Polymorphisms in Cytokine Genes Are Associated With Higher Levels of Fatigue and Lower Levels of Energy in Women After Breast Cancer Surgery

Chronic Decrements in Energy in Women with Breast Cancer are Associated with Cytokine Gene Polymorphisms

OBJECTIVES

Decrements in energy were found in 67% of women who underwent breast cancer surgery. However, no information is available on chronic decrements in energy and associations with inflammation. Purposes were to identify latent classes of patients with distinct average energy profiles from prior to through 12 months after breast cancer surgery; evaluate for differences in demographic and clinical characteristics between the two extreme average energy classes; and evaluate for polymorphisms for cytokine genes associated with membership in the Low energy class.

METHODS

Women (n = 397) completed assessments of energy prior to and for 12 months following breast cancer surgery. Growth mixture modeling was used to identify classes of patients with distinct average energy profiles. Eighty-two single nucleotide polymorphisms (SNPs) among 15 cytokine genes were evaluated.

RESULTS

Three distinct energy profiles were identified (ie, Low [27.0%], Moderate [54.4%], Changing [18.6%]). Data from patients in the Low and Moderate energy classes were used in the candidate gene analyses. Five SNPs and one haplotype in six different genes remained significant in logistic regression analyses (ie, interleukin [IL]-1β rs1143623, IL1 receptor 1 rs3917332 IL4 rs2243263, IL6 HapA1 [that consisted of rs1800795, rs2069830, rs2069840, rs1554606, rs2069845, rs2069849, and rs2069861], nuclear factor kappa beta subunit 1 rs170731, tumor necrosis factor rs1799964). For several SNPs for IL6, expression quantitative trait locis were identified in subcutaneous and visceral adipose tissue and thyroid tissue. In addition, skeletal muscle was identified as an expression quantitative trait loci for nuclear factor kappa beta subunit 1.

CONCLUSIONS

Findings suggest that cytokine genes are involved in the mechanisms that underlie chronic decrements in energy in women following breast cancer surgery. Given the roles of subcutaneous and visceral adipose and thyroid tissues in metabolism and energy balance, the findings related to IL6 suggest that these polymorphisms may have a functional role in the development and maintenance of chronic decrements in energy.

The impact of non- and anthracycline-based chemotherapy on fatigue in breast cancer survivors: results from WF-97415

PURPOSE

To examine the differential effect of non- and anthracycline-based chemotherapy on fatigue over 12 months post-diagnosis among breast cancer survivors.

METHODS

This study is based on a prospective Wake Forest NCI Community Oncology Research Program (NCORP) multicenter cohort study (WF-97415) of women with stage I to III breast cancer and non-cancer controls. Analyses compared those: 1) receiving, or 2) not receiving anthracycline chemotherapy, 3) receiving aromatase inhibitors (AIs) without chemotherapy, with 4) a comparator group without a history of cancer. In-person clinic assessments were conducted at: baseline (prior to chemotherapy or start of AI therapy), and 3 and 12 months after baseline. The Functional Assessment of Chronic Illness Therapy-Fatigue scale was the primary outcome. Estimated least squares means by group using mixed models with a random subject effect, fixed effects of time and group, and the interaction between time and group was used to compare groups across time, controlling for age, comorbidities, and treatment variables.

RESULTS

Among 284 women (mean age = 53.4 years, sd 11.9 years), there was a significant (p < 0.0001) group by time interaction, with a sharp increase in fatigue at 3 months in the two chemotherapy groups in comparison to the non-chemotherapy and non-cancer controls. The two chemotherapy groups did not significantly differ in fatigue at any time point.

CONCLUSION

Women with breast cancer who receive non- or anthracycline-based chemotherapy experience similar trends in and levels of fatigue within the first year of treatment and greater fatigue than women receiving AIs alone or women without breast cancer.

Multidimensional Model of Energy in Patients With Cancer

OBJECTIVES

Evidence suggests that energy is a distinct symptom from fatigue in patients with cancer. The purpose of this paper is to present the Multidimensional Model of Energy in Patients with Cancer (MMEPC) that is based on emerging evidence and to make recommendations for clinical practice and future research.

METHODS

The literature was reviewed to determine various factors associated with variations in energy in patients with cancer. In addition, some of the emerging evidence in the model is supported by studies of energy in the general population and in patients with other chronic conditions.

RESULTS

Based on a review of the literature, specific concepts in the MMEPC include: person factors, clinical factors, cancer-related factors, biological factors, factors associated with energy balance, and co-occurring symptoms. The evidence to support the association between each of these factors and variations in energy levels in patients with cancer is described and synthesized.

CONCLUSION

This article provides emerging evidence on factors that influence variations in energy levels in patients with cancer. While the fundamental biobehavioral and biologic mechanisms that underlie variations in energy levels are not well understood, the model can be used to design pre-clinical and clinical studies of energy in patients with cancer. In addition, while emerging evidence supports the hypothesis that fatigue and energy are distinct symptoms, additional research on common and distinct risk factors and underlying mechanisms is warranted to be able to develop and test precision interventions for one or both symptoms.

IMPLICATIONS FOR NURSING PRACTICE

The risk factors (eg, being female, sleep quality) associated with variations in energy levels in patients with cancer identified in this paper have important clinical implications. Clinicians can use the identified risk factors to guide their assessments; identify high-risk patients with decrements in energy decrement; and develop targeted energy conservation interventions for the patients.

Cancer symptom cluster research in pediatric oncology: a work in progress

In the 21st century, advances in basic research have provided new insights in the field of pediatric oncology. Pediatric patients tend to experience higher levels of distressing symptoms, which together form a symptom cluster. In clinical practice, these symptom clusters are reported daily by children and adolescents with cancer. Translational research has emerged as the translation of new knowledge from basic science into clinical practice. Understanding how neuroimmunoendocrine pathways regulate cancer development and the aspects underlying the specific therapies, such as chemotherapy and immunotherapy, is an important frontier for future research in pediatric oncology. The goal of translational research is to show how different variables in tumor and patient characteristics explain the differential effects of interventions, as translational research provides new insights into the management of cancer symptoms in children and adolescents with cancer. Together, this approach could lead to improvements in pediatric oncology care worldwide.

