The definitions, assessment, and dimensions of cancer-related fatigue: A scoping review.

PURPOSE: Cancer-related fatigue (CRF) is challenging to diagnose and manage due to a lack of consensus on its definition and assessment. The objective of this scoping review is to summarize how CRF has been defined and assessed in adult patients with cancer worldwide. METHODS: Four databases (PubMed, Embase, CINAHL Plus, PsycNet) were searched to identify eligible original research articles published in English over a 10-year span (2010-2020); CRF was required to be a primary outcome and described as a dimensional construct. Each review phase was piloted: title and abstract screening, full-text screening, and data extraction. Then, two independent reviewers participated in each review phase, and discrepancies were resolved by a third party. RESULTS: 2923 articles were screened, and 150 were included. Only 68% of articles provided a definition for CRF, of which 90% described CRF as a multidimensional construct, and 41% were identical to the National Comprehensive Cancer Network definition. Studies were primarily conducted in the United States (19%) and the majority employed longitudinal (67%), quantitative (93%), and observational (57%) study designs with sample sizes ≥ 100 people (57%). Participant age and race were often not reported (31% and 82%, respectively). The most common cancer diagnosis and treatment were breast cancer (79%) and chemotherapy (80%; n = 86), respectively. CRF measures were predominantly multidimensional (97%, n = 139), with the Multidimensional Fatigue Inventory (MFI-20) (26%) as the most common CRF measure and "Physical" (76%) as the most common CRF dimension. CONCLUSION: This review confirms the need for a universally agreed-upon definition and standardized assessment battery for CRF.

Mechanistic insights into behavioral clusters associated with cancer-related systemic inflammatory response.

PURPOSE OF REVIEW: This focused, narrative review mostly describes our team's investigations into the potential inflammatory mechanisms that contribute to the development of cancer-related gastrointestinal (GI) mucositis and its associated symptoms. This review summarizes details of our clinical and preclinical findings to test the role of inflammation in the development and occurrence of these cancer-related conditions. RECENT FINDINGS: GI mucositis (GIM) is a common, distressing condition reported by cancer patients. GIM is often clustered with other behaviors including fatigue, pain, anorexia, depression, and diarrhea. It is hypothesized that there is a common biologic mechanism underpinning this symptom cluster. Our multi-platform investigations revealed that GIM and its associated cluster of behaviors may be triggered by local inflammation spreading systemically causing pro-inflammatory-mediated toxicities, leading to alterations in immune, metabolic, and nervous system functions and activities. For example, behavioral toxicities related to local irradiation for non-metastatic cancer may be triggered by mGluR5 activation influencing prolonged T cell as well as NF-κB transcription factor activities. Thus, interventions targeting inflammation and associated pathways may be a reasonable strategy to alleviate GIM and its symptom cluster. SUMMARY: GIM may be a sign of a broader systemic inflammatory response triggered by cancer or its treatment. Addressing GIM and its associated symptoms primarily involves supportive care strategies focused on relieving symptoms, promoting healing, and preventing complications.

Self-reporting of psychoneurophysical (PNP) symptoms in adults with four chronic diseases: a protocol for a scoping review.

