Higher levels of fatigue are associated with higher CRP levels in disease-free breast cancer survivors

Role of Inflammation in Human Fatigue: Relevance of Multidimensional Assessments and Potential Neuronal Mechanisms

Fatigue is a highly disabling symptom in various medical conditions. While inflammation has been suggested as a potential contributor to the development of fatigue, underlying mechanisms remain poorly understood. In this review, we propose that a better assessment of central fatigue, taking into account its multidimensional features, could help elucidate the role and mechanisms of inflammation in fatigue development. A description of the features of central fatigue is provided, and the current evidence describing the association between inflammation and fatigue in various medical conditions is reviewed. Additionally, the effect of inflammation on specific neuronal processes that may be involved in distinct fatigue dimensions is described. We suggest that the multidimensional aspects of fatigue should be assessed in future studies of inflammation-induced fatigue and that this would benefit the development of effective therapeutic interventions.

Fatigue in people with localized colorectal cancer who do and do not receive chemotherapy: a longitudinal prospective study

BACKGROUND

Fatigue is associated with cancer and chemotherapy and may be sustained. Here, we describe a prospective longitudinal study evaluating fatigue and putative mechanisms in people with colorectal cancer (CRC).

PATIENTS AND METHODS

People with localized CRC completed the Functional Assessment of Cancer Treatment-Fatigue (FACT-F) questionnaire at baseline (before chemotherapy, if given), 6, 12, and 24 months. Healthy controls (HCs) were assessed at the first three time points. Fatigue was defined by standardized FACT-F scores ≤68/100. Quality-of-life (QoL, assessed by the FACT-G questionnaire), affective, and cognitive symptoms were evaluated. Associations were sought between fatigue, baseline factors, and blood tests (including hemoglobin, cytokines, and sex hormones). Regression analyses, Fisher's exact tests, and Wilcoxon rank-sum tests assessed levels of fatigue at each time point and change in fatigue from baseline. A repeated-measures analysis investigated prognostic factors of fatigue across all time points.

RESULTS

A total of 289 subjects with localized CRC (173 received chemotherapy) and 72 HCs were assessed. More CRC patients had fatigue than HCs at baseline (52% versus 26%, P < 0.001). Fatigue was increased in the chemotherapy (CTh) group at 6 months [CTh+ 70% versus CTh- 31% (P < 0.001), HCs 22%] and remained more common at 12 [CTh+ 44% versus CTh- 31% (P = 0.079)] and 24 months [CTh+ 39% versus CTh- 24% (P = 0.047)]. There was no significant difference between those not receiving chemotherapy and HCs at follow-up assessments. Fatigue was associated with poor QoL, affective and cognitive symptoms, but not consistently with cytokine levels. Predictors for sustained fatigue were baseline fatigue, treatment group, cognitive and affective symptoms, poorer QoL, and comorbidities.

CONCLUSIONS

CRC patients have more fatigue than HCs at baseline. Fatigue peaks immediately after adjuvant chemotherapy, but remains common for 2 years in those who receive chemotherapy. Cognitive and affective symptoms, QoL, comorbidities, chemotherapy, and baseline fatigue predict for longer term fatigue.

Fatigue is associated with inflammation in patients with head and neck cancer before and after intensity-modulated radiation therapy

Patients with head and neck cancer (HNC) receiving intensity-modulated radiation therapy (IMRT) have particularly high rates of fatigue, and pre- and post-radiotherapy fatigue are prognostic factors for pathologic tumor responses and poor survival. Although inflammation has been proposed as one of the potential mechanisms of fatigue in cancer patients, findings have not been consistent, and there is a dearth of longitudinal studies. Accordingly, we conducted a prospective study in 46 HNC patients pre- and one-month post-IMRT. Fatigue was measured by the Multidimensional Fatigue Inventory (MFI)-20 at both time points along with the assessment of peripheral blood inflammatory markers including interleukin (IL)-6, soluble tumor necrosis factor receptor 2, and C-reactive protein (CRP) and gene expression. Generalized estimating equations were used to examine the association between inflammatory markers and fatigue. Gene enrichment analysis using MetaCore software was performed using up-regulated genes that were significantly associated with IMRT and fatigue. Significant associations between fatigue and IL-6 as well as CRP, which were independent of time, were observed. In addition the change in fatigue from pre- to post-IMRT was positively associated with the change in IL-6 and CRP. Analysis of up-regulated gene transcripts as a function of IMRT and fatigue revealed overrepresentation of transcripts related to the defense response and nuclear factor kappa B. In conclusion, our findings support the hypotheses that inflammation is associated with fatigue over time in HNC patients. Future studies on how inflammation contributes to fatigue as well as strategies targeting inflammation to reduce fatigue are warranted.