Fatigue, Toll-Like Receptor 4, and Pro-Inflammatory Cytokines in Adults With Subarachnoid Hemorrhage: A 6-Month Longitudinal Study

BACKGROUND

Fatigue is prevalent in subarachnoid hemorrhage (SAH) survivors. Biological mechanisms underlying fatigue post-SAH are not clear. Inflammation may contribute to the development of fatigue. This study aimed to examine the associations between inflammatory markers and fatigue during the first 6 months post-SAH. Specific biomarkers examined included both early and concurrent expression of Toll-Like Receptor 4 (TLR4) messenger RNA (mRNA) and plasma concentrations of pro-inflammatory cytokines, Tumor Necrosis Factor-alpha (TNF-α), Interleukin (IL)1β, and IL6.

METHODS

We conducted a 6-month longitudinal study with a convenience sample of 43 SAH survivors. We collected blood samples on days 2, 3, and 7 and 2, 3, and 6 months post-SAH to assess biomarkers. Fatigue was assessed by the PROMIS Fatigue Scale at 2, 3, and 6 months. Linear mixed models were used to test the associations between early (days 2, 3, and 7) and concurrent (2, 3, and 6 months) TLR4 mRNA expression (TagMan gene expression assays) and TNF-α, IL1β, and IL6 plasma concentrations (multiplex assays) and concurrent fatigue.

RESULTS

28% of SAH survivors experienced fatigue during the first 6 months post-SAH. Fatigue levels in SAH survivors were higher than those of the U.S. population and consistent during the 6 months. Experience of fatigue during the 6 months post-SAH was associated with higher IL1β plasma concentrations on day 7 and IL1β, IL6, and TNF-α plasma concentrations during the 6 months post-SAH.

CONCLUSION

Inflammation appears to underlie the development of fatigue in SAH survivors.

Recent evidence and progress for developing precision nursing in symptomatology: A scoping review

AIM

To summarize the omics results of symptomatic research that can help nurses identify intervention targets and design precision interventions for pain, mental health, cognitive impairment, sleep disorder, fatigue, lymphedema, and quality of life, so as to provide a comprehensive summary of help and inspire to precision nursing.

METHODS

CINAHL, PubMed, Web of Science, and ScienceDirect databases were searched. Retrieval time was from January 2012 to December 2021. Symptomatology research applying omics that can be used to guide nurses in designing targeted interventions was included.

RESULTS

Forty-six studies were included in the final review. Symptomatology research that can be integrated with nursing science to develop precision nursing focused on pain, mental health, cognitive impairment, sleep disorder, fatigue, lymphedema, and quality of life. Most studies were related to cognitive impairment (n = 10; 21.74%), pain (n = 9; 19.57%), and mental health (n = 8; 17.39%). Moreover, the included studies involved various omics technologies, such as whole genome, epigenome, transcriptome, proteome, and metabolome.

CONCLUSION

The rapid development of various omic technologies promotes symptomatology research, which can help nurses fully understand the information of patients. Phenotypic characteristics and biomarkers shown in symptomatology research help nurses identify intervention targets and develop individualization interventions, so as to prevent and reduce symptoms and improve the quality of life.

IMPLICATION FOR NURSING AND HEALTH POLICY

This scoping review is the first synthesis of all peer-reviewed literature to summarize and provide important information and references from the omic results of symptomatology studies to develop precision nursing, highlighting the status and development of precision nursing. Nursing education policies should introduce the development and importance of precision nursing. Further research could consider investing more attention in precision nursing. Nursing researchers can carry out some studies applying omics technology to explore more biomarkers, helping guide the formulation of clinical intervention for symptoms.

Distinct Cognitive Function Profiles Are Associated With a Higher Presurgery Symptom Burden in Patients With Breast Cancer

BACKGROUND

Cancer-related cognitive impairment (CRCI) is a common symptom in patients with breast cancer. In our previous study of 397 women with breast cancer, we identified 3 groups of patients with distinct CRCI profiles (ie, high, moderate, and low-moderate attentional function). Compared with the other 2 classes, the low-moderate class was younger, had more comorbidities, and with lower functional status.

OBJECTIVES

In this study, we expand on this work and evaluate for differences among these latent classes in the severity of psychological (depression and anxiety) and physical (fatigue, decrements in energy, sleep disturbance, and pain) symptoms before surgery.

METHODS

Cancer-related cognitive impairment was assessed using the Attentional Functional Index from before through 6 months after surgery. Lower Attentional Functional Index scores indicate higher levels of CRCI. Psychological and physical symptoms were assessed with valid instruments. Parametric and nonparametric tests were used to evaluate for differences in symptom severity scores among the latent classes.

RESULTS

Approximately 60% of patients experienced CRCI (ie, moderate and low-moderate classes). Significant differences were found among the 3 classes in the severity of trait and state anxiety, depressive symptoms, fatigue, and sleep disturbance (ie, high < moderate < low-moderate). In addition, compared with the other 2 classes, the low-moderate class reported higher pain interference scores.

CONCLUSIONS

These findings suggest that women with clinically meaningful levels of persistent CRCI have a relatively high symptom burden before surgery.

IMPLICATIONS FOR PRACTICE

Clinicians need to routinely perform preoperative assessments of CRCI and associated symptoms and initiate therapeutic interventions.

Sleep disturbance and decrements in morning energy contribute to a higher symptom burden in oncology patients

OBJECTIVE/BACKGROUND

An emerging area of research is the relationship between sleep disturbance and decrements in energy. Given the paucity of research on the co-occurrence of these two symptoms, study purposes were to identify subgroups of oncology patients with distinct joint sleep disturbance AND morning energy profiles and evaluate for differences among the subgroups in demographic, clinical, and sleep disturbance characteristics, as well as the severity of other common symptoms and QOL outcomes.

PATIENTS/METHODS

Patients (n = 1336) completed measures of sleep disturbance and energy 6 times over two cycles of chemotherapy. All of the other measures were completed at enrollment. Latent profile analysis was used to identify the distinct joint sleep disturbance and morning energy profiles.

RESULTS

Three distinct profiles were identified (i.e., Low Sleep Disturbance and High Morning Energy (Normal, 20.6%), Moderate Sleep Disturbance and Low Morning Energy (Moderately Severe, 52.1%), Very High Sleep Disturbance and Very Low Morning Energy (Very Severe, 27.3%). Compared to Normal class, other two classes were more likely to be female, less likely to be employed, and had higher comorbidity burden and poorer functional status. Symptom scores and QOL outcomes exhibited a dose response effect (i.e., as the profile worsened, symptom scores increased and QOL scores decreased).

CONCLUSIONS

Given the associations between sleep disturbance and decrements in energy and a higher symptom burden, poorer QOL outcomes, and increased mortality, assessment of these two symptoms needs to be a high priority for clinicians and appropriate interventions initiated.