BACKGROUND: Patient self-reporting of health-specific information, including symptoms, allows healthcare providers to provide more timely, personalized, and patient-centered care to meet their needs. It is critical to acknowledge that symptom reporting draws from the individual's unique sociocultural background influencing how one perceives health and illness. This scoping review will explore whether racial groups with 4 chronic diseases (cardiovascular diseases, respiratory diseases, cancers, and diabetes) differ in self-reporting of psychoneurophysical (PNP) symptoms. The PNP symptoms of interest include depressive symptoms, fatigue, anxiety, pain, cognitive impairment, sleep impairment, mood impairment, irritability, and shortness of breath. METHODS: Four databases will be searched by a biomedical librarian: CINAHL Plus (EBSCOhost), Embase (Elsevier), PubMed (NLM), Web of Science: Core Collection (Clarivate Analytics), and limited to publications written in the English language. Two independent reviewers will screen the records' title, abstract, and then full text and extract the data from included articles using Covidence. A third reviewer will be used for resolving disagreements. Included articles must comprise adult patients with at least one of the specified chronic diseases who self-report at least one of the specified PNP symptoms. Studies that used clinician-administered questionnaires or obtained symptom responses from primary caregiver or patient designee will be excluded. Articles on patient-reported functionality or perceived quality of life will also be excluded from the review. Two reviewers will independently extract data (e.g., demographics, study design, racial group, chronic disease, measure/scale used for self-report) from each included article using Covidence and Microsoft Excel for data cleaning and analyses. DISCUSSION: This scoping review may potentially identify the relevant and practical implications related to clinical decision-making and health outcomes for patients experiencing the psychoneurophysical symptoms included in this study. The authors will present how the results can be utilized in clinical practice, health policy, and research planning. SYSTEMATIC REVIEW REGISTRATION: The protocol was registered on Open Science Framework (OSF) at: https://osf.io/ps7aw.

Comparing symptom clusters in cancer survivors by cancer diagnosis: A latent class profile analysis.

PURPOSE: Research on symptom clusters in oncology is progressing, but knowledge gaps remain. One question is whether the number and types of symptom subgroups (i.e., latent classes) differ based on cancer diagnosis. The purpose of this study was to: (1) identify and compare latent class subgroups based on four highly prevalent symptoms (pain, fatigue, sleep disturbance, and depression), and (2) examine the differences in sociodemographic and clinical factors in the identified latent classes across the seven cancer types (i.e., prostate, non-small cell lung, non-Hodgkin's lymphoma, breast, uterine, cervical, and colorectal cancer). METHODS: This study is a cross-sectional secondary analysis of data obtained from the My-Health study in partnership with four Surveillance, Epidemiology, and End Results (SEER) cancer registries located in California (two), Louisiana, and New Jersey. The sample included 4,762 cancer survivors 6-13 months following diagnosis of one of the seven cancer types mentioned. Latent class profile analysis was used. RESULTS: Subjects were primarily young (59% age 21-64 years), Caucasian (41%), married/cohabitating (58%) and unemployed (55%). The number and types of symptom subgroups varied across these seven cancer populations: four-subgroups were the common in prostate, lung, non-Hodgkin's lymphoma, and breast cancer survivors. Unmarried, low education, and unemployment status were associated with high risk of symptom burden across the cancer types. CONCLUSION: Identifying symptom subgroups by cancer diagnosis has the potential to develop innovative and effective targeted interventions in cancer survivors. Further research is needed to establish extensive knowledge in symptom clustering between treatment regimens, and short-term and long-term cancer survivors.

Associations of brain-derived neurotrophic factor rs6265 polymorphism and cognitive function in breast cancer survivors from a cross-sectional study.

BACKGROUND: Breast cancer survivors (BCS) often complain of cancer-related cognitive impairment (CRCI) during and even months after completing primary cancer treatments, particularly chemotherapy. The etiology of CRCI is unknown, but associations of CRCI with germline genetic polymorphisms have been reported, including Brain-Derived Neurotrophic Factor (BDNF) rs6265 polymorphism. The current study investigated the associations of specific BDNF rs6265 with CRCI. METHODS: Cancer-related cognitive impairment was assessed using subjective reports of cognitive symptoms (the version 1.0, 8-item short-forms of the Patient-Reported Outcomes Measurement Information System®) and computerized objective cognitive function scores (CANTAB®). BDNF rs6265 genotypes were determined from buccal swabs. The associations of specific BDNF rs6265 with CRCI were examined by either one-way analysis of variance or the Kruskal-Wallis test followed by post hoc tests and rank-based regression analysis. RESULTS: We examined 356 female BCS. The mean (SD) age was 55.6 (9.8) years old, the median (IQR) years since cancer diagnosis were 4.0 (6.0), and 331 (92.7%) were self-described as White. BCS carrying the Met/Met genotype showed poorer results on 'visual episodic memory and new learning' and 'spatial working memory and executive function.' This relationship was observed regardless of prior chemotherapy. CONCLUSION: Our findings suggest that carrying the BDNF rs6265 Met/Met genotype increases the risk for CRCI in BCS. These results are foundational in nature and provide important information to identify mechanisms underpinning CRCI.

