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.

Longitudinal study of inflammatory, behavioral, clinical, and psychosocial risk factors for chemotherapy-induced peripheral neuropathy.

PURPOSE: Chemotherapy-induced peripheral neuropathy (CIPN) is a common dose-limiting side effect of taxane and platinum chemotherapy for breast cancer. Clinicians cannot accurately predict CIPN severity partly because its pathophysiology is poorly understood. Although inflammation may play a role in CIPN, there are limited human studies. Here, we identified the strongest predictors of CIPN using variables measured before taxane- or platinum-based chemotherapy, including serum inflammatory markers. METHODS: 116 sedentary women with breast cancer (mean age 55 years) rated (1) numbness and tingling and (2) hot/coldness in hands/feet on 0-10 scales before and after 6 weeks of taxane- or platinum-based chemotherapy. A sub-study was added to collect cytokine data in the final 55 patients. We examined all linear models to predict CIPN severity at 6 weeks using pre-chemotherapy assessments of inflammatory, behavioral, clinical, and psychosocial factors. The final model was selected via goodness of fit. RESULTS: The strongest pre-chemotherapy predictors of numbness and tingling were worse fatigue/anxiety/depression (explaining 27% of variance), older age (9%), and baseline neuropathy (5%). The strongest predictors of hot/coldness in hands/feet were worse baseline neuropathy (11%) and fatigue/anxiety/depression (6%). Inflammation was a risk for CIPN, per more pro-inflammatory IFN-γ (12%) and IL-1ß (6%) and less anti-inflammatory IL-10 (6%) predicting numbness/tingling and more IFN-γ (17%) and less IL-10 (9%) predicting hot/coldness in hands/feet. CONCLUSIONS: The strongest pre-chemotherapy predictors of CIPN included worse fatigue/anxiety/depression and baseline neuropathy. A pro-inflammatory state also predicted CIPN. Because this is an exploratory study, these results suggest specific outcomes (e.g., IL-1ß) and effect size estimates for designing replication and extension studies. CLINICAL TRIAL REGISTRATION: NCT00924651.

Effects of High-Dose Vitamin D Supplementation on Phase Angle and Physical Function in Patients with Prostate Cancer on ADT.

PURPOSE: Androgen deprivation therapy (ADT) is commonly used to treat patients with advanced prostate cancer but is associated with functional decline. Bioelectrical impedance analysis (BIA)-derived phase angle may reflect frailty and functional decline in cancer patients. High-dose vitamin D supplementation may improve phase angle values and physical function. METHODS: We conducted an exploratory analysis from a phase II randomized controlled trial investigating the efficacy of high-dose vitamin D supplementation in prostate cancer patients (age ≥ 60 yrs). Fifty-nine patients were randomized to high-dose vitamin D (600 IU/day plus 50,000 IU/week) or low-dose: RDA for vitamin D (600 IU/day plus placebo weekly) for 24 weeks. Phase angle was measured by BIA. Physical function measures included handgrip strength, 6-minute walk test, Short Performance Physical Battery and leg extension. All testing was completed at baseline, week 12 and week 24. RESULTS: Phase angle values were wider over the entire study in the high-dose vitamin D arm indicating healthier muscle cells. The low-dose vitamin D arm had phase angle values consistent with frailty cutoffs in older men (<5.7°). CONCLUSION: Patients in the high-dose vitamin D arm experienced wider phase angle values over the course of the study which may indicate less frailty. ClinicalTrials.gov ID: NCT02064946.

Excess Body Weight and Cancer-Related Fatigue, Systemic Inflammation, and Serum Lipids in Breast Cancer Survivors.

BACKGROUND: Cancer-related fatigue (CRF) is a common side effect impacting breast cancer survivors. Research points to a relationship between obesity and CRF in breast cancer survivors related to elevated systemic inflammation and metabolic alterations. METHODS: This cross-sectional study examined the relationship of obesity to CRF, inflammatory markers and serum lipids through a secondary analysis of a nationwide randomized controlled trial. Breast cancer survivors with CRF were categorized based on BMI category. Symptoms of CRF, inflammatory markers and serum fatty acids were assessed among groups. RESULTS: There were 105 breast cancer survivors in the analysis. BMI was positively associated with CRF based on MFSI General (p = 0.020; 95% C.I. 0.024, 0.273) and MFSI Physical (p = 0.013; 95% C.I. 0.035, 0.298) subscales. TNF-α (p = 0.007; 95% C.I. 0.007, 0.044), and IL-6 (p = 0.020; 95% C.I. 0.006, 0.073) were elevated in the obese. Monounsaturated fatty acid levels (p = 0.047; 95% C.I. 0.000, 0.053) and the omega-6 to omega-3 fatty acid ratio were associated with obesity (p = 0.047; 95% C.I. 0.002, 0.322). CONCLUSIONS: Obese breast cancer survivors had greater levels of CRF, inflammatory markers and certain fatty acids. Inflammatory markers and fatty acids were not found to have any mediating or positive association with CRF variables in this analysis. NCT02352779.

