Psychological and immunological characteristics of fatigued women undergoing radiotherapy for early-stage breast cancer

The amelioration of fatigue in radiotherapy patients is limited by an equivocal aetiology and uncertainty regarding who is likely to experience significant fatigue. The research objective was to characterise fatigue in women undergoing radiotherapy for breast cancer, in order to evaluate associations with elevations in anxiety, depression and a marker of systemic inflammation. Participants comprised 100 women, diagnosed with stages 0-IIA breast cancer and prescribed with 40 Gy in 15 fractions over 3 weeks. Fatigue was assessed at baseline between 10 and 22 days before radiotherapy, after 10 and 15 fractions of radiotherapy and 4 weeks after the completion of radiotherapy, using the Functional Assessment of Chronic Illness Therapy Fatigue Subscale. Psychological status was self-reported using the Hospital Anxiety and Depression Scale. Sera concentrations of interleukin-6-soluble receptor were established via enzyme-linked immunosorbent assay. The contributions of pretreatment factors to fatigue were analysed using multivariable regression. Thirty-eight percent of participants experienced significant fatigue during radiotherapy, with the remainder little are affected. After controlling for baseline fatigue, anxiety before treatment was the strongest unique predictor of subsequent fatigue. During radiotherapy, interleukin-6-soluble receptor was significantly elevated in the fatigued group compared to the non-fatigued group (p = 0.01). This association was not mediated by depression. The data are consistent with the concept that psychological distress prior to radiotherapy relates to a distinct immunological and behavioural response during radiotherapy. Patients reporting elevated anxiety should benefit from interventions that appropriately address the underlying psychological distress and have the potential to ameliorate disabling treatment-related fatigue.