Assessment of fatigue in cancer and non-cancer patients and in healthy individuals.

Fatigue is a very complex phenomenon. It has been described as a major distressing symptom in cancer patients. It is a multidimensional experience that focuses not only on biochemical or pathophysiological causes, but also involves psychological and behavioural aspects. Until today, measurement of fatigue has been a neglected topic in medicine and nursing and a nihilistic attitude still prevails. The lack of valid, reliable tools of measurement is one of the problems inhibiting further research. Only recently has quality-of-life research begun to acknowledge this phenomenon and include fatigue in assessment. In this study, fatigue was measured and explored in cancer patients non-cancer patients and in healthy individuals. A clear distinction evolved between "healthy" fatigue in healthy individuals and "unhealthy" fatigue in cancer patients, where the impact of fatigue was far more negative. Characteristic fatigue profiles underlined these findings. The new visual-analogue fatigue scale, to measure fatigue four times daily, proved to be very useful. Further research is needed to develop therapeutic strategies and to support the patients who have to cope with this distressing symptom.