title: Pain, depression, and fatigue as a symptom cluster in advanced cancer.
abstract: BACKGROUND
  Pain, depression, and fatigue are common symptoms in cancer populations. They often coexist and have been suggested as a specific symptom cluster. Systemic inflammation (SI) may be a possible common mechanism.
  
  
  OBJECTIVE
  This study examined whether pain, depression, and fatigue exist as a symptom cluster in advanced cancer patients with cachexia and might be related to the presence of SI.
  
  
  METHODS
  Secondary data analysis was undertaken of two clinical trials in patients with cancer cachexia (n = 654). Pain, depression, and fatigue were assessed using the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire-C30. Plasma C-reactive protein (CRP) was measured as a marker of SI in a subgroup (n = 436). Multivariate analysis and a series of regression analyses were undertaken relating pain, depression, fatigue, and CRP.
  
  
  RESULTS
  Pain, depression, and fatigue clustered, with between two and four times as many patients having all three symptoms as would be expected if the symptoms only coexist by chance (P < 0.001). CRP was not related to the symptom cluster. There was a strong relationship between the pattern of symptoms and physical functioning (P < 0.001).
  
  
  CONCLUSIONS
  Pain, depression, and fatigue is an identifiable symptom cluster in a cohort of cachexic cancer patients and is associated with reduced physical functioning.
authors.affiliation: University of Edinburgh, Edinburgh, United Kingdom. barry.laird@ed.ac.uk
authors.forename: Barry J A
authors.initials: BJ
authors.lastname: Laird
authors.forename: Angela C
authors.initials: AC
authors.lastname: Scott
authors.forename: Lesley A
authors.initials: LA
authors.lastname: Colvin
authors.forename: Amy-Louise
authors.initials: AL
authors.lastname: McKeon
authors.forename: Gordon D
authors.initials: GD
authors.lastname: Murray
authors.forename: Kenneth C H
authors.initials: KC
authors.lastname: Fearon
authors.forename: Marie T
authors.initials: MT
authors.lastname: Fallon
mesh_terms: D000368:Aged; D002100:Cachexia / Q000150:complications* / Q000523:psychology; D002986:Clinical Trials as Topic; D016000:Cluster Analysis; D003863:Depression / Q000150:complications* / Q000523:psychology; D005221:Fatigue / Q000150:complications* / Q000523:psychology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000150:complications* / Q000523:psychology; D010146:Pain / Q000150:complications* / Q000523:psychology; D011788:Quality of Life; D011795:Surveys and Questionnaires