Fatigue-induced Orosomucoid 1 Acts on C-C Chemokine Receptor Type 5 to Enhance Muscle Endurance

Understanding and managing fatigue is a significant challenge in clinic and society. In attempting to explore how the body responds to and regulates fatigue, we found in rodent fatigue models that orosomucoid 1 (ORM1) was significantly increased in multiple tissues, including blood and muscle. Interestingly, administration of exogenous ORM1 increased muscle glycogen and enhanced muscle endurance, whereas ORM1 deficiency resulted in a significant decrease of muscle endurance both in vivo and in vitro, which could largely be restored by exogenous ORM1. Further studies demonstrated that ORM1 can bind to C-C chemokine receptor type 5 (CCR5) on muscle cells and deletion of the receptor abolished the effect of ORM1. Thus, fatigue upregulates the level of ORM1, which in turn functions as an anti-fatigue protein to enhance muscle endurance via the CCR5 pathway. Modulation of the level of ORM1 and CCR5 signaling could be a novel strategy for the management of fatigue.

Fatigue and Quality of Life Outcomes of Palliative Care Consultation: A Prospective, Observational Study in a Tertiary Cancer Center

Purpose:

Fatigue is one of the most common symptoms seen in patients with advanced cancer. It is known to influence the Quality of Life (QoL) of patients. This study examines the interrelationship of fatigue and QoL in patients with advanced cancer on palliative care.

Methods:

A prospective cohort study was conducted in the outpatient clinic of the Department of Palliative Medicine from January to June 2014. Patients with advanced cancer registered with hospital palliative care unit, meeting the inclusion criteria (Eastern Cooperative Oncology Group [ECOG] ≤3, Edmonton Symptom Assessment Scale [ESAS] fatigue score ≥1), and willing to participate in the study were assessed for symptom burden (ESAS) and QoL (European Organization for Research and Treatment of Cancer QoL Core 15-Palliative module [EORTC-QoL PAL15]). All study patients received standard palliative care consultation and management. They were followed up in person or telephonically within 15–30 days from the first consult for assessment of outcomes.

Results:

Of a total of 500 cases assessed at baseline, 402 were available for follow-up (median age of 52 years; 51.6% male). On the EORTC-QoL PAL15 scale, overall QoL, emotional functioning, and constipation were found to be significantly associated with severity of fatigue at baseline (P < 0.05). Statistically significant improvement in fatigue score was observed (P < 0.001) at follow-up. Improvement in physical functioning and insomnia were significantly associated with better fatigue outcomes.

Conclusions:

Fatigue improved with the standard palliative care delivered at our specialty palliative care clinic. Certain clinical, biochemical factors and QoL aspects were associated with fatigue severity at baseline, improvement of which lead to lesser fatigue at follow-up.

Levels in neurotransmitter precursor amino acids correlate with mental health in patients with breast cancer

Breast cancer is the most common cancer among females. Approximately 30% of cancer patients develop depression or depressive adaptation disorder within 5 years post diagnosis. Low grade inflammation and subsequent changes in neurotransmitter levels could be the pathophysiological link. In the current study we investigated the association of neurotransmitter precursor amino acids with a diagnosis of depression or state anxiety in 154 subjects suffering from breast cancer (BCA(+)), depression (DPR(+)), both or neither. Sociodemographic parameters, severity of depressive symptoms, and state anxiety (ANX) were recorded. Neopterin, kynurenine/tryptophan and phenylalanine/tyrosine were analysed by HPLC or ELISA. Significantly higher serum neopterin values were found in DPR(+) patients (p = 0.034) and in ANX(+) subjects (p = 0.008), as a marker of Th1-related inflammation. The phenylalanine/tyrosine ratio (index of the catecholamine pathway) was associated with the factors "breast cancer" and "depression" and their interaction (all p < 0.001); it was highest in the DPR(+)BCA(+) group. The kynurenine/tryptophan ratio (index of the serotonin pathway) was significantly associated with the factors "breast cancer" and "state anxiety" and their interaction (p < 0.001, p = 0.026, p = 0.02, respectively); it was highest in the ANX(+)BCA(+) group. In BCA(+) patients kynurenine/tryptophan ratios correlated with severity of state anxiety (r = 0.226, p = 0.048, uncorrected) and phenylalanine/tyrosine ratios with severity of depressive symptoms (r = 0.376, p < 0.05, corrected). In conclusion, levels of neurotransmitter precursor amino acids correlate with mental health, an effect which was much more pronounced in BCA(+) patients than in BCA(-) subjects. Aside from identifying underlying pathophysiological mechanisms, these results could be the basis for future treatment studies: in BCA(+) patients with depression the use of serotonin-noradrenaline reuptake inhibitors might be recommended while in those with predominant anxiety selective serotonin reuptake inhibitors might be the treatment of choice.