Exploring the links of skeletal muscle mitochondrial oxidative capacity, physical functionality, and mental well-being of cancer survivors.

Physical impairments following cancer treatment have been linked with the toxic effects of these treatments on muscle mass and strength, through their deleterious effects on skeletal muscle mitochondrial oxidative capacity. Accordingly, we designed the present study to explore relationships of skeletal muscle mitochondrial oxidative capacity with physical performance and perceived cancer-related psychosocial experiences of cancer survivors. We assessed skeletal muscle mitochondrial oxidative capacity using in vivo phosphorus-31 magnetic resonance spectroscopy (31P MRS), measuring the postexercise phosphocreatine resynthesis time constant, τPCr, in 11 post-chemotherapy participants aged 34-70 years. During the MRS procedure, participants performed rapid ballistic knee extension exercise to deplete phosphocreatine (PCr); hence, measuring the primary study outcome, which was the recovery rate of PCr (τPCr). Patient-reported outcomes of psychosocial symptoms and well-being were assessed using the Patient-Reported Outcomes Measurement Information System and the 36-Item Short Form health survey (SF-36). Rapid bioenergetic recovery, reflected through a smaller value of τPCr was associated with worse depression (rho ρ = - 0.69, p = 0.018, and Cohen's d = - 1.104), anxiety (ρ = - 0.61, p = .046, d = - 0.677), and overall mental health (ρ = 0.74, p = 0.010, d = 2.198) scores, but better resilience (ρ = 0.65, p = 0.029), and coping-self efficacy (ρ = 0.63, p = 0.04) scores. This is the first study to link skeletal muscle mitochondrial oxidative capacity with subjective reports of cancer-related behavioral toxicities. Further investigations are warranted to confirm these findings probing into the role of disease status and personal attributes in these preliminary results.

Relationship of cancer-related fatigue with psychoneurophysiological (PNP) symptoms in breast cancer survivors.

PURPOSE: Cancer-related fatigue (CRF) is a highly prevalent and debilitating symptom reported by breast cancer survivors (BCS). CRF has been associated with the co-occurrence of anxiety, depression, poor sleep quality, cognitive impairment, which are collectively termed as psychoneurophysiological (PNP) symptoms. CRF and these PNP symptoms are often reported during and after treatment with long-lasting distress. It is unclear how CRF and these PNP symptoms influence each other. This study aimed to explore predictive factors (i.e., PNP symptoms and social-demographic factors) of CRF, and test exploratory path models of the relationships of CRF with PNP symptoms (depression, anxiety, sleep disturbance, pain, and cognitive function) in BCS. METHODS: This paper is part of a larger descriptive, correlational, and cross-sectional study. Validated and reliable instruments assessed CRF, depression, anxiety, sleep disturbance, pain, and cognitive function. Descriptive statistics, Pearson correlation, multiple linear regression models, and path analysis were employed. RESULTS: Patients (N = 373) who reported less bodily pain had worst CRF (r = -0.45, p < .01). Significant predictors of CRF included depression, sleep disorder, bodily pain, perceived cognitive ability, and dispositional (state) optimism. Depression alone accounted for 31% of the variance in CRF. An integrative path model with bodily pain, neuropathic pain, CRF, and depression showed a good fit across different indices (CFI = 0.993, RMSEA = 0.047, 90% CI 0-0.12, SRMR = 0.027). CONCLUSIONS: This study identified significant predictors of CRF and revealed a good fit mediation model with significant pathways for CRF, suggesting that a common etiology may underpin the co-occurrence of CRF with PNP symptoms (pain and depression). However, further investigation with longitudinal design is necessary to explore the causal relationships of these symptoms. Evidence-based strategies/interventions are needed to reduce or eliminate the burden of these symptoms on the lives of BCS.

