title: The concept of symptom cluster.
abstract: OBJECTIVE
  To define the concept of a symptom cluster, evaluate the evidence base in support of it, and address research and clinical implications.
  
  
  METHODS
  Review of descriptive research that examined fatigue, insomnia, pain, or depression in relation to other symptoms.
  
  
  CONCLUSIONS
  More investigation is needed. There is evidence of overlapping variance indicative of a relationship between or among symptoms. Few studies have addressed the outcomes of symptom clusters. There is limited evidence of symptom concurrence or a common biological pathway for clustered symptoms.
  
  
  CONCLUSIONS
  Consideration should be given to assessment and management of fatigue, insomnia, pain, and depression as potential "sentinel symptoms" that could affect patient outcomes.
authors.affiliation: Nursing Research, Fax Chase Cancer Center, Philadelphia, PA, USA. Andrea.Barsevick@fccc.edu
authors.forename: Andrea M
authors.initials: AM
authors.lastname: Barsevick
mesh_terms: D000701:Analgesics, Opioid / Q000009:adverse effects; D016000:Cluster Analysis; D019317:Evidence-Based Medicine; D006801:Humans; D009369:Neoplasms / Q000503:physiopathology*
chemical_list: D000701:Analgesics, Opioid