The biology of cancer-related fatigue: a review of the literature

PURPOSE

Understanding the etiology of cancer-related fatigue (CRF) is critical to identify targets to develop therapies to reduce CRF burden. The goal of this systematic review was to expand on the initial work by the National Cancer Institute CRF Working Group to understand the state of the science related to the biology of CRF and, specifically, to evaluate studies that examined the relationships between biomarkers and CRF and to develop an etiologic model of CRF to guide researchers on pathways to explore or therapeutic targets to investigate.

METHODS

This review was completed by the Multinational Association of Supportive Care in Cancer Fatigue Study Group-Biomarker Working Group. The initial search used three terms (biomarkers, fatigue, cancer), which yielded 11,129 articles. After removing duplicates, 9145 articles remained. Titles were assessed for the keywords "cancer" and "fatigue" resulting in 3811 articles. Articles published before 2010 and those with samples <50 were excluded, leaving 75 articles for full-text review. Of the 75 articles, 28 were further excluded for not investigating the associations of biomarkers and CRF.

RESULTS

Of the 47 articles reviewed, 25 were cross-sectional and 22 were longitudinal studies. More than half (about 70 %) were published recently (2010-2013). Almost half (45 %) enrolled breast cancer participants. The majority of studies assessed fatigue using self-report questionnaires, and only two studies used clinical parameters to measure fatigue.

CONCLUSIONS

The findings from this review suggest that CRF is linked to immune/inflammatory, metabolic, neuroendocrine, and genetic biomarkers. We also identified gaps in knowledge and made recommendations for future research.

Is there any association of personality traits with vascular endothelial function or systemic inflammation?

Background:

Evidences showed association of some personality traits with increased risk of cardiovascular diseases, but mediated mechanisms are not entirely described. In this study, we investigated the association of different personality traits with systemic inflammation and endothelial function as probable mediators.

Methods:

This cross-sectional study was conducted in 2011 on 40-60 years old employees of an industrial company located in Isfahan city (central Iran). Participants were selected through simple random sampling. Personality types were evaluated using the neuroticism-extroversion-openness personality inventory and systemic inflammatory status was determined with high sensitive C-reactive protein (hs-CRP) level. To evaluate endothelial function flow mediated dilation (FMD) were measured. The obtained data were analyzed with univariate correlation and multiple linear regression tests.

Results:

A total of 254 cases with mean age of 51.4 ± 6.1 years were evaluated. There was no significant relationship between hs-CRP level and FMD with the personality traits in univariate analysis. In multivariate analysis, no association was found between the scores of personality traits and FMD with controlling the factors such as age, body mass index dyslipidemia, hypertension and diabetes. Only there was an inverse association between conscientiousness score and hs-CRP (β = −0.241, P = 0.013).

Conclusions:

In our population who were the employees of an industrial company, no relationship was found between specific personality trait and endothelial dysfunction. However, we found that the personality trait of responsibility (conscientiousness) is negatively associated with inflammation. Further multi-center studies and also cohort studies are recommended in this regard.

Elevated concentration of C-reactive protein is associated with pregnancy-related co-morbidities but not with relapse activity in multiple sclerosis