Correlates of frailty in older female cancer survivors.

INTRODUCTION: Cancer survivors are at risk of frailty because of cancer and its treatment. Understanding the factors that increase the risk of frailty is an important aspect of cancer care for the development of interventions to prevent or manage frailty, thus improving cancer survival and overall quality of life of cancer survivors. This study aimed to identify demographic, clinical, and psychosocial correlates of frailty in older, female cancer survivors. MATERIALS AND METHODS: This is a sub-study focusing on the exploratory aim of a larger cross-sectional study (NURS-IIR-IUSCC-0748). A total of 213 female cancer survivors aged 59-87 years old were included from the parent study in the current analysis. Frailty, the primary outcome, was measured using the Tilburg Frailty Indicator scale. The independent variables were age, relationship status, clinical stage of cancer, treatment type, comorbidity, depression, affect, optimism, stress, and social support. Stepwise linear regression modeling identified the independent variables that were significantly associated with frailty. RESULTS: The final regression model revealed that high patient-reported stress and depression, comorbidity, not being married or living with a partner, and low positive affect were significantly associated with worsening frailty in this population. DISCUSSION: Understanding the context of frailty is important for the design of interventions that target factors known to be associated with frailty in older cancer survivors. Further validation with a larger and a more diverse sample from a broad spectrum of sociodemographic and clinical population would fully account for the multiple independent variables influencing frailty in cancer survivors.

Family Wellbeing and Sexual Health of Patients Receiving Treatment for Prostate Cancer.

Purpose: Prostate cancer and its treatment may affect patients' sexual function and social wellbeing. This study investigated the relationship between social/family wellbeing and sexual health in patients with prostate cancer. Additionally, the moderating effect of clinical characteristics on this relationship was also explored. Patients and Methods: This is a descriptive correlational study using baseline data of a longitudinal study enrolling 137 patients with prostate cancer. Sexual Function (SF) and Sexual Function Distress (SFD) data were collected using the Symptom Index questionnaire. Demographic data were obtained during study intake and clinical data were obtained from chart review. Bivariate correlation determined the correlations among continuous demographic/clinical data, social/family wellbeing, and sexual health. Moderated regression analysis determined the moderating effects of clinical characteristics on the relationship of social/family wellbeing and sexual health. Results: Moderate positive correlation was found between social/family wellbeing and SF, whereas a weak negative correlation was noted between social/family wellbeing and SFD. Depression was significantly correlated with social/family wellbeing and SFD. Both sexual health domains were significantly correlated with Gleason score. A significant difference was noted in the social/family wellbeing and both SF and SFD in participants receiving androgen deprivation therapy (ADT) compared to those not receiving ADT. Concomitant ADT use was the only clinical characteristic found to be a significant moderator of the relationship between social/family wellbeing and SFD, but none of the clinical characteristics was found to have a moderating effect on the relationship of social/family wellbeing and SF. Among patients who were not receiving ADT, high social/family wellbeing was associated with low SFD. Patients who were receiving ADT reported slightly higher SFD despite having higher social/family wellbeing. Conclusion: Ensuring sexual health in patients with prostate cancer requires a comprehensive approach to address factors contributing to sexual health such as side effects of treatment and family wellbeing.

Feasibility of DNA Methylation Age as a Biomarker of Symptoms and Resilience among Cancer Survivors with Multiple Chronic Conditions.

