Association of Fatigue Intensification with Cognitive Impairment during Radiation Therapy for Prostate Cancer.

PURPOSE: Cancer-related fatigue is a common complaint during cancer treatment and is often associated with cognitive impairment. This study examined cognitive deficits that were associated with fatigue symptoms during external-beam radiation therapy (EBRT) in men with localized prostate cancer. METHODS: A total of 36 participants were enrolled and followed up at baseline, 24 h, 7 days, 14 days after EBRT initiation, at midpoint, and at completion of EBRT. Fatigue was measured by self-report using the Functional Assessment of Cancer Therapy - Fatigue (FACT-F), and cognitive impairment by the Computer Assessment of Mild Cognitive Impairment (CAMCI®). RESULTS: Subjects with increased fatigue during EBRT reported a significant decline in cognitive function and had difficulties with CAMCI®'s route finding and item recall tasks during EBRT. Increased fatigue during EBRT was associated with perceived cognitive difficulties in executive function and recognition memory, but not with attention or verbal memory. CONCLUSIONS: Our results suggest that there might be specific cognitive domains that are associated with increased fatigue during EBRT. These findings will provide important information for targeting specific cognitive domains using pharmacotherapy or behavioral interventions. CAMCI® is a valuable tool for psycho social providers to detect subtle cognitive impairment in fatigued cancer patients in a clinical setting.

Exploratory Investigation of Early Biomarkers for Chronic Fatigue in Prostate Cancer Patients Following Radiation Therapy.

BACKGROUND: Fatigue is one of the most debilitating adverse effects of cancer therapy. Identifying biomarkers early during cancer therapy may help us understand the biologic underpinnings of the persistence of fatigue following therapy. OBJECTIVE: We aimed to identify early biomarkers of fatigue by examining correlations of levels of cytokines during external beam radiation therapy (EBRT) with persistence of fatigue 1 year following treatment completion in men with nonmetastatic prostate cancer (NM-PC). METHODS: A sample of 34 men with nonmetastatic prostate cancer scheduled to receive EBRT were followed up at baseline (T1), midpoint of EBRT (T2), and 1 year following EBRT (T3). Demographic and clinical data were obtained by chart review. The Functional Assessment of Cancer Therapy-Fatigue was administered to measure fatigue levels. Plasma cytokine levels were determined at T1 and T2 using the Bio-Rad Bio-Plex Cytokine Assay Kits. RESULTS: Significant correlations were observed between levels of interleukin 2 (IL-3), IL-8, IL-9, IL-10, IL-16, interferon γ-induced protein 10, interferon α2, interferon γ, and stromal cell-derived factor 1α at T2 with worsening of fatigue from T1 to T3. CONCLUSIONS: Immunological changes prior to chronic fatigue development may reflect the long-term response to radiation therapy-induced damage. IMPLICATIONS FOR PRACTICE: Early biomarkers for chronic fatigue related to cancer therapy will help advance our understanding of the etiology of this distressing symptom and will help nurses identify patients at risk of developing chronic fatigue after cancer treatment. This information will also aid in patient education, as well as symptom management.

Understanding the Association of Fatigue With Other Symptoms of Fibromyalgia: Development of a Cluster Model.

OBJECTIVE: To develop a symptoms cluster model that can describe factors of fibromyalgia syndrome (FMS) associated with fatigue severity as reported by the sample and to explore FMS clinical symptom subclusters based on varying symptom intensities. METHODS: FMS individuals (n = 120, 82% ages 31-60 years, 90% women, 59% white) diagnosed with the 1990 or 2010 American College of Rheumatology diagnostic criteria were enrolled. Participants completed multiple validated self-report questionnaires to measure fatigue, pain, depression, anxiety, pain catastrophizing, daytime sleepiness, cognitive function, and FMS-related polysymptomatic distress. Cluster analysis using SPSS 19.0 and structural equation modeling using AMOS 17.0 were used. RESULTS: Final structural equation modeling the symptoms cluster model showed good fit and revealed that FMS fatigue was associated with widespread pain, symptoms severity, pain intensity, pain interference, cognitive dysfunction, catastrophizing, anxiety, and depression (χ(2) = 121.72 (98df), P > 0.05, χ(2) /df = 1.242, comparative fit index = 0.982, root mean square error of approximation = 0.045). Two distinct clinical symptom subclusters emerged: subcluster 1 (78% of total subjects), defined by widespread pain, unrefreshed waking, and somatic symptoms, and subcluster 2 (22% of total subjects), defined by fatigue and cognitive dysfunction with pain being a less severe and less widespread occurrence. CONCLUSION: Overall, subcluster 1 had more intense symptoms than subcluster 2. FMS symptoms may be categorized into 2 clinical subclusters. These findings have implications for an illness whose diagnosis and management are symptom dependent. A longitudinal study capturing the variability in the symptom experience of FMS subjects is warranted.