The Cancer Genomic Integration Model for Symptom Science (CGIMSS): A Biopsychosocial Framework

Current nursing research has characterized symptom clusters and trajectories in individuals with breast cancer. The existing literature describes the relationship between symptoms and biological variables and the potential moderating effects of individual and social factors. The genomic profiling of breast cancer has also been an area of much recent research. Emerging evidence indicates that incorporating cancer genomics into symptom science research can aid in the prognostication of symptoms and elucidate targets for symptom management interventions. The aim of this paper is to outline a model to integrate cancer genomics into symptom science research, illustrated using breast cancer and psychoneurological (PN) symptoms as an example. We present a review of the current literature surrounding breast cancer genomics (specifically cancer genomic instability) and the biological underpinnings of the PN symptom cluster. Advances in both of these areas indicate that inflammation may serve as the bridge between cancer genomics and the PN symptom cluster. We also outline how the integration of cancer genomics into symptom science research synergizes with current research of individual and social factors in relation to symptoms. This model aims to provide a framework to guide future biopsychosocial symptom science research that can elucidate new predictive methods and new targets for intervention.

[Immune mechanisms of complicity of somatic pathology in the pathogenesis of mental disorders]

Understanding the mechanisms of the relationship between the nervous and immune systems within the framework of the concept of the key role of inflammation, taking into account the involved genetic factors in the development of a wide range of combined forms of somatic and mental diseases, is of interest for research as well as for the development of new approaches to early diagnosis and more effective treatment of these diseases. This review analyzes the immune mechanisms of the development of mental disorders in patients with somatic diseases, in particular, the transmission of an inflammatory signal from the periphery to the CNS and the implementation of the influence of inflammatory factors on neurochemical systems that determine the characteristics of mental functioning. Particular attention is paid to the processes underlying the disruption of the blood-brain barrier caused by peripheral inflammation. Modulation of neurotransmission, changes in neuroplasticity, changes in regional activity of the brain in areas associated with the functions of threat recognition, cognitive processes and memory function, the effect of cytokines on the hypothalamic-pituitary-adrenal system are considered as mechanisms of action of inflammatory factors in the brain. The need to take into account variations in the genes of pro-inflammatory cytokines, which may be the cause of increased genetic vulnerability associated with the risk mental disorders in patients suffering from a certain somatic disease, is emphasized.

Time course and predictors of persistent cancer-related fatigue in long-term breast cancer survivors: a prospective observational study

PURPOSE

The present study investigated whether the level of cancer-related fatigue (CRF) after finishing oncology treatment was related to higher levels of persistent CRF and its relationship with both functional and psychological disturbances. Second, to identify potential predictors of persistent CRF.

METHODS

Eighty BC survivors were classified into non-fatigued (≤ 3.9) or fatigued (≥ 4), according to their Piper Fatigue Scale total score after finishing oncology treatment. The time course of fatigue and the impact on its domains, pain, mood state, perceived physical fitness, the level of physical activity, and quality of life were assessed at ≥ 5 years.

RESULTS

Women classified as fatigued after finishing oncology treatment had not only a higher prevalence of persistent CRF (41.2%) at the reassessment, but also greater levels of pain (P = .006 to .048) and mood disturbances (P = .007 to .015), and lower levels of physical fitness condition (P = .002 to .039) and quality of life (P < .001 to < .05) over time. Regression analyses revealed that "sadness/depression," "global health status," "physical activity level," and "type of treatment" were significant predictors of persistent CRF (r² = .692).

CONCLUSION

Higher levels of CRF implied greater levels of persistent CRF and a lower functional and psychological profile over time. 69.2% of of persistent CRF was explained.

Development and Validation of a Predictive Model of Severe Fatigue After Breast Cancer Diagnosis: Toward a Personalized Framework in Survivorship Care

PURPOSE

Fatigue is common and troublesome among breast cancer survivors; however, limited tools exist to predict its risk.

PATIENTS AND METHODS

Participants with stage I-III breast cancer were prospectively included from CANTO (ClinicalTrials.gov identifier: NCT01993498), collecting longitudinal data at diagnosis (before the initiation of any cancer treatment) and 1 (T1), 2 (T2), and 4 (T3) years after diagnosis. The main outcome was severe global fatigue at T2 (score ≥ 40/100, European Organisation for Research and Treatment of Cancer (EORTC) Quality of Life Questionnaire-C30). Analyses at T3 were exploratory. Secondary outcomes included physical, emotional, and cognitive fatigue (EORTC Quality of Life Questionnaire-FA12). Multivariable logistic regression models retained associations with severe fatigue by bootstrapped Augmented Backward Elimination. Validation methods included 10-fold internal cross-validation, overoptimism-corrected area under the receiver operating characteristic curves, and external validation.

RESULTS

Among 5,640, 5,000, and 3,400 patients at T1, T2, and T3, respectively, the prevalence of post-treatment severe global fatigue was 35.6%, 34.0%, and 31.5% in the development cohort. Retained risk factors for severe global fatigue at T2 were severe pretreatment fatigue (adjusted odds ratio v no 3.191 [95% CI, 2.704 to 3.767]); younger age (for 1-year decrement 1.015 [1.009 to 1.022]), higher body mass index (for unit increment 1.025 [1.012 to 1.038]), current smoking behavior (v never 1.552 [1.291 to 1.866]), worse anxiety (v noncase 1.265 [1.073 to 1.492]), insomnia (for unit increment 1.005 [1.003 to 1.007]), and pain at diagnosis (for unit increment 1.014 [1.010 to 1.017]), with an area under the receiver operating characteristic curve of 0.73 (95% CI, 0.72 to 0.75). Receipt of hormonal therapy was a risk factor for severe fatigue at T3 (v no 1.448 [1.165 to 1.799]). Dimension-specific risk factors included body mass index for physical fatigue and emotional distress for emotional and cognitive fatigue.

CONCLUSION

We propose a predictive model to assess fatigue among breast cancer survivors, within a personalized survivorship care framework. This may help clinicians to provide early management interventions or to correct modifiable risk factors and offer more tailored monitoring and education to patients at risk of severe post-treatment fatigue.

Symptom trajectories in breast cancer survivors: growth mixture analysis of patient-reported pain, fatigue, insomnia, breast and arm symptoms

BACKGROUND

Variations in symptom development among breast cancer (BC) survivors are understudied. We examined: (Q1) Symptom trajectories of pain, fatigue, insomnia, breast, and arm symptoms in BC survivors, (Q2) possible patterns or cluster-like associations between trajectory classification of different symptoms, and (Q3) characteristics of survivors assigned to high-burden symptom trajectories.