This study aims to examine the feasibility of DNA methylation age as a biomarker for symptoms and resilience in cancer survivors with multiple chronic conditions (MCCs). We included ten participants from our parent study, an ongoing randomized control trial study. Participants' symptoms and resilience were assessed, and peripheral blood was collected. DNA methylation age calculation was performed using DNAge® analysis. Data were analyzed using Spearman's correlation analysis and the Mann-Whitney U test. Participants in the intervention group tended to have a decrease in DNA methylation age and age acceleration after completing an exercise program (mean difference = -0.83 ± 1.26). The change in DNA methylation age was significantly correlated with the change in resilience score (r = -0.897, p = 0.015). The preliminary results suggest that DNA methylation age can be a potential biomarker for improving resilience in cancer survivors with multiple chronic conditions. This finding is limited by the small sample size, and a larger study is needed.

Subacute and Chronic Spinal Cord Injury: A Scoping Review of Epigenetics and Secondary Health Conditions.

Background: Epigenetics studies the impact of environmental and behavioral factors on stable phenotypic changes; however, the state of the science examining epigenomic mechanisms of regulation related to secondary health conditions (SHCs) and neuroepigenetics in chronic spinal cord injury (SCI) remain markedly underdeveloped. Objective: This scoping review seeks to understand the state of the science in epigenetics and secondary complications following SCI. Methods: A literature search was conducted, yielding 277 articles. The inclusion criteria were articles (1) investigating SCI and (2) examining epigenetic regulation as part of the study methodology. A total of 23 articles were selected for final inclusion. Results: Of the 23 articles 52% focused on histone modification, while 26% focused on DNA methylation. One study had a human sample, while the majority sampled rats and mice. Primarily, studies examined regeneration, with only one study looking at clinically relevant SHC, such as neuropathic pain. Discussion: The findings of this scoping review offer exciting insights into epigenetic and neuroepigenetic application in SCI research. Several key genes, proteins, and pathways emerged across studies, suggesting the critical role of epigenetic regulation in biological processes. This review reinforced the dearth of studies that leverage epigenetic methods to identify prognostic biomarkers in SHCs. Preclinical models of SCI were genotypically and phenotypically similar, which is not reflective of the heterogeneity found in the clinical population of persons with SCI. There is a need to develop better preclinical models and more studies that examine the role of genomics and epigenomics in understanding the diverse health outcomes associated with traumatic SCI.

Community-Based Wound Care Programs for Unhoused Individuals.

Wound care management for unhoused individuals is challenging due to the lack of healthcare infrastructure to handle the unique needs of this population. Therefore, we aimed to obtain insights for best practices and to establish a care clinic that is low threshold, community-based and meets the needs of unhoused people. We employed two approaches: (1) conduct a targeted narrative review of the literature of existing or proposed community-based program models that can address the wound care needs of unhoused individuals, and (2) assess cost-effectiveness and describe the results of a survey administered to unhoused clients and their health care providers at a community-based wound care program in Honolulu, Hawai'i. The literature search and screening yielded 11 articles relevant to the topic. Per the literature, existing community-based healthcare programs were successful when: (1) wound care services were incorporated into a broader social/health program, (2) cost-effective, and (3) comprehensive services were provided. Survey results in Honolulu found that the wound care program matched the needs of the targeted population and was cost-effective. Difficulty in following clients until wound closure and the sustainability of the program, particularly the lack of insurance reimbursement for street-based services, were perceived challenges. Additionally, the lack of insurance reimbursement for street-based wound care services continues to impact sustainability. Community-based programs can be successful in addressing the wound care needs of unhoused individuals if they address complex fundamental issues. This paper highlights existing gaps in logistics and policies that must be addressed to meet the specific medical needs of these vulnerable individuals.

Latent class symptom profiles of colorectal cancer survivors with cancer-related cognitive impairment.

