Cancer-Related Fatigue and Circulating Biomarkers in Breast Cancer Survivors.

PURPOSE: Cancer-related fatigue (CRF) is the most common and disruptive symptom experienced by cancer survivors and because of its frequency and severity is especially worrisome in breast cancer survivors (BCS). Despite a great deal of research, the mechanisms underlying CRF have not been determined. The present study aims to describe associations between CRF in BCS and different blood biomarkers. METHODS: A descriptive and cross-sectional study was conducted. A set of biomarkers assessing inflammation were measured in BCS: C-reactive protein (CRP), neutrophil-lymphocyte ratio (NLR), IL-1ß, IL-6, IL-8, IL-10, tumor necrosis factor (TNF); HPA axis dysfunction (cortisol), autonomic dysfunction (noradrenaline); oxidative stress (8-OH deoxyguanosine); insulin resistance markers (insulin, IGF-I, IGFBP3) and sexual hormones (estrogens, progesterone, testosterone). RESULTS: NLR (p = .00) and cortisol (p = .02) were positive and negatively associated with CRF, respectively. The rest of the blood markers were not associated with CRF. CONCLUSION: Our results increase the evidence on pathophysiological mechanisms driving CRF in BCS. However, longitudinal studies are needed to explore the role of these factors as potential causal mechanisms.

Prevalence and correlates of cancer-related fatigue in breast cancer survivors.

PURPOSE: To identify potential correlates of cancer-related fatigue (CRF) after curative breast cancer (BC) treatment. The hypothesis was that fatigue would be more severe among women treated with cardiotoxic drugs, with poor physical condition and those who exercised less. METHODS: Observational cross-sectional design. Fatigue was evaluated through PERFORM Questionnaire (multi-item, multi-dimensional). Patient-reported assessments and objective information regarding clinical data, physical activity (PA) and physical condition were analysed as potential correlates of CRF. RESULTS: One hundred eighty women who remained free of disease were recruited. The prevalence of fatigue interfering with quality of life was 43%. Weight, resting and recovery heart rate were positively associated with fatigue. Age and time from diagnosis were negatively associated. Previous therapies, objectively assessed weekly PA, cardiorespiratory condition, muscular strength and adherence to Mediterranean diet were not associated with CRF. CONCLUSIONS: CRF is a prevalent problem after BC treatment. Objectively assessed PA, cardiorespiratory fitness and muscular strength did not predict CRF. The association of heart rate and fatigue deserves a further insight. Future research should include longitudinal studies and determination of biomarkers. IMPLICATIONS FOR CANCER SURVIVORS: BC survivors, especially younger and overweight women, should be informed about fatigue as a potential persistent symptom through all stages of the cancer trajectory and into survivorship. They also should be routinely screened for CRF.

Cancer-related Fatigue in Breast Cancer Survivors: A Review.

Fatigue has been the most distressing and frequent symptom in breast cancer (BC) survivors after treatment. Although fatigue can occur in other cancer survivors, women with a history of BC might share some distinctive features. The present study aimed to recapitulate the knowledge about risk factors and correlates of cancer-related fatigue (CRF) in BC survivors after oncologic therapy. An electronic data search was conducted in PubMed using the terms "fatigue," "breast," "cancer," and "survivors." Records were included if they were original articles, available in English, had used a quantitative scale, had > 100 participants, and had excluded women with BC relapse. BC survivors were required to have finished their treatments ≥ 2 months before, except for hormonal therapy. The physiopathology and other interventions were considered beyond the scope of our review. The correlates were subsequently classified into 7 main categories: (1) sociodemographic data, (2) physical variables, (3) tumor- and treatment-related variables, (4) comorbidities, (5) other symptoms, (6) psychological issues, and (7) lifestyle factors. Fatigue was consistently greater in younger, obese, and diabetic women. Women reporting fatigue often communicated symptoms such as pain, depression, insomnia, and cognitive dysfunction. Coping strategies such as catastrophizing could play an important role in the persistence of fatigue. However, tumor characteristics, previous treatments received, and physical activity were not consistently reported. CRF was a strong predictor of the quality of life of BC survivors after treatment. In conclusion, we found CRF was a frequent and serious symptom that severely affects the quality of life of BC survivors after treatment. Health practitioners require more awareness and information about CRF.