Association Between Pretreatment Sleep Disturbance and Radiation Therapy-Induced Pain in 573 Women With Breast Cancer.

CONTEXT: Pain can be a debilitating side effect of radiation therapy (RT). Data from the general population have shown that sleep disturbance can influence pain incidence and severity; however, less is known about this relationship in patients with breast cancer receiving RT. OBJECTIVES: This secondary analysis examined the association of pretreatment moderate/severe levels of sleep disturbance with subsequent RT-induced pain after adjusting for pre-RT pain. METHODS: We report on 573 female patients with breast cancer undergoing RT from a previously completed Phase II clinical trial for radiation dermatitis. Sleep disturbance, total pain, and pain subdomains-sensory pain, affective pain, and perceived pain intensity were assessed at pre-RT and post-RT. At pre-RT, patients were dichotomized into two groups: those with moderate/severe sleep disturbance (N = 85) vs. those with no/mild sleep disturbance (control; N = 488). RESULTS: At pre-RT, women with moderate/severe sleep disturbance were younger, less likely to be married, more likely to have had mastectomy and chemotherapy, and more likely to have depression/anxiety disorder and fatigue than the control group (all Ps < 0.05). Generalized estimating equations model, after controlling for pre-RT pain and other covariates (e.g., trial treatment condition and covariates that were significantly correlated with post-RT pain), showed that women with moderate/severe sleep disturbance at pre-RT vs. control group had significantly higher mean post-RT total pain as well as sensory, affective, and perceived pain (effect size = 0.62, 0.60, 0.69, and 0.52, respectively; all Ps < 0.05). CONCLUSION: These findings suggest that moderate/severe disturbed sleep before RT is associated with increased pain from pre-to-post-RT in patients with breast cancer.

Longitudinal assessment of the impact of higher body mass index on cancer-related fatigue in patients with breast cancer receiving chemotherapy.

PURPOSE: To assess the impact of obesity on cancer-related fatigue (CRF) in patients with breast cancer, through a secondary analysis of a large, longitudinal, nationwide study of breast cancer patients beginning chemotherapy. METHODS: All patients (N = 565; aged 53 ± 10.6) with breast cancer completed the multidimensional fatigue symptom inventory and the symptom inventory to measure CRF symptoms at baseline, post-chemotherapy, and 6 months post-chemotherapy. Height and weight at baseline were used to categorize subjects based on body mass index (BMI): obese (≥ 30.0 kg/m2; n = 294), overweight (25.0-29.9 kg/m2; n = 146), and normal weight (18.5-24.9 kg/m2; n = 125). Multivariate regression models evaluated the relationship of obesity level to CRF over time, controlling for age, menopausal status, race, Karnofsky Performance Status, cancer stage, radiation, and exercise status. RESULTS: At baseline, the obese had significantly higher CRF symptoms than the normal weight subjects for both the Multidimensional fatigue symptom inventory (MFSI) total (obese = 11.2 vs normal weight = 6.3; p = 0.03) and Symptom Inventory (SI) (obese = 3.5 vs normal weight = 2.9; p = 0.03). Significantly higher SI fatigue scores persisted at post-chemotherapy for the obese (obese = 5.0 vs normal weight = 4.4; p = 0.02). At 6 months post-chemotherapy, the obese patients still had significantly higher SI fatigue scores (obese = 3.5 vs normal weight = 3.0; p = 0.05). CONCLUSION: Obese patients suffered greater CRF from pre-chemotherapy through 6 months post-chemotherapy. Recommendations for weight loss or weight maintenance may impact CRF levels in obese breast cancer patients before and after chemotherapy.

Influence of Yoga on Cancer-Related Fatigue and on Mediational Relationships Between Changes in Sleep and Cancer-Related Fatigue: A Nationwide, Multicenter Randomized Controlled Trial of Yoga in Cancer Survivors.

