[Fatigue and quality of life in cancer patients]

Fatigue is the most frequent adverse event encountered in cancer patients and often underestimated by oncologists. This fatigue results in a deterioration of the quality of life physically, psychologically and socio-professionally. We have to distinguish various degrees of fatigue and identify "acute" fatigue from "chronic" fatigue. The acute fatigue appears normal after a physical or psychological effort and requires less than a week of rest to recover; the impact on quality of life is thus minimal. Chronic fatigue is more insidious; the causes are multiple. The patient feels that this fatigue is abnormal and disproportionate. It last several weeks and has a severe impact on the quality of life. Somatic mechanisms of fatigue related to the tumour and/or treatment are: vitaminic or proteic deficiencies due to malnutrition, accumulation of toxic metabolites, infections and septicemia, the abuse of sleeping tablets or antalgics, insomnias, immobilisation, organic insufficiencies or ionic disturbances. Anemia--observed in more than 50% of the cancerous patients--deserves a particular attention. The causes of this anemia are also multiple. It is obvious that anemia interferes with quality of life of the patient, decreases his physical performances and leads to a lack of motivation or energy. Patients with an hemoglobin level higher than 12 g/dl describe significantly less complaints and a higher physical and functional well being. To better assess the treatment of fatigue, it is important to first evaluate if the cause is organic, psychologic or mixed. Among the somatic causes, nutritious deficiencies, pain and anemia, ... all these complications can be treated with appropriate medications. This fatigue is often recognized by the patient as a progression of the tumour or as a treatment failure. Therefore, it is important to inform the patients of the possibility of that adverse event so that it does not generate additional stress and anxiety during the treatment.