[Functional iron deficiency, inflammation and fatigue after radiotherapy]

Radiation therapy is associated with a fatigue in the majority of patients with a relative variability according to the type of the tumour, comorbidities, associated treatments and the extent of the irradiation. Its origin is multifactorial. One explanation described is that fatigue could be related to the inflammation caused by irradiation exposure. One of the suspected mechanisms is a functional iron deficiency following pro-inflammatory cytokines synthesis, particularly the interleukins 1 and 6. This phenomenon is accompanied by a reduced availability of iron, while iron reserves are normal or increased. Thus, iron inaccessibility induces lower coefficient of transferrin saturation, which can lead to a non-regenerative normocytic or microcytic anaemia. The availability of iron is controlled by hepcidin that is synthesized in the liver as a response to radiation-induced inflammatory. The presence of hepcidin blocks iron absorption in the intestine and decreases its recycling from senescent red blood cells. A direct relationship between elevated levels of hepcidin, inflammation markers and radiation-induced side effects have been reported. The aim of the article is to review the literature related to fatigue in radiotherapy and understand the mechanisms involved or worsening its occurrence to consider better care and improve patients' quality.