title: Cancer-related symptom clusters for symptom management in outpatients after commencing adjuvant chemotherapy, at 6 months, and 12 months.
abstract: OBJECTIVE
  The aim of this secondary data analysis was to investigate symptom clusters over time for symptom management of a patient group after commencing adjuvant chemotherapy.
  
  
  METHODS
  A prospective longitudinal study of 219 cancer outpatients conducted within 1 month of commencing chemotherapy (T1), 6 months (T2), and 12 months (T3) later. Patients' distress levels were assessed for 42 physical symptoms on a clinician-modified Rotterdam Symptom Checklist. Symptom clusters were identified in exploratory factor analyses at each time. Symptom inclusion in clusters was determined from structure coefficients. Symptoms could be associated with multiple clusters. Stability over time was determined from symptom cluster composition and the proportion of symptoms in the initial symptom clusters replicated at later times.
  
  
  RESULTS
  Fatigue and daytime sleepiness were the most prevalent distressing symptoms over time. The median number of concurrent distressing symptoms approximated 7, over time. Five consistent clusters were identified at T1, T2, and T3. An additional two clusters were identified at 12 months, possibly due to less variation in distress levels. Weakness and fatigue were each associated with two, four, and five symptom clusters at T1, T2, and T3, respectively, potentially suggesting different causal mechanisms.
  
  
  CONCLUSIONS
  Stability is a necessary attribute of symptom clusters, but definitional clarification is required. We propose that a core set of concurrent symptoms identifies each symptom cluster, signifying a common cause. Additional related symptoms may be included over time. Further longitudinal investigation is required to identify symptom clusters and the underlying causes.
authors.affiliation: Institute of Health and Biomedical Innovation (IHBI), Queensland University of Technology (QUT), 60 Musk Avenue, Kelvin Grove, QLD, 4059, Australia. h.skerman@qut.edu.au
authors.forename: Helen M
authors.initials: HM
authors.lastname: Skerman
authors.forename: Patsy M
authors.initials: PM
authors.lastname: Yates
authors.forename: Diana
authors.initials: D
authors.lastname: Battistutta
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000970:Antineoplastic Agents / Q000627:therapeutic use*; D017024:Chemotherapy, Adjuvant / Q000379:methods; D016000:Cluster Analysis; D006970:Disorders of Excessive Somnolence / Q000453:epidemiology / Q000209:etiology; D005163:Factor Analysis, Statistical; D005221:Fatigue / Q000209:etiology; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000188:drug therapy / Q000503:physiopathology*; D010045:Outpatients; D011446:Prospective Studies; D013997:Time Factors; D055815:Young Adult
chemical_list: D000970:Antineoplastic Agents