MATERIAL AND METHODS

Participants were 968 women (mean age = 59.6 years) treated for early-stage BC and followed across a three-year postoperative period. As part of routine follow-up procedures, patients reported symptom burden and functioning levels at each hospital visit using the European Organisation for Research and Treatment of Cancer (EORTC) Quality of Life Questionnaire (QLQ-C30) and the BC-specific module (QLQ-BR-23). Growth mixture modeling (GMM) analysis was used to differentiate potential subgroups of individuals with similar longitudinal symptom patterns, i.e., symptom trajectories (Q1). With this approach, groups experiencing persistent, highly distressing cancer- and treatment-related late effects (LEs) may be identified. Latent class analysis (LCA) was used for Q2 and logistic regression analysis for Q3.

RESULTS

GMM identified two relatively parallel trajectories across the tested symptoms: The majority of the sample exhibited a low-burden symptom trajectory (74.4-89.2%) and a minority by a high-burden symptom trajectory (10.8-25.6%). LCA revealed that approximately one in five women (18.8%) were likely to be members of the high-burden symptom trajectory across all tested symptoms. In addition to a high probability of being burdened over time across multiple symptoms, these women were also characterized by poorer self-reported physical and social functioning.

CONCLUSION

A substantial minority followed a high-burden symptom trajectory for several years following BC treatment. Associations were found in trajectory classification across symptoms, indicating that cancer-related LEs appear in clusters of multiple concurrent symptoms.

Involvement of INF-γ functional single nucleotide polymorphism +874 T/A (rs2430561) in breast cancer risk

According Global Cancer Statistics 2020 GLOBOCAN estimates female breast cancer was found as the most commonly diagnosed cancer, with an estimated 2.3 million new cases (11.7%), and the fourth leading cause (6.9%) of cancer death among women worldwide. Identification of new diagnostic marker sharply characterize the tumor feature is intensive need. The present work was performed to investigate the involvement of the INF-γ + 874 T/A gene polymorphism in different breast cancer prognostic factors. Polymorphism detection analysis was performed on 163 subjects from breast cancer patients, 79 with inflamed cells of breast patients and 144 controls. The gene polymorphism was detected using the amplification refractory mutation system- polymerase chain reaction method (ARMS-PCR). The distribution of INF-γ T + 874A gene polymorphism shows strong significant association between INF-γ + 874 T/A genotypes TT in BC patients (ORTT: 6.41 [95% CI = 2.72-15.1] P < 0.0001) as well as strong significant association regarding T allele (ORT: 1.99 [95% CI = 1.43-2.76] P < 0.0001) when compared to the healthy control. In ICB group the strong association was noted with INF-γ + 874 T/A genotypes AT genotype (ORAT: 2.28 [95% CI = 1.22-4.29] P = 0.007). From the different histological BC hormonal markers the human epidermal growth factor receptor 2 (HER2) was showing significant association in INF-γ + 874 T/A genotypes TT (P = 0.03) and recessive model (TT versus AA + AT P = 0.03). Concerning different BC prognostic models, the poor prognostic one of luminal B, (ER+ve PR+ve Her2+ve) show significant association in the host INF-γ + 874 T/A genotype (TT, P = 0.03) and recessive model (TT versus AA + AT P = 0.02) when compared to the good prognostic hormonal status luminal A model, (ER+ve PR+ve Her2-ve). It seems that this is the first study that interested in correlate the INF-γ + 874 T/A gene polymorphisms in Egyptian BC patients. T allele, TT genotype and recessive model of the INF-γ + 874 T/A gene variants were documented as risk factors for BC pathogenesis. It may be used as practical biomarker to guide the BC carcinogenesis and risk process.

Genetic associations of fatigue and other symptoms following breast cancer treatment: A prospective study

Background

Cancer-related fatigue, mood disturbances, pain and cognitive disturbance are common after adjuvant cancer therapy, but vary considerably between individuals despite common disease features and treatment exposures. A genetic basis for this variability was explored in a prospective cohort.

Methods

Physical and psychological health of women were assessed prospectively following therapy for early stage breast cancer with self-report questionnaires. Participation in a genetic association sub-study was offered. Indices for the key symptom domains of fatigue, pain, depression, anxiety, and neurocognitive difficulties were empirically derived by principal components analysis from end-treatment questionnaires, and then applied longitudinally. Genetic associations were sought with functional single nucleotide polymorphisms (SNPs) in pro- and anti-inflammatory cytokine genes - tumour necrosis factor (TNF)-α (−308 ​GG), interferon (IFN)-ɣ (+874 ​TA), interleukin (IL)-10 (1082 ​GA and −592 CA), IL-6 (−174 ​GC), IL-1β (−511 ​GA).

Results

Questionnaire data was available for 210 participants, of whom 111 participated in the genetic sub-study. As expected, symptom domain scores generally improved over several months following treatment completion. Tumour and adjuvant treatment related factors were unassociated with either severity or duration of the individual symptom domains, but severity of symptoms at end-treatment was strongly associated with duration for each domain (all p ​< ​0.05). In multivariable analyses, risk genotypes were independently associated with: fatigue with IL-6 -174 ​GG/GC and IL-10 -1082 GG; depression and anxiety with IL-10 -1082 AA; neurocognitive disturbance: TNF-α −308 GG; depression IL-1β (all p ​< ​0.05). The identified SNPs also had cumulative effects in prolonging the time to recovery from the associated symptom domain.

Conclusions

Genetic factors contribute to the severity and duration of common symptom domains after cancer therapy.

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Common symptoms following breast cancer treatment can be grouped into symptom domains.

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Symptom domains are useful to describe patterns and trajectories of symptoms following breast cancer treatment.

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Cytokine gene polymorphisms are associated with the severity and duration of symptom domains following cancer treatment.

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The symptom severity at final treatment predicts the duration of symptoms.

Do all patients with cancer experience fatigue? A longitudinal study of fatigue trajectories in women with breast cancer

BACKGROUND

Fatigue is a common and expected side effect of cancer treatment. However, the majority of studies to date have focused on average levels of fatigue, which may obscure important individual differences in the severity and course of fatigue over time. The current study was designed to identify distinct trajectories of fatigue from diagnosis into survivorship in a longitudinal study of women with early-stage breast cancer.

METHODS

Women with stage 0 to stage IIIA breast cancer (270 women) were recruited before (neo)adjuvant therapy with radiotherapy, chemotherapy, and/or endocrine therapy and completed assessments at baseline; posttreatment; and at 6 months, 12 months, and 18 months of follow-up. Growth mixture modeling was used to identify trajectories of fatigue, and differences among the trajectory groups with regard to demographic, medical, and psychosocial variables were examined.

