory when chemotherapy patients' test scores were compared with test scores of healthy matched controls. All significant averaged effect sizes were in the negative direction, indicating that mean scores on neuropsychologic tests for patients who had received chemotherapy were on average lower than comparison scores.

CONCLUSION

Data from this metaanalysis supported the hypothesis that chemotherapy can have a negative impact on cognitive function. However, most deficits in this study ranged from small to moderate and were nonsignificant.

Cancer as a risk factor for long-term cognitive deficits and dementia

Previous studies have shown that cancer survivors frequently experience short-term cognitive deficits, but it is unknown how long these deficits last or whether they worsen over time. Using a co-twin control design, the cognitive function of 702 cancer survivors aged 65 years and older was compared with that of their cancer-free twins. Dementia rates were also compared in 486 of the twin pairs discordant for cancer. Cancer survivors overall, as well as individuals who had survived cancer for 5 or more years before cognitive testing, were more likely than their co-twins to have cognitive dysfunction (odds ratio [OR] = 2.10, 95% confidence interval [CI] = 1.36 to 3.24; P<.001; and OR = 2.71, 95% CI = 1.47 to 5.01; P<.001, respectively). Cancer survivors were also twice as likely to be diagnosed with dementia as their co-twins, but this odds ratio did not reach statistical significance (OR = 2.0, 95% CI = 0.86 to 4.67; P = .10). These results suggest that cancer patients are at increased risk for long-term cognitive dysfunction compared with individuals who have never had cancer, even after controlling for the influence of genetic factors and rearing environment.

What is the effect of systemic anticancer treatment on cognitive function?

Treatment regimens for solid tumours have been extensively investigated for their physical toxic effects, but far less is known about the potential impairment of cognitive function by anticancer treatment regimens. Here, we review published studies that examined cognitive function in adult patients receiving systemic therapy for solid tumours. Our review suggests that patients can experience cognitive changes related to their treatment. However, several studies had methodological limitations, such as use of a limited sample size, lack of baseline assessment, and lack of control for potential confounding factors. Better designed clinical trials are required so that the difficulties patients face in terms of reduced cognitive function as a result of anticancer treatment can be fully elucidated. These trials should have sufficient statistical power and, importantly, should also be prospective.

Neuropsychological effects of treatments for adults with cancer: a meta-analysis and review of the literature

A meta-analysis was conducted to evaluate possible neuropsychological effects of treatments for cancer in adults. A search revealed 30 studies, encompassing 29 eligible samples, and leading to inclusion of a total of 838 patients and control participants. A total of 173 effect sizes (Cohen's d) were extracted across 7 cognitive domains and as assessed in the literature via 3 methods of comparison (post-treatment compared with normative data, controls, or baseline performance). Statistically significant negative effect sizes were found consistently across both normative and control methods of comparison for executive function, verbal memory, and motor function. The largest effects were for executive function and verbal memory normative comparisons (-.93 and -.91, respectively). When limiting the sample of studies in the analyses to only those with relatively "less severe" diagnoses and treatments, the effects remained. While these results point toward some specific cognitive effects of systemic cancer therapies in general, no clear clinical implications can yet be drawn from these results. More research is needed to clarify which treatments may produce cognitive decrements, the size of those effects, and their duration, while ruling out a wide variety of possible mediating or moderating variables.

Low neuropsychologic performance among adult cancer survivors treated with chemotherapy

Decline in neuropsychologic test performance following adjuvant chemotherapy for various types of cancer has gained much research attention over the past decade. From available data, about one fourth to one third of individuals undergoing systemic chemotherapy exhibit measurable decrements in performance of standard tests of cognitive function. Many cancer survivors report that cognitive problems interfere with function and compromise quality of life. However, these declines appear subtle and there are little available longitudinal data examining pre- to post-treatment cognitive change. Further, there is little available evidence identifying the causes of cognitive decline. This paper reviews current literature on low neuropsychologic performance following systemic chemotherapy and hypotheses on the causes of cognitive symptoms following chemotherapy. Future research directions, with emphasis on longitudinal research design as well as treatment implications, are discussed.

Relations between fatigue, neuropsychological functioning, and physical activity after treatment for breast carcinoma: daily self-report and objective behavior

BACKGROUND

Previous research indicates that disease free breast carcinoma survivors who experienced severe fatigue also had many problems with regard to neuropsychological functioning and physical activity, measured with general self-report questionnaires. Both neuropsychological functioning and physical activity can be measured with daily self-report measures in addition to measures of objective behavior. The main objective of this study was to examine the relations between 1) fatigue and 2) daily self-reported and objective measures of neuropsychological functioning and physical activity.

METHODS

Disease free breast carcinoma survivors and age-matched women with no history of breast carcinoma filled out a daily self-observation list and wore an actometer during a period of 12 days. Furthermore, they performed two standardized tests to assess neuropsychological functioning.

RESULTS

No differences were found between severely fatigued disease free breast carcinoma survivors, nonseverely fatigued disease free breast carcinoma survivors, and women in a control group with regard to daily self-reported and objective physical activity. The severely fatigued disease free patients reported more impairment in neuropsychological functioning on daily questionnaires compared with nonseverely fatigued disease free patients and women in the control group. However, no differences were found between these three groups on a standardized concentration task. On a standardized reaction time task, no significant differences were found between the two groups of disease free breast carcinoma survivors: However, women in the severely fatigued group had a significantly longer reaction time compared with women in the control group.

