The pathogenesis of cancer related fatigue: Could increased activity of pro-inflammatory cytokines be the common denominator?

Cancer related fatigue (CRF), defined as a persistent subjective sense of tiredness related to cancer or cancer treatment that interferes with daily functioning, is highly prevalent and probably the most underestimated and insufficiently treated complication in cancer patients. Therefore, unravelling the pathogenesis of CRF is of great importance allowing the identification of novel therapeutic targets. It is generally believed that the pathogenesis is multicausal, explaining why most therapeutic interventions directed towards only one potential causative factor are unsuccessful. In this regard, it is of interest that increased activity of pro-inflammatory cytokines might be a common denominator causing CRF. Detailed insight in the central role of increased activity of pro-inflammatory cytokines in CRF will hopefully offer an effective approach in the treatment of CRF by affecting a broad array of proposed causative factors such as anaemia, disturbances of the hypothalamic–pituitary–adrenal axis and altered brain serotonin metabolism.