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-1β, 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.