RESULTS

Five distinct trajectories of fatigue were identified: Stable Low (66%), with low levels of fatigue across assessments; Stable High (13%), with high fatigue across assessments; Decreasing (4%), with high fatigue at baseline that resolved over time; Increasing (9%), with low fatigue at baseline that increased over time; and Reactive (8%), with increased fatigue after treatment that resolved over time. Both psychological and treatment-related factors were found to be associated with fatigue trajectories, with psychological factors most strongly linked to high fatigue at the beginning of and over the course of treatment.

CONCLUSIONS

There is considerable variability in the experience of fatigue among women with early-stage breast cancer. Although the majority of women report relatively low fatigue, those with a history of depression and elevated psychological distress may be at risk of more severe and persistent fatigue.

Morning Fatigue Severity Profiles in Oncology Outpatients Receiving Chemotherapy

BACKGROUND

Morning fatigue is a distinct symptom experienced during chemotherapy that demonstrates significant interindividual variability.

OBJECTIVES

The aims of this study were to identify subgroups with distinct morning fatigue profiles and evaluate how these subgroups differed by demographic, clinical, and symptom characteristics.

METHODS

Outpatients (N = 1332) with breast, gastrointestinal, gynecological, or lung cancer completed questionnaires 6 times over 2 cycles of chemotherapy. Morning fatigue was assessed with the Lee Fatigue Scale. Latent profile analysis was used to identify distinct morning fatigue profiles.

RESULTS

Four morning fatigue profiles (ie, very low, low, high, and very high) were identified. In the high and very high classes, all 6 morning fatigue scores were higher than the clinical cutoff score. Compared with those in the very low and low classes, patients in the very high class were younger and not married/partnered; lived alone; had higher incomes, higher comorbidity, and higher body mass index; and did not exercise regularly. Across the 4 classes, functional status and attentional function scores decreased and anxiety, depression, sleep disturbance, morning fatigue, and evening fatigue scores increased across the 2 cycles.

CONCLUSION

Results provide insights into modifiable risk factors for morning fatigue. These risk factors can be used to develop more targeted interventions.

IMPLICATIONS FOR PRACTICE

Patients in the high and very high morning fatigue classes experienced high symptom and comorbidity burdens and significant decrements in functional status. Using this information, clinicians can identify patients who are at an increased risk for higher levels of morning fatigue and prescribe interventions to improve this devastating symptom.

Factors of the evolution of fatigue dimensions in patients with breast cancer during the 2 years after surgery

Women with breast cancer are increasingly being cured of the disease but fatigue remains the most frequently reported symptom. The aims of our study were to identify distinct trajectories in four fatigue dimensions during 2 years after breast cancer surgery and to explore the demographic, clinical and personality characteristics associated with these profiles. We included women from the prospective longitudinal multicenter FATSEIN cohort in France. They completed the Multidimensional Fatigue Inventory for nine follow-ups over 24 months after surgery. A group-based trajectory model identified distinct trajectories in each fatigue dimension. Multinomial logistic regression determined the factors associated with each profile. From the 459 women followed, 3-5 fatigue trajectories were revealed in each fatigue dimension, from its absence to its severest degree. In our multivariate analysis, the risk of severe fatigue was decreased in all dimensions by a high quality of life before surgery (measured by the European Organization for Research and Treatment of Cancer 30-item QoL questionnaire; e.g., for general and physical fatigue: OR = 0.93, 95% CI 0.91, 0.96), especially a high physical and emotional functions for general and physical fatigue, and a high cognitive function for mental fatigue. Both severe mental fatigue and severely reduced motivation worsened with low optimism before surgery (e.g., for mental fatigue: OR = 0.93, 95% CI 0.89, 0.97). Severely reduced activities increased by having chemotherapy (OR = 9.41, 95% CI 2.28, 38.79). Targeting women at risk for severe fatigue can provide early preventive and curative treatment and appropriate psychological support.

Fatigue level changes with time in long-term Hodgkin and non-Hodgkin lymphoma survivors: a joint EORTC-LYSA cross-sectional study

BACKGROUND

Long-term lymphoma survivors often complain of persistent fatigue that remains unexplained. While largely reported in Hodgkin lymphoma (HL), long-term fatigue is poorly documented in non-Hodgkin lymphomas (NHL). Data collected in two cohort studies were used to illustrate the fatigue level changes with time in the two populations.

METHODS

Two cross-sectional studies were conducted in 2009-2010 (HL) and in 2015 (NHL) in survivors enrolled in European Organisation for Research and Treatment of Cancer (EORTC) Lymphoma Group and Lymphoma Study Association (LYSA) trials. The same protocol and questionnaires were used in both studies including the Multidimensional Fatigue Inventory (MFI) tool to assess fatigue and a checklist of health disorders. Multivariate linear regression models were used in the two populations separately to assess the influence of time since diagnosis and primary treatment, age, gender, education level, cohabitation status, obesity and health disorders on fatigue level changes. Fatigue level changes were compared to general population data.

RESULTS

Overall, data of 2023 HL and 1619 NHL survivors with fatigue assessment available (99 and 97% of cases, respectively) were analyzed. Crude levels of fatigue were similar in the two populations. Individuals who reported health disorders (61% of HL and 64% of NHL) displayed higher levels of fatigue than those who did not (P <  0.001). HL survivors showed increasing fatigue level with age while in NHL survivors mean fatigue level remained constant until age 70 and increased beyond. HL survivors showed fatigue changes with age higher than those of the general population with health disorders while NHL survivors were in between those of the general population with and without health disorders.

CONCLUSIONS

Among lymphoma survivors progressive increase of fatigue level with time since treatment completion is a distinctive feature of HL. Our data suggest that changes in fatigue level are unlikely to only depend on treatment complications and health disorders. Investigations should be undertaken to identify which factors including biologic mechanisms could explain why a substantial proportion of survivors develop high level of fatigue.

A Pilot Study Using a Multistaged Integrated Analysis of Gene Expression and Methylation to Evaluate Mechanisms for Evening Fatigue in Women Who Received Chemotherapy for Breast Cancer

CONTEXT

Fatigue is the most common symptom associated with cancer and its treatment. Investigation of molecular mechanisms associated with fatigue may identify new therapeutic targets.

OBJECTIVE

The objective of this pilot study was to evaluate the relationships between gene expression and methylation status and evening fatigue severity in women with breast cancer who received chemotherapy.