BACKGROUND: Cancer-related fatigue (CRF) often co-occurs with sleep disturbance and is one of the most pervasive toxicities resulting from cancer and its treatment. We and other investigators have previously reported that yoga therapy can improve sleep quality in cancer patients and survivors. No nationwide multicenter phase III randomized controlled trial (RCT) has investigated whether yoga therapy improves CRF or whether improvements in sleep mediate the effect of yoga on CRF. We examined the effect of a standardized, 4-week, yoga therapy program (Yoga for Cancer Survivors [YOCAS]) on CRF and whether YOCAS-induced changes in sleep mediated changes in CRF among survivors. STUDY DESIGN AND METHODS: Four hundred ten cancer survivors were recruited to a nationwide multicenter phase III RCT comparing the effect of YOCAS to standard survivorship care on CRF and examining the mediating effects of changes in sleep, stemming from yoga, on changes in CRF. CRF was assessed by the Multidimensional Fatigue Symptom Inventory. Sleep was assessed via the Pittsburgh Sleep Quality Index. Between- and within-group intervention effects on CRF were assessed by analysis of covariance and 2-tailed t test, respectively. Path analysis was used to evaluate mediation. RESULTS: YOCAS participants demonstrated significantly greater improvements in CRF compared with participants in standard survivorship care at post-intervention ( P < .01). Improvements in overall sleep quality and reductions in daytime dysfunction (eg, excessive napping) resulting from yoga significantly mediated the effect of yoga on CRF (22% and 37%, respectively, both P < .01). CONCLUSIONS: YOCAS is effective for treating CRF among cancer survivors; 22% to 37% of the improvements in CRF from yoga therapy result from improvements in sleep quality and daytime dysfunction. Oncologists should consider prescribing yoga to cancer survivors for treating CRF and sleep disturbance.

Multicenter Randomized Controlled Trial of Omega-3 Fatty Acids Versus Omega-6 Fatty Acids for the Control of Cancer-Related Fatigue Among Breast Cancer Survivors.

BACKGROUND: Cancer-related fatigue (CRF) is a common side effect of adjuvant therapy and becomes a chronic problem for approximately one-third of survivors. Omega-3 polyunsaturated fatty acids (O3-PUFA) demonstrated preliminary antifatigue effects in previous research, but have not been investigated in fatigued cancer survivors. METHODS: Breast cancer survivors 4-36 months posttreatment with a CRF score of 4 or more of 10 using the symptom inventory (SI) were randomly assigned to O3-PUFA (fish oil, 6 g/d), omega-6 PUFA (O6-PUFA; soybean oil, 6 g/d), or a low-dose combination of O3-/O6-PUFA (3 g/d O3-PUFA and O6-PUFA) for 6 weeks. CRF was assessed by the SI (screening question), the Brief Fatigue Inventory, and the Multidimensional Fatigue Symptom Index. Protein and mRNA levels of inflammatory and antioxidant biomarkers, along with fatty acid and lipid levels, were assessed at baseline and week 6. Statistical tests were two-sided. RESULTS: A total of 108 breast cancer survivors consented; 97 subjects were randomly assigned and 81 completed the trial. The SI CRF score decreased by 2.51 points at week 6 with O6-PUFA and by 0.93 points with O3-PUFA, with statistically significant between-group difference (effect size = -0.86, P < .01). Similar changes were observed for the Brief Fatigue Inventory and Multidimensional Fatigue Symptom Index but were not statistically significant. Stratified analyses showed the largest benefit was observed in those with severe baseline CRF (≥7). Compared with O3-PUFA, O6-PUFA supplementation statistically significantly decreased proinflammatory markers in the TNF-α signaling pathway. CONCLUSION: Contrary to our original hypothesis, O6-PUFA statistically significantly reduced CRF compared with O3-PUFA. Further research is needed to confirm these findings and to elucidate mechanisms of action.

Nutritional Interventions for Treating Cancer-Related Fatigue: A Qualitative Review.

Cancer-related fatigue (CRF) is a debilitating syndrome that persists for many cancer survivors for years after treatment. Symptoms include early and persistent fatigue, functional decline, depression, and cognitive difficulties. Inflammation, assessed using pro-inflammatory biomarkers, is increased in cancer survivors with fatigue and treatments for fatigue are often aimed at reducing inflammation. Additionally, cancer and its treatment lead to nutritional complications, changes in body composition, and nutritional deficiencies that potentially weaken the cancer survivor and impact CRF. We conducted a qualitative review of clinical trials that assessed nutritional interventions for preventing and treating CRF. Further studies were examined that used nutritional interventions to address inflammation and fatigue, due to the dearth of nutrition research directly related to CRF. Dietary intake prior to, during, and after cancer treatment appears to affect fatigue levels. Increased protein intake may help preserve lean mass and body composition. Dietary patterns that reduce inflammation, such as the Mediterranean diet and other plant-based diets, appear tolerable to cancer survivors and may reduce fatigue. Supplementation with ginseng, ginger, or probiotics may improve cancer survivors' energy levels. Nutritional interventions, alone or in combination with other interventions should be considered as therapy for fatigue in cancer survivors.