PURPOSE: Colorectal cancer (CRC) survivors experience cancer-related cognitive impairment and co-occurring symptoms after cancer treatments. There has been little data to inform the risk factors of complex symptom phenotypes in CRC survivors. OBJECTIVES: To determine if subgroups of CRC survivors after cancer treatments could be identified based on the cognitive impairment and common co-occurring symptoms (depression, anxiety, sleep disturbance, fatigue, and pain); and to explore risk factors (sociodemographic and clinical characteristics, perceived stress, and social support) of these subgroups. METHODS: Latent class profile analysis (LCPA) was used to identify subgroups based on self-reported symptoms in 64 CRC survivors. Cognitive impairment was measured by assessing subjective cognitive function using the Patient-Reported Outcome Measurement Information System (PROMIS) measure. The Kruskal-Wallis test and regression analyses were performed. RESULTS: Three distinct latent classes were identified (Class 1: All Low '28.1%'; Class 2: High Psychological Symptoms (depression/anxiety) '25%'; Class 3: High Somatic Symptoms (fatigue, sleep disturbance, and pain) with High Cognitive Impairment'46.9%'). The pain was the most distinguishable symptom across the latent classes. The high symptom burden group was associated with less time since cancer diagnosis, higher perceived stress levels, and poor emotional social support. CONCLUSION: Our study adds to the information on interindividual variability in symptom experience of CRC survivors with cognitive impairment. Findings suggest a need for increased attention to screening for co-occurring symptoms (e.g., high pain) and future interventions focused on stress management and social support.

Understanding physical activity from a cultural-contextual lens.

This paper aims to emphasize the need to acknowledge unique cultural and contextual meanings of physical activity to improve health outcomes in different communities. Leininger's Sunrise Model was used as the theoretical base to understand the complex cultural and contextual factors that influence physical activity. Beliefs and practices surrounding physical activity are influenced by a variety of cultural and contextual factors. Providing culturally relevant contexts to the meaning of physical activity allows opportunities for improving policies or programs that would engage individuals and communities in physical activity in culturally meaningful ways. Incorporating cultural and contextual factors is critical to promote physical activity, especially in minority and vulnerable communities.

Brain-Derived Neurotrophic Factor rs6265 polymorphism is associated with severe cancer-related fatigue and neuropathic pain in female cancer survivors.

PURPOSE: This study examined the relationships between a single-nucleotide polymorphism (SNP) of brain-derived neurotrophic factor (BDNF) rs6265 and psychoneurological (PN) symptoms in female cancer survivors. METHODS: This secondary analysis examined 393 study participants. In addition to demographic variables, self-reported PN symptom scores (anxiety, bodily pain, depression, fatigue, neuropathic pain, and sleep disturbance) were collected using the Patient-Reported Outcomes Measurement Information System and 36-Item Short-Form Health Survey. Buccal swab samples were collected to obtain genotypes for BDNF rs6265 (Val/Val, Val/Met, or Met/Met). The PN symptom scores were compared across genotypes, and the relationships were examined using a regression model. We also explored correlations between different symptoms within each genotype. RESULTS: Participants with the Met/Met genotype reported significantly worse cancer-related fatigue and neuropathic pain, which was confirmed by rank-based regression analysis. In addition, cancer-related fatigue was correlated with other PN symptoms, particularly depression. These correlations were stronger in study participants with the Met/Met genotype than those with other genotypes. CONCLUSION: Our study suggests that female cancer survivors with the Met/Met genotype of BDNF rs6265 are likely to experience worse cancer-related fatigue and neuropathic pain and that cancer-related fatigue is a good predictor of co-occurring PN symptoms in this population. IMPLICATIONS FOR CANCER SURVIVORS: Our findings advance the scientific community's understanding of cancer-related PN symptoms experienced by female cancer survivors, especially the unique role of BDNF rs6265 polymorphism in these symptoms. Our findings offer valuable insights for clinical practice that the symptom experience among female cancer survivors may vary based on BDNF genotypes.

Changes in cardiorespiratory function and fatigue following 12 weeks of exercise training in women with systemic lupus erythematosus: a pilot study.

