Evidenced-based report on the occurrence of fatigue in long-term cancer survivors.
Although some cancer survivors report persistent fatigue years after treatment, little is known about the prevalence of the symptom in this population as compared with the general population. This article examines current evidence for the occurrence of fatigue in long-term cancer survivors by reviewing published population-based studies that incorporated controls from the general population. Using the search criteria "fatigue AND cancer survivors" in PubMed, the authors identified 16 articles (based on 15 cross-sectional datasets) comparing fatigue severities in survivors of adult cancers with those in the general population. When data allowed, Hedges' g effect size calculations were generated. A total of 8096 cancer survivors were examined across datasets. Cancer survivor sample sizes ranged from 15 to 1933 per dataset. Most datasets focused on either breast cancer (7) or Hodgkin's disease survivors (6). Four studies did not clearly exclude patients undergoing active treatment. Nine articles (based on 8 datasets) showed statistically significant (P < .05) differences among groups; 4 articles showed negative results; and 3 showed both positive and negative results depending on fatigue dimension measured. Among the studies that reported scores for the fatigue subscale of the European Organization for Research and Treatment of Cancer Core Questionnaire for Quality of Life (most studies), mean fatigue levels in cancer survivors ranged from 28.7 to 36.5 out of an overall score of 100, and mean fatigue levels in matched general population controls ranged from 20 to 30 out of 100. No associations between instruments and results were apparent. Although the small numbers of studies prevented comparisons among cancer subtypes, equal positive and negative studies were seen in breast cancer survivors and, notably, no negative studies were seen involving Hodgkin's disease survivors. Most effect sizes calculated were small. Fatigue was a burden to both cancer survivors and members of the general population. While evidence for greater fatigue severity in cancer survivors was mixed, most studies reported greater fatigue in cancer survivors as compared with controls. The magnitude of this effect was generally small. Inferences from the data were limited by variability in both the definition of survivor and the fatigue assessments used, as well as by the cross-sectional design of the studies. Prospective longitudinal studies are needed to determine causal relationships between excessive fatigue and surviving cancer.
Braun
Ilana M
IM
Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, USA. ibraun@partners.org
Greenberg
Donna B
DB
Pirl
William F
WF
D019317:Evidence-Based Medicine; D005221:Fatigue / Q000209:etiology*; D006801:Humans; D009369:Neoplasms / Q000150:complications*; D012720:Severity of Illness Index; D017741:Survivors