During pregnancy, alterations take place in mother's immune system with the goal of maintaining a successful pregnancy, and delivering healthy offspring. Immune alterations include activation of the innate immune system and dampening of cell-mediated adaptive immunity. Due to these alterations, cell-mediated autoimmune diseases typically ameliorate during pregnancy. The objectives of this study were to evaluate whether C-reactive protein (CRP) concentration, a sensitive marker of systemic inflammation (1) is increased during MS pregnancy (2) predicts pregnancy-related co-morbidities associated with MS (3) predicts MS disease activity after delivery. CRP concentration was measured using a high sensitivity assay from seven prospectively collected serum samples of 41 MS patients and 19 controls during pregnancy and 6 months after delivery. Annualized relapse rates, EDSS, fatigue scores and obstetric details of the patients were recorded. Delivery-related CRP levels were significantly elevated both among MS patients and in controls. CRP levels were higher during pregnancy than during the postpartum period in both study groups. Delivery-related elevated CRP levels did not correlate with postpartum disease activity. MS patients with eventual gestational diabetes had a significantly higher median CRP in the beginning of pregnancy compared to non-diabetic MS patients (9.28 vs. 2.98 mg/l, p = 0.0025). MS patients reporting fatigue had a significantly higher CRP throughout pregnancy compared to patients without fatigue. Higher CRP values were associated with pregnancy-related co-morbidities but not with MS disease activity.

Cancer-related fatigue--mechanisms, risk factors, and treatments

Fatigue is one of the most common adverse effects of cancer that might persist for years after treatment completion in otherwise healthy survivors. Cancer-related fatigue causes disruption in all aspects of quality of life and might be a risk factor of reduced survival. The prevalence and course of fatigue in patients with cancer have been well characterized and there is growing understanding of the underlying biological mechanisms. Inflammation seems to have a key role in fatigue before, during, and after cancer-treatment. However, there is a considerable variability in the presentation of cancer-related fatigue, much of which is not explained by disease-related or treatment-related characteristics, suggesting that host factors might be important in the development and persistence of this symptom. Indeed, longitudinal studies have identified genetic, biological, psychosocial, and behavioural risk factors associated with cancer-related fatigue. Although no current gold-standard treatment for fatigue is available, a variety of intervention approaches have shown beneficial effects in randomized controlled trials, including physical activity, psychosocial, mind-body, and pharmacological treatments. This Review describes the mechanisms, risk factors, and possible interventions for cancer-related fatigue, focusing on recent longitudinal studies and randomized trials that have targeted fatigued patients.

Yoga reduces inflammatory signaling in fatigued breast cancer survivors: a randomized controlled trial

BACKGROUND

Yoga is a popular mind-body therapy that has demonstrated beneficial effects on psychological, behavioral, and functional outcomes. However, few studies have investigated effects on inflammatory processes. This study tested the hypothesis that an Iyengar yoga intervention specifically designed for fatigued breast cancer survivors would lead to decreases in inflammation-related gene expression and circulating markers of proinflammatory cytokine activity.

METHODS

Breast cancer survivors with persistent cancer-related fatigue were randomized to a 12-week Iyengar yoga intervention (n=16) or a 12-week health education control condition (n=15). Blood samples were collected at baseline, post-intervention, and at a 3-month follow-up for genome-wide transcriptional profiling and bioinformatic analyses. Plasma inflammatory markers and salivary cortisol were also assessed.

RESULTS

In promoter-based bioinformatics analyses, the yoga group showed reduced activity of the pro-inflammatory transcription factor nuclear factor kappa B (NF-κB), increased activity of the anti-inflammatory glucocorticoid receptor, and reduced activity of cAMP response element-binding protein (CREB) family transcription factors relative to controls (all ps<.05). There was also a significant intervention effect on the soluble tumor necrosis factor receptor type II (sTNF-RII), a marker of TNF activity; plasma levels of sTNF-RII remained stable in the yoga group, whereas levels of this marker increased in the health education group (p=.028). A similar, non-significant trend was observed for the interleukin 1 receptor antagonist (p=.16). No significant changes in C reactive protein (CRP), interleukin 6 (IL-6), or diurnal cortisol measures were observed.

CONCLUSIONS

A 12-week restorative Iyengar yoga intervention reduced inflammation-related gene expression in breast cancer survivors with persistent fatigue. These findings suggest that a targeted yoga program may have beneficial effects on inflammatory activity in this patient population, with potential relevance for behavioral and physical health.