OBJECTIVE: In patients with systemic lupus erythematosus (SLE), fatigue is a debilitating symptom with poorly understood pathophysiology. Cardiorespiratory dysfunction has been hypothesised as a contributor to SLE-fatigue. The purpose of this exploratory study was to examine changes in cardiorespiratory function, following an exercise training programme in women with SLE, together with patient reported outcomes and other pathophysiological measures that may underlie SLE-fatigue. METHODS: Sixteen women with SLE and fatigue (Fatigue Severity Scale (FSS) ≥3) were enrolled in a supervised aerobic exercise training programme of vigorous intensity. The primary outcome was time to reach anaerobic threshold (AT-Time) during a cardiopulmonary exercise test (CPET). Secondary outcomes included changes in the 10-minute walk test (10MWT), FSS scores and the Patient Reported Outcomes Measurement Information System (PROMIS-57) survey. Mitochondrial function was assessed by the oxygen consumption rate (OCR)/extracellular acidification rate (ECAR) metabolic potential ratio. RESULTS: Following 12 weeks of exercise training, AT-Time increased by 93±82 (mean±SD) s (p<0.001), 10MWT increased by 84±66 m (p<0.001) and peak oxygen uptake (VO2) increased by 1.4±2.0 mL/kg/min (p=0.013). There were improvements in FSS score (-1.4±1.0, p<0.0001) and in most of the PROMIS-57 domains. The decrease in FSS scores correlated with an increase in the OCR/ECAR ratio (Pearson's correlation r=-0.59, p=0.03). A subset of subjects (9/15) had significant reduction in their Interferon Stimulated Genes (ISG) (p=0.007) accompanied by a significant increase in the OCR/ECAR ratio (p=0.013). CONCLUSIONS: Cardiorespiratory function was improved in concomitance with reductions in fatigue following a 12-week aerobic exercise programme. The reduction in fatigue scores correlated with improvements in mitochondrial function.

Blood-based biomarkers of cancer-related cognitive impairment in non-central nervous system cancer: A scoping review.

This scoping review was designed to synthesize the extant literature on associations between subjective and/or objective measures of cancer-related cognitive impairment (CRCI) and blood-based biomarkers in adults with non-central nervous system cancers. The literature search was done for studies published from the start of each database searched (i.e., MEDLINE, Embase, PsycINFO, Cumulative Index to Nursing and Allied Health Literature, Cochrane Central Register of Controlled Trials, grey literature) through to October 20, 2021. A total of 95 studies are included in this review. Of note, a wide variety of biomarkers were evaluated. Most studies evaluated patients with breast cancer. A variety of cognitive assessment measures were used. The most consistent significant findings were with various subjective and objective measures of CRCI and levels of interleukin-6 and tumor necrosis factor. Overall, biomarker research is in an exploratory phase. However, this review synthesizes findings and proposes directions for future research.

BDNF Val66Met Polymorphism Reduces the Fatigue-Like Effects of 5-Fluorouracil on Voluntary Wheel-Running Activity in Mice.

Fatigue is a persistent and debilitating symptom following cancer treatments such as chemotherapy. Recent clinical studies have suggested a common single-nucleotide polymorphism of brain-derived neurotrophic factor (BDNF), Val66Met (rs6265), may be related to the severity of fatigue following cancer treatment. In this study, we tested transgenic mice homozygous for the human Val66Met BDNF gene and wild-type controls. We injected three doses of 5-fluorouracil (5FU) as a model of chemotherapy treatment, and we used changes in voluntary wheel running activity (VWRA) as a measure of fatigue-like behavior. Prior to 5FU injection, we found that during the baseline wheel-running period, the Val66Met mice lost more weight than WT controls. We next administered 5FU and saw a robust fatigue-like phenotype that lasted about 2 weeks. During the first week, the fatigue-like phenotype was less severe in the Val66Met mice and unrelated to the age of the mice. In contrast, during the second week after 5FU treatment, the fatigue-like phenotype was unrelated to the BDNF genotype but was more severe in middle aged mice compared to young mice. We conclude that the BDNF polymorphism may play a direct, protective role against chemotherapy-induced fatigue.