METHODS

Latent class analysis (LCA) was used to identify evening fatigue phenotypes. In this analysis, the lowest (i.e., moderate, n = 7) and highest (i.e., very high, n = 29) fatigue-severity classes identified using LCA were analyzed via two stages. First, a total of 32,609 transcripts from whole blood were evaluated for differences in expression levels between the classes. Next, 637 methylation sites located within the putative transcription factor binding sites for those genes demonstrating differential expression were evaluated for differential methylation state between the classes.

RESULTS

A total of 89 transcripts in 75 unique genes were differentially expressed between the moderate (the lowest fatigue-severity class identified) and very high evening fatigue classes. In addition, 23 differentially methylated probes and three differentially methylated regions were found between the moderate and very high evening fatigue classes.

CONCLUSIONS

Using a multistaged integrated analysis of gene expression and methylation, differential methylation was identified in the regulatory regions of genes associated with previously hypothesized mechanisms for fatigue, including inflammation, immune function, neurotransmission, circadian rhythm, skeletal muscle energy, carbohydrate metabolism, and renal function as well as core biological processes including gene transcription and the cell-cycle regulation.

The role of neuro-immune interactions in cancer-related fatigue: Biobehavioral risk factors and mechanisms

Fatigue is a common and distressing symptom in both patients with cancer and cancer survivors. There is substantial variation in the severity and persistence of cancer-related fatigue that may be driven by individual differences in host factors, including characteristics that predate the cancer experience as well as responses to cancer and its treatment. This review examines biobehavioral risk factors linked to fatigue and the mechanisms through which they influence fatigue across the cancer continuum, with a focus on neuro-immune processes. Among psychosocial risk factors, childhood adversity is a strong and consistent predictor of cancer-related fatigue; other risk factors include history of depression, catastrophizing, lack of physical activity, and sleep disturbance, with compelling preliminary evidence for loneliness and trait anxiety. Among biologic systems, initial work suggests that alterations in immune, neuroendocrine, and neural processes are associated with fatigue. The identification of key risk factors and underlying mechanisms is critical for the development and deployment of targeted interventions to reduce the burden of fatigue in the growing population of cancer survivors. Given the multidimensional nature of fatigue, interventions that influence multiple systems may be most effective.

Testing a biobehavioral model of fatigue before adjuvant therapy in women with breast cancer

BACKGROUND

Fatigue is one of the most common and disabling side effects of cancer and its treatment. Although research typically has focused on fatigue that occurs during and after treatment, patients may experience fatigue even before treatment onset. The current study was designed to identify biobehavioral risk factors associated with fatigue before adjuvant therapy in women with early-stage breast cancer.

METHODS

Patients with stage 0 to stage IIIA breast cancer (270 women) were recruited before the onset of adjuvant or neoadjuvant therapy with radiotherapy, chemotherapy, and/or endocrine therapy. Host factors that may influence fatigue were identified from an empirically based, biobehavioral model and assessed using self-report questionnaires, medical record review, and blood collection (for genetic data). Fatigue was assessed by questionnaire. Linear regression analyses were used to evaluate the association between host factors and dimensions of fatigue, with general fatigue as the primary dimension of interest.

RESULTS

Fatigue was elevated at the pretreatment assessment compared with published controls. Bivariate analyses identified demographic, cancer-related, and biobehavioral correlates of fatigue. In the multivariable model, predictors of general fatigue included younger age, lower educational level, lower cancer stage, and history of childhood maltreatment (all P values <.05), with the full model accounting for approximately 18.4% of the variance in fatigue. Secondary analyses identified common and specific predictors of emotional, mental, and physical dimensions of fatigue.

CONCLUSIONS

Among women who have not yet initiated treatment of breast cancer, demographic and psychosocial factors are associated with elevated fatigue and could be used to identify at-risk patients for early intervention.

Fatigue after breast cancer treatment: Biobehavioral predictors of fatigue trajectories

OBJECTIVE

Fatigue is a common side effect of cancer treatment, but there is considerable variability in fatigue severity and persistence among survivors. This study aimed to characterize longitudinal trajectories of fatigue after breast cancer treatment and to identify predictors of varying fatigue trajectories.

METHODS

Women (N = 191) from the Mind-Body Study completed assessments after primary treatment for early stage breast cancer and at regular follow-ups that occurred up to 6 years after treatment (M = 4.3 years). Growth mixture models were used to characterize fatigue trajectories, and demographic, medical, and biobehavioral risk factors were examined as predictors of trajectory group.

RESULTS

Five trajectories were identified, characterized as High, Recovery, Late, Low, and Very Low fatigue. The High and Recovery groups (40% of sample) evidenced elevated fatigue at posttreatment that declined in Recovery but persisted in the High group. In bivariate analyses, trajectory groups differed significantly on depressive symptoms, sleep disturbance, childhood adversity, body mass index, and the inflammatory marker soluble TNF receptor type II, which were higher in the High and/or Recovery groups. In multivariate models, depressive symptoms and childhood adversity distinguished High and Recovery from other groups. Rates of chemotherapy were higher in the Recovery than in the High or Late group, whereas rates of endocrine therapy were higher in the High than in the Recovery group.

CONCLUSIONS

There are distinct longitudinal trajectories of fatigue after breast cancer treatment. Psychological factors are strongly associated with adverse fatigue trajectories, and together with treatment exposures may increase risk for cancer-related fatigue. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Characteristics Associated With Physical Function Trajectories in Older Adults With Cancer During Chemotherapy

CONTEXT

Studies on physical function trajectories in older adults during chemotherapy remain limited.

OBJECTIVES

The objective of this study was to determine demographic, clinical, and symptom characteristics associated with initial levels as well as trajectories of physical function over two cycles of chemotherapy in adults aged ≥65 years with breast, gastrointestinal, gynecological, or lung cancer.

METHODS

Older adults with cancer (n = 363) who had received chemotherapy within the preceding four weeks were assessed six times over two cycles of chemotherapy using the Short Form-12 Physical Component Summary (PCS) score. Hierarchical linear modeling was used to evaluate for interindividual variability in initial levels and trajectories of PCS scores.

RESULTS

Mean age was 71.4 years (SD 5.5). Mean PCS score at enrollment was 40.5 (SD .45). On average, PCS scores decreased slightly (i.e., 0.21 points) at each subsequent assessment. Lower PCS scores at enrollment were associated with older age, greater comorbidity, being unemployed, lack of regular exercise, higher morning fatigue, lower evening energy, occurrence of pain, lower trait anxiety, and lower attentional function. Only higher morning fatigue and lower enrollment PCS scores were associated with decrements in physical function over time.