Weight, inflammation, cancer-related symptoms and health related quality of life among breast cancer survivors

Maintaining weight is important for better prognosis of breast cancer survivors. The associations between weight and cancer-related symptoms are not known. We examined associations among weight, weight change, inflammation, cancer-related symptoms, and health-related quality of life (HRQOL) in a cohort of stage 0-IIIA breast cancer survivors. Participants were recruited on average 6 months (2–12 months) after diagnosis. Height, weight, and C-reactive protein (CRP) were assessed at approximately 30 months post-diagnosis; cancer-related symptoms (chest wall and arm symptoms, vasomotor symptoms, urinary incontinence, vaginal symptoms, cognition/mood problems, sleep, sexual interest/function), and HRQOL (SF-36) were assessed at approximately 40 months post-diagnosis. Weight was measured at baseline in a subset. Data on 661 participants were evaluable for body mass index (BMI); 483 were evaluable for weight change. We assessed associations between BMI (<25.0, 25.0–29.9, ≥30.0 kg/m2), post-diagnosis weight change (lost ≥5 %, weight change <5 %, gained ≥5 %), and CRP (tertile) with cancer-related symptoms and HRQOL using analysis of covariance. Higher symptoms scores indicate more frequent or severe symptoms. Higher HRQOL scores indicate better HRQOL. Compared with those with BMI <25 kg/m2, women with BMI ≥30 kg/m2 had the following scores: increased for arm symptoms (+25.0 %), urinary incontinence (+40.0 %), tendency to nap (+18.9 %), and poorer physical functioning (−15.6 %, all p < 0.05). Obese women had lower scores in trouble falling asleep (−9.9 %; p < 0.05). Compared with weight change <5 %, participants with ≥5 % weight gain had lower scores in physical functioning (−7.2 %), role-physical (−15.5 %) and vitality (−11.2 %), and those with weight loss ≥5 % had lower chest wall (−33.0 %) and arm symptom scores (−35.5 %, all p < 0.05). Increasing CRP tertile was associated with worse scores for chest wall symptoms, urinary incontinence, physical functioning, role-physical, vitality and physical component summary scores (all P trend < 0.05). Future studies should examine whether interventions to maintain a healthy weight and reduce inflammation could alleviate cancer-related symptoms and improve HRQOL.

C-reactive protein predicts fatigue independently of depression in breast cancer patients prior to chemotherapy

Heightened inflammatory activity has been proposed as a mechanism for the development of cancer-related fatigue (CRF), a common and distressing condition that can negatively affect quality of life. Inflammation is also implicated in the pathogenesis of depression, and depression is a strong predictor of CRF. Thus, the role of the pro-inflammatory cytokine network in CRF may be mediated by depression or both conditions may share similar underlying physiological processes. The current study investigated associations between fatigue, depression and inflammatory cytokine (IFN-γ, IL-6, TNF-α) and CRP concentrations, as well as kynurenine pathway (KP) activation, in 61 breast cancer patients prior to chemotherapy. Changes in inflammatory markers and KP activation over time were also explored, and associations with changes in fatigue and depression were examined. Higher levels of CRP were significantly correlated with fatigue and depression before chemotherapy; nevertheless, CRP predicted fatigue independently of depression. Although greater kynurenine concentrations were associated with increased immune activation, there was no evidence that the KP played a role in fatigue or depression. Furthermore, no relationships emerged between either fatigue or depression and IFN-γ, IL-6, or TNF-α before chemotherapy. Nevertheless, kynurenine levels pre- and post-treatment significantly predicted changes in depression, suggesting that heightened KP activation may contribute to depressive symptoms in patients treated for cancer. In addition, IL-6 significantly covaried with fatigue. These preliminary findings provide some support for the idea that low-grade inflammation contributes to the development of CRF, independently of depression; however, there was no evidence that this is mediated by KP activity.

The identification of plasma proteins associated with cancer-related fatigue syndrome (CRFS) in disease-free breast cancer patients using proteomic analysis

CONTEXT

Cancer-related fatigue syndrome (CRFS) affects a significant minority of women successfully treated for breast cancer, with symptoms lasting up to several years after finishing therapy.

OBJECTIVES

This analysis was conducted to identify plasma proteins associated with CRFS in disease-free breast cancer patients.

METHODS

Women were divided into those meeting the CRFS criteria (cases) and a control group on the basis of a diagnostic interview. Plasma samples were collected from 45 cases and 45 controls. Proteomic analysis was conducted using surface-enhanced laser desorption/ionization, a mass spectrometry (MS) technique. This was followed by further sample processing using one-dimensional gels and trypsin digest for protein identification using liquid chromatography and database searching.

RESULTS

CRFS was associated with a statistically significant increase in the intensity of seven MS spectra. A subsequent search of proteins corresponding to the MS spectra identified four acute phase proteins associated with a nonspecific immune response (serum amyloid A, collectin, and subunits of immunoglobulin G and complement C1Q).