CONCLUSIONS

Fatigue is correlated strongly with daily self-reported neuropsychological functioning, but not with objective neuropsychological functioning, in a laboratory setting. In the current study, fatigue was not correlated with daily self-reported and objective physical activity.

Cognitive effects of standard-dose chemotherapy in patients with cancer

Adult cancer survivors have reported experiencing persistent changes in cognitive function following treatment with chemotherapy. Increasing evidence supports the hypothesis that standard-dose chemotherapy can produce cognitive deficits in a subgroup of adult cancer survivors. Although these cognitive changes tend to be subtle deficits in memory, concentration, and the ability to remain focused or organized, these alterations in cognitive ability can have a significant impact on patients' quality of life generally, and on meeting career and educational goals specifically. This manuscript reviews the literature relevant to the cognitive impact of standard-dose chemotherapy in adults, outlines methodological issues related to the study of cognitive functioning in people with cancer, and discusses future directions for research in this area.

Cognitive function in breast cancer patients receiving adjuvant chemotherapy

PURPOSE

Breast cancer patients receiving chemotherapy have complained of difficulties in their ability to remember, think, and concentrate. This study assessed whether there are differences in cognitive function between breast cancer patients treated with standard-dose adjuvant chemotherapy compared with healthy controls.

PATIENTS AND METHODS

The High Sensitivity Cognitive Screen and the Profile of Mood States (POMS) were used to assess cognitive function and mood in a group of 107 women. The women consisted of 31 breast cancer patients receiving adjuvant chemotherapy (group A), 40 breast cancer patients who had completed adjuvant chemotherapy a median of 2 years earlier (group B), and 36 healthy controls (group C).

RESULTS

Univariate analysis showed statistically significant differences (P =.009) in overall cognitive function scores between groups A and C, with poorer function in patients receiving adjuvant chemotherapy. These differences remained significant (P =.046) when controlling for age, education level, and menopausal status. More patients had moderate or severe cognitive impairment in groups A and B than in controls (P </=.002). There were no significant differences in POMS scores between the groups, suggesting that the differences seen in cognitive scores were unlikely to be because of mood disturbance.

CONCLUSION

Cognitive differences were observed in breast cancer patients receiving adjuvant chemotherapy compared with healthy controls. These differences did not seem to be caused by significant differences in mood disturbance between the two groups. If confirmed, these results have substantial implications for informed consent, counseling, and psychosocial support of patients receiving adjuvant chemotherapy for breast cancer.

Cisplatin-based therapy: a neurological and neuropsychological review

The present paper reviews research in the area of the broad-spectrum chemotherapeutic agent cisplatin (cis-diamminedichloro-platinum II) and examines the implications for clinical neuropsychology arising from the neurological disruption associated with cisplatin-based therapy. The paper begins with a brief review of cisplatin treatment in terms other than survival alone, and examines the side-effects and the potential central nervous system (CNS) dysfunction in terms of neurological symptoms and concomitant implications for neuropsychology. Two main implications for clinical neuropsychology arising from cisplatin therapy are identified. First, cisplatin therapy impacts upon the psychological well-being of the patient, particularly during and in the months following treatment. It is suggested that during this time, a primary role for neuropsychology is to focus upon the monitoring and the active enhancement of the patient's social, psychological and spiritual resources. Second, with regard to neurocognitive changes, the review suggests that (1) neurocognitive assessment may not yield stable results within 8 months following treatment and (2) while perceptual, memory, attentional and executive dysfunction may be predicted following cisplatin treatment, little systematic research has been carried out to investigate such a possibility. Future research might profitably address this issue and also specifically examine the effects of low dosage cisplatin-based therapy and the effects of recently developed neuroprotective agents. Finally, there is some evidence to suggest that women may be more susceptible to neurotoxicity during cisplatin therapy, but no gender-related cognitive effects are reported in the cisplatin literature. Future research could usefully investigate gender differences in association with cisplatin chemotherapy.

Dimensions of symptom distress in women with advanced lung cancer: a factor analysis

OBJECTIVE

To explore the structure of symptom distress in women with advanced lung cancer.

DESIGN

Descriptive.

SETTING

Oncology clinics and private offices.

SUBJECTS

Sixty women with advanced lung cancer (71% non-small-cell); the majority received palliative treatment (88%).

OUTCOME MEASURES

Symptom Distress Scale and Karnofsky Performance Status Scale.

METHOD

Factor analytic techniques (principal components, varimax rotation) to investigate combinations of all symptoms in the Symptom Distress Scale and combinations of serious symptoms.

RESULTS

Fatigue, disruptions in outlook, frequent pain, and difficulties in sleeping were rated the most distressing and were the most prevalent serious disruptions. A four-factor solution for the symptom distress ratings explained 63.3% of the variance and revealed groups of items representing emotional and physical suffering, gastrointestinal distress, respiratory distress, and malaise. Symptoms with a rating of serious distress were represented by five factors with emotional and physical suffering as separate factors. Symptoms were significantly related to Karnofsky Performance Status.

CONCLUSIONS

Multiple symptoms formed distinct congregations of distress. Symptom control requires consideration as a multivariate approach.