CONCLUSION

While several symptoms were associated with decrements in PCS scores at enrollment in older adults with cancer receiving chemotherapy, morning fatigue was the only symptom associated with decreases in physical function over time. Regular assessments of symptoms and implementation of evidence-based interventions should be considered to maintain physical function in older adults during chemotherapy.

Systematic review of genetic polymorphisms associated with psychoneurological symptoms in breast cancer survivors

PURPOSE

Psychoneurological (PN) symptoms, such as anxiety, cognitive impairment, depression, fatigue, sleep disturbances, and pain, are highly prevalent in breast cancer patients undergoing cancer treatment. Emerging evidence suggests that genetic polymorphisms may contribute to differential symptom susceptibility. We aimed to systematically review associations between genetic polymorphisms and PN symptoms during or after cancer treatment for early-stage breast cancer.

METHODS

Twenty-six eligible articles published until October 2017 were identified in PubMed, PsycINFO, Web of Science, and additional records. Information on study characteristics, genetic polymorphisms, and PN symptoms was extracted. Study quality was evaluated by the STrengthening the REporting of Genetic Association (STREGA) guideline. Genes included in the analysis were categorized by biological pathways based on the Reactome database.

RESULTS

A total of 54 single nucleotide polymorphisms and haplotypes that are significantly associated with PN symptoms were identified; half of them were associated with increased severity of PN symptoms, while the other half contributed to the decrease of PN symptoms. Pain has the known highest number of associated genetic polymorphisms reported, followed by fatigue, cognitive impairment, depressive symptoms, sleep disturbances, and anxiety. The majority of genetic polymorphisms were involved in immune system and neuronal system pathways. Most studies were unsuccessful in meeting the STREGA guideline, which requires transparent reporting of methods and results.

CONCLUSIONS

This review provides comprehensive evidence of genetic polymorphisms underlying PN symptoms, which may pave the way for the development of personalized therapeutics targeting these symptoms. More well-designed genome-wide association studies are required to validate and replicate these findings.

Neuroimmunology of Behavioral Comorbidities Associated With Cancer and Cancer Treatments

Behavioral comorbidities (depression, anxiety, fatigue, cognitive disturbances, and neuropathic pain) are prevalent in cancer patients and survivors. These mental and neurological health issues reduce quality-of-life, which is a significant societal concern given the increasing rates of long-term survival after various cancers. Hypothesized causes of behavioral comorbidities with cancer include tumor biology, stress associated with the cancer experience, and cancer treatments. A relatively recent leading mechanism by which these causes contribute to changes in neurobiology that underlie behavior is inflammation. Indeed, both basic and clinical research indicates that peripheral inflammation leads to central inflammation and behavioral changes in other illness contexts. Given the limitations of assessing neuroimmunology in clinical populations, this review primarily synthesizes evidence of neuroimmune and neuroinflammatory changes due to two components of cancer (tumor biology and cancer treatments) that are associated with altered affective-like or cognitive behaviors in rodents. Specifically, alterations in microglia, neuroinflammation, and immune trafficking to the brain are compiled in models of tumors, chemotherapy, and/or radiation. Evidence-based neuronal mechanisms by which these neuroimmune changes may lead to changes in behavior are proposed. Finally, converging evidence in clinical cancer populations is discussed.

Health status among long-term breast cancer survivors suffering from higher levels of fatigue: a cross-sectional study

PURPOSE

The aims of this study were to evaluate the health status of long-term breast cancer survivors (LTBCS) suffering from higher levels of fatigue, to highlight their needs, and to establish the key points of intervention support programs.

METHODS

A cross-sectional observational study was conducted at the Sport and Health Joint University Institute (iMUDS) between September 2016 and July 2017 with 80 LTBCS that were classified into non-fatigued (≤ 3.9) or fatigued (≥ 4) according to the Piper Fatigue Scale (PFS) total score. The instruments used were the European Organization for Research and Treatment of Cancer Core 30 and its breast cancer (BC) module, the Visual Analog Scale (VAS), the Brief Pain Inventory (BPI), the Scale for Mood Assessment (EVEA), the International Fitness Scale (IFIS), and the Charlson Comorbidity Index.

RESULTS

The analysis revealed that 41.2% of LTBCS were considered moderately fatigued and showed significantly higher levels for the categories of "nausea and vomiting" (P = .005), "pain," "dyspnea" and "insomnia" (P < .001), "appetite loss" (P = .002), "financial difficulties" (P = .010), "systemic therapy side effects" (P < .001), "breast symptoms" and "arm symptoms" (P = .002), and "upset by hair loss" (P = .016). In addition, LTBCS presented significantly higher levels of pain in the affected and non-affected arm, "sadness-depression." "anxiety," "anger/hostility" (All: P < .001), and lower general physical fitness (P < .001). The rest of the variables did not show significant differences.

CONCLUSION

LTBCS suffering from higher levels of fatigue had lower QoL, higher level of pain, worse mood state, and lower physical fitness.

Primer in Genetics and Genomics, Article 5-Further Defining the Concepts of Genotype and Phenotype and Exploring Genotype-Phenotype Associations

As nurses begin to incorporate genetic and genomic sciences into clinical practice, education, and research, it is essential that they have a working knowledge of the terms foundational to the science. The first article in this primer series provided brief definitions of the basic terms (e.g., genetics and genomics) and introduced the concept of phenotype during the discussion of Mendelian inheritance. These terms, however, are inconsistently used in publications and conversations, and the linkage between genotype and phenotype requires clarification. The goal of this fifth article in the series is to elucidate these terms, provide an overview of the research methods used to determine genotype-phenotype associations, and discuss their significance to nursing through examples from the current nursing literature.

Perceived fatigue and energy are independent unipolar states: Supporting evidence

Persistent fatigue is a common problem (∼20-45% of U.S. population), with higher prevalence and severity in people with medical conditions such as cancer, depression, fibromyalgia, heart failure, sleep apnea and multiple sclerosis. There are few FDA-approved treatments for fatigue and great disagreement on how to measure fatigue, with over 250 instruments used in research. Many instruments define fatigue as "a lack of energy", thus viewing energy and fatigue states as opposites on a single bipolar continuum. In this paper, we hypothesize that energy and fatigue are distinct perceptual states, should be measured using separate unipolar scales, have different mechanisms, and deficits should be treated using tailored therapies. Energy and fatigue independence has been found in both exploratory and confirmatory factor analysis studies. Experiments in various fields, including behavioral pharmacology and exercise science, often find changes in energy and not fatigue, or vice versa. If the hypothesis that energy and fatigue are independent is correct, there are likely different mechanisms that drive energy and fatigue changes. Energy could be increased by elevated dopamine and norepinephrine transmission and binding. Fatigue could be increased by elevated brain serotonin and inflammatory cytokines and reduced histamine binding. The hypothesis could be tested by an experiment that attempts to produce simultaneously high ratings of energy and fatigue (such as with two drugs using a randomized, double-blind, placebo-controlled design), which would offer strong evidence against the common viewpoint of a bipolar continuum. If the hypothesis is correct, prior literature using bipolar instruments will be limited, and research on the prevalence, mechanisms, and treatment of low energy and elevated fatigue as separate conditions will be needed. In the immediate future, measuring both energy and fatigue using unipolar measurement tools may improve our understanding of these states and improve therapeutic outcomes.