CONCLUSION

These novel results (using a technique not previously used in fatigue research) add further weight to the hypothesis that CRFS may be precipitated and prolonged by a nonspecific sustained inflammatory response. Importantly, this has been identified from a global analysis of plasma, which was conducted with no prior assumptions. Although these results need confirmation, we would suggest that future treatments for CRFS should consider focusing on the modulation of this presumed prolonged immune response.

Serum cytokines and chronic fatigue in adults surviving after childhood leukemia and lymphoma

INTRODUCTION

Fatigue is a common and distressing symptom in all phases of the cancer trajectory. Chronic fatigue (CF) is defined as fatigue with duration ⩾6months. The etiology of CF in cancer survivors is poorly understood, but a link to inflammatory activity has been suggested. In the present study we explored the relation between CF and the levels of 17 cytokines among a national representative sample of 232 adult survivors after childhood lymphoma and acute lymphoblastic leukemia (ALL).

METHODS

Chalder's fatigue questionnaire assessed CF. The sera of the survivors were analyzed for 27 cytokines, where of 17 were detectable.

RESULTS

Median age at survey and diagnosis was 29.7years (range 18.6-54.5years) and 9.6years (range 0.3-18.0years), respectively. Median follow-up time was 21.5years (range 7.1-40.0years). CF was not associated with increased levels of any of the 17 detectable cytokines when all three diagnostic groups were included in the analyses. In sub-analyses of the non-Hodgkin lymphoma survivors only, those with CF had significant higher levels of IL-9, FGF, PDGF and eotaxin compared to those without CF (p<0.05). Gender, age, diagnosis, obesity, or reduced heart function did not impact upon the results. Differences in cytokine levels between the diagnostic groups were observed irrespective of the presence/absence of CF.

CONCLUSION

This study could not confirm a relation between levels of cytokines and CF in adults who survived childhood lymphoma and ALL, except for among NHL survivors. Despite the broad spectrum of cytokines and relatively large sample, small aberrances may not have been traced.

The role of intratumoral and systemic IL-6 in breast cancer

Chronic low-grade inflammation plays an important role in the pathogenesis of several cancer forms including breast cancer. The pleiotropic cytokine IL-6 is a key player in systemic inflammation, regulating both the inflammatory response and tissue metabolism during acute stimulations. Here, we review the associations between IL-6 and breast cancer ranging from in vitro cell culture studies to clinical studies, covering the role of IL-6 in controlling breast cancer cell growth, regulation of cancer stem cell renewal, as well as breast cancer cell migration. Moreover, associations between circulating IL-6 and risk of breast cancer, prognosis for patients with prevalent disease, adverse effects and interventions to control systemic IL-6 levels in patients are discussed. In summary, direct application of IL-6 on breast cancer cells inhibits proliferation in estrogen receptor positive cells, while high circulating IL-6 levels are correlated with a poor prognosis in breast cancer patients. This discrepancy reflects distinct roles of IL-6, with elevated systemic levels being a biomarker for tumor burden, physical inactivity, and impaired metabolism, while local intratumoral IL-6 signaling is important for controlling breast cancer cell growth, metastasis, and self renewal of cancer stem cells.

Cytokine genetic variations and fatigue among patients with breast cancer

PURPOSE

Fatigue is a common adverse effect of cancer treatment and may persist for years after treatment completion. However, risk factors for post-treatment fatigue have not been determined. On the basis of studies suggesting an inflammatory basis for fatigue, this study tested the hypothesis that expression-regulating polymorphisms in proinflammatory cytokine genes would predict post-treatment fatigue in breast cancer survivors.

PATIENTS AND METHODS

Women diagnosed with early-stage breast cancer (n = 171) completed questionnaires to assess fatigue and other behavioral symptoms (ie, depressive symptoms, memory complaints, sleep disturbance) and provided blood for genotyping within 3 months after primary treatment. Genomic DNA was extracted from peripheral-blood leukocytes and assayed for single nucleotide polymorphisms (SNPs) in the promoter regions of three cytokine genes: ILB -511 C>T (rs16944), IL6 -174 G>C (rs1800795), and TNF -308 G>A (rs1800629). An additive genetic risk score was computed by summing the number of high-expression alleles (zero, one, or two) across all three polymorphisms.

