[Fatigue--when cancer patients are consistently without drive and energy. Determine the etiology!]

Fatigue in tumor patients is caused both by the tumor and/or its treatment, and is accompanied by loss of drive, lack of energy, depressive mood and loss of vitality; it is unresponsive to rest and sleep. A differentiation is made between mental fatigue, drive fatigue and psychological fatigue. In particular cytokines produced by the cancer cells, but also by the immune system, play a pathophysiological role. Such cytokines as interferon gamma and interleukin are also involved in the development of cachexia in tumor patients, and may also lead to changes in sleep pattern. An additional factor contributing to the loss of performance and exhaustion in cancer patients is the frequently deficient oxygen supply to the muscles, as also anemia, which is often seen in advanced tumor disease. Mental fatigue is also closely associated with depressive mood as well as the noxious influences of cytostatic agents, steroids and painkillers on the CNS. The causes of fatigue should always be investigated before appropriate causal treatment can be instituted.