Association of genetic variants with fatigue in patients with malignant glioma

Background

Fatigue is a consistently reported, severe symptom among patients with gliomas throughout the disease trajectory. Genomic pathways associated with fatigue in glioma patients have yet to be identified.

Methods

Clinical factors (performance status, tumor details, age, gender) were collected by chart review on glioma patients with fatigue ("I have lack of energy" on Functional Assessment of Cancer Therapy-Brain), as well as available genotyping data. Candidate genes in clock and inflammatory pathways were identified from a literature review, of which 50 single nucleotide polymorphisms (SNPs) in 7 genes were available. Clinical factors and SNPs identified by univariate analyses were included in a multivariate model for moderate-severe fatigue.

Results

The study included 176 patients (median age = 47 years, 67% males). Moderate-severe fatigue was reported by 43%. Results from multivariate analysis revealed poor performance status and 2 SNPs were associated with fatigue severity. Moderate-severe fatigue was more common in patients with poor performance status (OR = 3.52, P < .01). For each additional copy of the minor allele in rs934945 (PER2) the odds of fatigue decreased (OR = 0.51, P < .05). For each additional copy of the minor allele in rs922270 (ARTNL2) the odds of fatigue increased (OR = 2.38, P < .01). Both of these genes are important in the circadian clock pathway, which has been implicated in diurnal preference, and duration and quality of sleep. No genes in the inflammatory pathway were associated with fatigue in the current study.

Conclusions

Identifying patients at highest risk for fatigue during treatment allows for improved clinical monitoring and enrichment of patient selection for clinical trials.

Distinct Evening Fatigue Profiles in Oncology Outpatients Receiving Chemotherapy

Background

Fatigue is the most common and debilitating symptom experienced by oncology patients during chemotherapy (CTX). Fatigue severity demonstrates a large amount of inter-individual and diurnal variability.

Purpose

Study purposes were to evaluate for subgroups of patients with distinct evening fatigue profiles and evaluate how these subgroups differed on demographic, clinical, and symptom characteristics.

Methods

Outpatients with breast, gastrointestinal, gynecological, or lung cancer (n=1332) completed questionnaires six times over two cycles of CTX. Lee Fatigue Scale (LFS) evaluated evening fatigue severity. Latent profile analysis was used to identify distinct evening fatigue profiles.

Results

Four distinct evening fatigue classes (i.e., Low (14.0%), Moderate (17.2%), High (36.0%), Very High (32.8%)) were identified. Compared to the Low class, patients in the Very High evening fatigue class were: younger, female, had childcare responsibilities, had more years of education, had a lower functional status, had a higher comorbidity burden, and were diagnosed with breast cancer. Patients in the Very High class reported higher levels of depressive symptoms, sleep disturbance, and evening fatigue at enrollment.

Conclusions

Findings provide new insights into modifiable risk factors for higher levels of evening fatigue. Clinicians can use this information to identify higher risk patients and plan appropriate interventions.

Mechanisms of Neurotoxic Symptoms as a Result of Breast Cancer and Its Treatment: Considerations on the Contribution of Stress, Inflammation, and Cellular Bioenergetics

PURPOSE OF REVIEW

Breast cancer and its treatment are associated with a range of neurotoxic symptoms, such as fatigue, cognitive impairment, and pain. Although these symptoms generally subside after treatment completion, they become chronic in a significant subset of patients. We here summarize recent findings on neuroinflammation, stress, and mitochondrial dysfunction as mechanistic pathways leading to neurotoxic symptom experience in breast cancer patients and survivors.

RECENT FINDINGS

Neuroinflammation related to stress or cancer treatment and stress resulting from diagnosis, treatment, or (cancer-related) worrying are important predictors of a neurotoxic symptom experience, both during and after treatment for breast cancer. Both inflammation and stress hormones, as well as cancer treatment, can induce mitochondrial dysfunction resulting in reduced cellular energy.

SUMMARY

We propose reduced cellular energy (mitochondrial dysfunction) induced by inflammation, oxygen radical production, and stress as a result of cancer and/or cancer treatment as a final mechanism underlying neurotoxic symptoms.

Associations Between Neurotransmitter Genes and Fatigue and Energy Levels in Women After Breast Cancer Surgery

CONTEXT

Fatigue is a common problem in oncology patients. Less is known about decrements in energy levels and the mechanisms that underlie both fatigue and energy.

OBJECTIVES

In patients with breast cancer, variations in neurotransmitter genes between lower and higher fatigue latent classes and between the higher and lower energy latent classes were evaluated.

METHODS

Patients completed assessments before and monthly for six months after surgery. Growth mixture modeling was used to identify distinct latent classes for fatigue severity and energy levels. Thirty candidate genes involved in various aspects of neurotransmission were evaluated.

RESULTS

Eleven single-nucleotide polymorphisms or haplotypes (i.e., ADRB2 rs1042718, BDNF rs6265, COMT rs9332377, CYP3A4 rs4646437, GALR1 rs949060, GCH1 rs3783642, NOS1 rs9658498, NOS1 rs2293052, NPY1R Haplotype A04, SLC6A2 rs17841327, and 5HTTLPR + rs25531 in SLC6A4) were associated with latent class membership for fatigue. Seven single-nucleotide polymorphisms or haplotypes (i.e., NOS1 rs471871, SLC6A1 rs2675163, SLC6A1 Haplotype D01, SLC6A2 rs36027, SLC6A3 rs37022, SLC6A4 rs2020942, and TAC1 rs2072100) were associated with latent class membership for energy. Three of 13 genes (i.e., NOS1, SLC6A2, and SLC6A4) were associated with latent class membership for both fatigue and energy.

CONCLUSIONS

Molecular findings support the hypothesis that fatigue and energy are distinct, yet related symptoms. Results suggest that a large number of neurotransmitters play a role in the development and maintenance of fatigue and energy levels in breast cancer patients.