RESULTS

The genetic risk index was significantly associated with fatigue; as the number of high-expression alleles increased, so did self-reported fatigue severity (P = .002). Analyses of individual SNPs showed that TNF -308 and IL6 -174 were independently associated with fatigue (P = .032). The genetic risk index was also associated with depressive symptoms (P = .007) and memory complaints (P = .016).

CONCLUSION

These findings further implicate inflammatory processes as contributors to cancer-related fatigue and suggest a new strategy for identifying and treating patients at risk for this symptom based on genetic variants in proinflammatory cytokine genes.

Inflammation and cancer-related fatigue: mechanisms, contributing factors, and treatment implications

Fatigue is one of the most common and distressing side effects of cancer and its treatment, and may persist for years after treatment completion in otherwise healthy survivors. Guided by basic research on neuro-immune interactions, a growing body of research has examined the hypothesis that cancer-related fatigue is driven by activation of the pro-inflammatory cytokine network. In this review, we examine the current state of the evidence linking inflammation and cancer-related fatigue, drawing from recent human research and from experimental animal models probing effects of cancer and cancer treatment on inflammation and fatigue. In addition, we consider two key questions that are currently driving research in this area: what are the neural mechanisms of fatigue, and what are the biological and psychological factors that influence the onset and/or persistence of inflammation and fatigue in cancer patients and survivors? Identification of the mechanisms driving cancer-related fatigue and associated risk factors will facilitate the development of targeted interventions for vulnerable patients.

Biomarkers for chronic fatigue

Fatigue that persists for 6 months or more is termed chronic fatigue. Chronic fatigue (CF) in combination with a minimum of 4 of 8 symptoms and the absence of diseases that could explain these symptoms, constitute the case definition for chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME). Inflammation, immune system activation, autonomic dysfunction, impaired functioning in the hypothalamic-pituitary-adrenal axis, and neuroendocrine dysregulation have all been suggested as root causes of fatigue. The identification of objective markers consistently associated with CFS/ME is an important goal in relation to diagnosis and treatment, as the current case definitions are based entirely on physical signs and symptoms. This review is focused on the recent literature related to biomarkers for fatigue associated with CFS/ME and, for comparison, those associated with other diseases. These markers are distributed across several of the body's core regulatory systems. A complex construct of symptoms emerges from alterations and/or dysfunctions in the nervous, endocrine and immune systems. We propose that new insight will depend on our ability to develop and deploy an integrative profiling of CFS/ME pathogenesis at the molecular level. Until such a molecular signature is obtained efforts to develop effective treatments will continue to be severely limited.

Fatigue symptoms relate to systemic inflammation in patients with type 2 diabetes

Fatigue is frequent in patients with diabetes and this symptom appears to be more prominent in type 2 rather than type 1 diabetic subjects. Chronic inflammation represents one characteristic of type 2 diabetes that may contribute to fatigue symptoms. This possibility was assessed in a sample of 20 type 2 diabetic patients relatively to a group of 20 type 1 diabetic subjects. Specific dimensions of fatigue, including general fatigue, physical fatigue, reduced activity, mental fatigue and reduced motivation, were assessed using the Multidimensional-Fatigue-Inventory (MFI). Biological assays comprised the measurement of serum inflammatory markers [high-sensitive C-reactive-protein (hsCRP), high-sensitive interleukin-6 (hsIL-6), high-sensitive tumor-necrosis-factor-α (hsTNF-α) and neopterin]. Clinical parameters including indexes of adiposity were collected. In comparison to type 1 diabetic subjects, patients with type 2 diabetes exhibited higher fatigue scores, notably in the dimensions of general fatigue, physical fatigue and reduced activity, together with greater levels of inflammatory markers that correlated with indexes of adiposity. Regression analyses controlling for diabetes duration, insulin treatment status, glycemic control and fasting status, indicated that levels of inflammatory markers, in particular hsIL-6, hsCRP and neopterin, were associated with MFI fatigue dimensions in type 2 diabetic patients. Mediation analyses revealed that adiposity did not significantly account for the relationship of inflammatory markers with fatigue scores albeit coefficient regressions decreased somewhat when this variable was controlled for in regression models. These findings indicate that systemic low-grade inflammation relates to fatigue symptoms in patients with type 2 diabetes and suggest the involvement of inflammatory processes in the pathophysiology of diabetes-related fatigue.

Factors associated with the severity and improvement of fatigue in patients with advanced cancer presenting to an outpatient palliative care clinic

Background

The aim of this study was to determine factors associated with the severity of cancer related fatigue (CRF) and predictors of improvement of CRF at the first follow-up visit in patients with advanced cancer referred to outpatient palliative care clinic (OPC).

