Assessment of fatigue in cancer patients

Increased recognition of the problem of fatigue in cancer patients can be attributed, in part, to the development of measures that have provided researchers with the tools necessary for quantifying and characterizing fatigue and exploring its etiology and treatment. Although a consensus regarding the definition of fatigue is lacking, there is general agreement that it is a subjective and multidimensional phenomenon whose assessment requires the use of self-report methods. Consistent with this view, several multidimensional measures of fatigue have been developed and validated for use with cancer patients. These measures differ considerably in their format and content and, as with the definition of fatigue, there is no consensus at the present time regarding the dimensional structure of fatigue. In addition to measuring fatigue on a continuum along one or more dimensions, it may also be possible to assess a clinical syndrome of cancer-related fatigue. Criteria for assessing fatigue in this manner have been proposed and are currently undergoing evaluation. Despite the progress that has been made, there are several important unresolved issues in the assessment of fatigue in cancer patients. These include how to distinguish fatigue from depression, how to use self-reports of fatigue in clinical decision-making, how to capture temporal changes in fatigue, and how best to address the continuing lack of consensus regarding the conceptualization and measurement of fatigue.