The cultural constructs of cancer-related fatigue among American Indian cancer survivors

This aim of this systematic review was to determine the prevalence and pattern of cancer-related fatigue (CRF), and identify factors associated with its development. Relevant literature was identified through an electronic database search using specified keywords. Included studies investigated CRF in adult cancer patients using a multidimensional fatigue measure. The methodological quality was assessed using six published standards. CRF is apparent both during and after anti-cancer therapy, however, the prevalence of CRF varied between studies. The variables associated with the development and persistence of CRF remain to be identified. Inconsistencies were evident in the pattern of CRF and its associated factors. This is likely to have arisen from the inherent difficulties in the measurement of a subjective sensation, further complicated by the myriad of outcome measures used. More methodologically sound research; assessing CRF from the commencement of therapy, considering all pertinent variables is needed.

To determine the occurrence of cancer-related fatigue, the methods used to assess it, and the efficacy of the available treatments, we performed literature searches that identified English-language publications on these topics. Twenty-seven studies were identified in which the quantitative estimation of the occurrence of cancer-related fatigue was an end point. Fifty-six were judged to be relevant to the assessment of fatigue, and 10 randomized controlled clinical trials of treatments of cancer-related fatigue were retrieved. The occurrence of cancer-related fatigue was found to range from 4% to 91%, depending on the population studied and the methods of assessment. Few population-based studies and no longitudinal studies of cancer-related fatigue have been performed. The methods of fatigue assessment were highly variable. Exercise programs show promise to prevent or treat fatigue in some subsets of cancer patients, and the use of epoetin alfa for correction of anemia has been shown to ameliorate fatigue. The number of subjects in the treatment trials was small and their methodologic quality was inconsistent.

Although fatigue is one of the most common complaints of patients with cancer, it went unrecognized or overlooked for many years, until clinicians achieved better control over the more acute symptoms of nausea, emesis, and pain. A number of treatment-related and disease-related factors may contribute to the development of fatigue, but its physiologic basis remains poorly understood, and many proposed interventions have not been studied systematically. The lack of a standard of care for the assessment or treatment of fatigue in patients with cancer has limited research in this field. A critical appraisal of these issues is presented in this review. The published literature was reviewed for definition, prevalence, causes, and means of managing cancer-related fatigue (CRF). Fatigue was reportedly present at the time of diagnosis in approximately 50-75% of cancer patients. The prevalence of CRF increased to 80-96% in patients undergoing chemotherapy and to 60-93% in patients receiving radiotherapy. Two tested interventions that showed consistent effects to alleviate CRF were treatment of cancer-related anemia with erythropoietin agents (recombinant human erythropoietin and darbepotin alpha) and aerobic exercise. Several lines of research are needed to bridge the specific gaps in the current knowledge of CRF. These involve the pathophysiology of the symptom, the validation of diagnostic criteria, and specific therapeutic interventions. Current practice guidelines are based on a combination of research and expert clinical judgment and should be used to guide care with the expectation that they will evolve to incorporate the results of studies currently underway. Copyright 2003 American Cancer Society.