Methods

We reviewed the records of consecutive patients with advanced cancer presenting to OPC. Edmonton Symptom Assessment System (ESAS) scores were obtained at the initial and subsequent visits between January 2003 and December 2008. All patients received interdisciplinary care led by palliative medicine specialists following an institutional protocol. Fatigue improvement was defined as a reduction of ≥2 points in ESAS score relative to the baseline. Descriptive statistics were used to summarize patient characterstics. Univariate analyses were performed and only significant variables were included in multivariate regression analysis to determine factors associated with severity and improvement in CRF.

Results

A total of 1778 evaluable patients were analyzed (median age, 59 years; 52% male). The median time between visits was 15 days. Median fatigue scores on the ESAS were 6 at baseline and 5 at follow-up. Severity of all ESAS items and low serum albumin were associated with fatigue at baseline (p < 0.0001). The improvement of fatigue was observed in 586 patients (33%). The hierarchical model showed that fatigue improved over time (b = −0.009; p = 0.0009). low appetite (odds ratio [OR] = 1.09 per point; p = 0.0113) and genitourinary cancer (OR = 1.74 per point; p = 0.0458) were significantly associated with improvement of fatigue.

Conclusions

CRF is strongly associated with physical and emotional symptoms. Genitourinary cancer and low appetite at baseline were associated with successful improvement of fatigue.

A systematic review of the association between immunogenomic markers and cancer-related fatigue

Fatigue, which is one of the most commonly reported symptoms in cancer, can negatively impact the functional status and the health-related quality of life of individuals. This paper systematically reviews 34 studies to determine patterns of associations between immunogenomic markers and levels of cancer-related fatigue (CRF). Findings from the longitudinal studies revealed that elevated fatigue symptoms especially of women with early stages of breast cancer were associated with high levels of neutrophil/monocyte, IL-1ra, and IL-6 during radiation therapy; high levels of CD4+, IL-1β, and IL-6 with stressing stimuli; high levels of IL-1β during chemotherapy; low NK cell levels after chemotherapy; and presence of homozygous IL-6 and TNF alleles. In the cross-sectional studies, associations between levels of fatigue and immune/inflammatory markers were not consistently found, especially when covariates such as BMI, ethnicity, menopausal status, and educational level were controlled in the statistical analyses. However, a number of genomic markers were observed to be elevated mostly in fatigued breast cancer survivors in the cross-sectional studies. Gaps in knowledge and recommendations for future research are discussed.

Inflammation and fatigue dimensions in advanced cancer patients and cancer survivors: an explorative study

BACKGROUND

Inflammation may underlie cancer-related fatigue; however, there are no studies that assess the relation between fatigue and cytokines in patients with advanced disease versus patients without disease activity. Furthermore, the relation between cytokines and the separate dimensions of fatigue is unknown. Here, association of plasma levels of inflammatory markers with physical fatigue and mental fatigue was explored in advanced cancer patients and cancer survivors.

METHODS

A total of 45 advanced cancer patients and 47 cancer survivors completed the subscales Physical Fatigue and Mental Fatigue of the Multidimensional Fatigue Inventory. Plasma concentrations of C-reactive protein (CRP), interleukin-1 receptor antagonist (IL-1-ra), interleukin-6 (IL-6), interleukin-8 (IL-8), and neopterin were measured. Nonparametric tests were used to assess differences in fatigue intensity and levels of inflammatory markers and to determine correlation coefficients between the fatigue dimensions and inflammatory markers.

RESULTS

Compared with cancer survivors, patients with advanced cancer had higher levels of physical fatigue (median 16 vs 9, P < .001) and mental fatigue (median 11 vs 6, P = .01). They also had higher levels of all cytokines (P < .01). In advanced cancer, CRP (r = 0.49, P = .001), IL-6 (r = 0.43, P = .003), IL-1-ra (r = 0.32, P = .03), and neopterin (r = 0.25, P = .10) were correlated with physical but not with mental fatigue. In cancer survivors, only IL-1-ra was related to both physical fatigue (r = 0.24, P = .10) and mental fatigue (r = 0.35, P = .02).

CONCLUSIONS

In advanced cancer, inflammation seems to be associated with physical fatigue, but not to mental fatigue. In cancer survivors, there was no convincing evidence that inflammation plays a major role in fatigue.