A murine model of peripheral irradiation-induced fatigue.

PURPOSE: Fatigue is the most ubiquitous side effect of cancer treatment, but its etiology remains elusive. Further investigations into cancer-related fatigue pathobiology necessitate the expanded use of animal models. This study describes the development of a murine model of radiation-induced fatigue. METHODS: Voluntary wheel running activity measured fatigue in 5-8 week-old, male C57BL/6 mice before and after γ irradiation totaling 2400cGy (3 consecutive days×800cGy daily fractionated doses) to the lower abdominal areas. Three trials confirmed fatigue behavior at this dose. Anhedonia, body weight, and hemoglobin were also measured. Gastrointestinal, skeletal muscle, and bone marrow tissue samples were evaluated for signs of damage. RESULTS: In two validation trials, irradiated mice (trial 1, n=8; trial 2, n=8) covered less cumulative distance in kilometers post-irradiation (trial 1, mean=115.3±12.3; trial 2, mean=113.6±21.8) than sham controls (trial 1, n=5, mean=126.3±5.7, p=0.05; trial 2, n=8, mean=140.9±25.4, p=0.02). Decreased mean daily running distance and speed were observed during the last four hours of the dark cycle in irradiated mice compared to controls for two weeks post-irradiation. There were no differences in saccharin preference or hemoglobin levels between groups, no effect of changes in body weight or hemoglobin on wheel running distance, additionally, histology showed no damage to muscle, bone marrow, or gastrointestinal integrity, with the latter confirmed by ELISA. CONCLUSION: We characterized a novel mouse model of fatigue caused by peripheral radiation and not associated with anemia, weight changes, or anhedonia. This model provides opportunities for detailed study of the mechanisms of radiation-induced fatigue.

Comparing Genomic Profiles of Women With and Without Fibromyalgia.

BACKGROUND: Fibromyalgia syndrome (FMS), a chronic musculoskeletal condition characterized by diffuse pain, fatigue, sleep impairment, and cognitive dysfunction, is associated with significant functional disability. Its underlying biological mechanisms are unknown. This study investigated differentially expressed genes between women with FMS and healthy volunteers. METHODS: Women who met the 1990 or 2010 American College of Rheumatology fibromyalgia criteria were compared to age- and race-matched pain-free healthy women. Peripheral blood samples were collected, and a full genome microarray gene expression analysis was performed. One-way analysis of variance was used to identify differentially expressed genes using the filtering criterion of 1% false discovery rate. Analysis of canonical pathways associated with these genes was performed. Confirmatory quantitative real-time polymerase chain reaction and enzyme-linked immunosorbent assay verified microarray results. Independent t-tests compared gene and protein expression between groups. RESULT: Participants were 54 women with FMS and 25 controls. Expression arrays from a subset of women with FMS (n = 29) and controls (n = 20) showed upregulation of 12 genes (>1.8-fold change, p < .05) in the FMS sample. Differentially expressed genes were related to B-cell development, primary immunodeficiency signaling, and mitotic roles of polo-like kinase. CENPK and HSP90AA1 were the most differentially expressed genes (p < .01). CONCLUSION: Activity of interrelated pathways related to immune response, and homeostasis appears to be relevant to the experience of FMS. Replication and exploration of the relationship between gene expression and symptom severity will help determine clinical relevance of these findings.