Differences in Circulating Extracellular Vesicle and Soluble Cytokines in Older Versus Younger Breast Cancer Patients With Distinct Symptom Profiles.

Because extracellular vesicle (EV)-associated cytokines, both encapsulated and surface bound, have been associated with symptom severity, and may vary over the lifespan, they may be potential biomarkers to uncover underlying mechanisms of various conditions. This study evaluated the associations of soluble and EV-associated cytokine concentrations with distinct symptom profiles reported by 290 women with breast cancer prior to surgery. Patients were classified into older (≥60 years, n = 93) and younger (< 60 years, n = 197) cohorts within two previously identified distinct symptom severity profiles, that included pain, depressive symptoms, sleep disturbance, and fatigue (i.e., High Fatigue Low Pain and All Low). EVs were extracted using ExoQuick. Cytokine concentrations were determined using Luminex multiplex assay. Mann Whitney U test evaluated the differences in EV and soluble cytokine levels between symptom classes and between and within the older and younger cohorts adjusting for Karnofsky Performance Status (KPS) score, body mass index (BMI), and stage of disease. Partial correlation analyses were run between symptom severity scores and cytokine concentrations. Results of this study suggest that levels of cytokine concentrations differ between EV and soluble fractions. Several EV and soluble pro-inflammatory cytokines had positive associations with depressive symptoms and fatigue within both age cohorts and symptom profiles. In addition, in the older cohort with High Fatigue Low Pain symptom profile, EV GM-CSF concentrations were higher compared to the All Low symptom profile (p < 0.05). Albeit limited by a small sample size, these exploratory analyses provide new information on the association between cytokines and symptom profiles of older and younger cohorts. Of note, unique EV-associated cytokines were found in older patients and in specific symptom classes. These results suggest that EVs may be potential biomarker discovery tools. Understanding the mechanisms that underlie distinct symptom class profiles categorized by age may inform intervention trials and offer precision medicine approaches.

Exploratory Analysis of Associations Between Whole Blood Mitochondrial Gene Expression and Cancer-Related Fatigue Among Breast Cancer Survivors.

BACKGROUND: Cancer-related fatigue is a prevalent, debilitating, and persistent condition. Mitochondrial dysfunction is a putative contributor to cancer-related fatigue, but relationships between mitochondrial function and cancer-related fatigue are not well understood. OBJECTIVES: We investigated the relationships between mitochondrial DNA (mtDNA) gene expression and cancer-related fatigue, as well as the effects of fish and soybean oil supplementation on these relationships. METHODS: A secondary analysis was performed on data from a randomized controlled trial of breast cancer survivors 4-36 months posttreatment with moderate-severe cancer-related fatigue. Participants were randomized to take 6 g fish oil, 6 g soybean oil, or 3 g each daily for 6 weeks. At pre- and postintervention, participants completed the Functional Assessment of Chronic Illness Therapy-Fatigue questionnaire and provided whole blood for assessment of mtDNA gene expression. The expression of 12 protein-encoding genes was reduced to a single dimension using principal component analysis for use in regression analysis. Relationships between mtDNA expression and cancer-related fatigue were assessed using linear regression. RESULTS: Among 68 participants, cancer-related fatigue improved and expression of all mtDNA genes decreased over 6 weeks with no effect of treatment group on either outcome. Participants with lower baseline mtDNA gene expression had greater improvements in cancer-related fatigue. No significant associations were observed between mtDNA gene expression and cancer-related fatigue at baseline or changes in mtDNA gene expression and changes in cancer-related fatigue. DISCUSSION: Data from this exploratory study add to the growing literature that mitochondrial dysfunction may contribute to the etiology and pathophysiology of cancer-related fatigue.