title: The European Organization for Research and Treatment of Cancer Quality of Life Questionnaire (EORTC QLQ-c30): validation of English version in Singapore.
abstract: OBJECTIVE
  This study aimed to validate the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire (EORTC QLQ-C30, English version 3.0) in Singaporean cancer patients.
  
  
  METHODS
  In a cross-sectional study, a heterogeneous sample of cancer patients (n = 57) self-administered a questionnaire containing the QLQ-C30, the Short Form 36 Health Survey (SF-36) and assessing health and sociodemographic status. Construct validity was assessed by testing a priori hypotheses that QLQ-C30 scales would be moderately or strongly correlated with SF-36 scales measuring similar dimensions of health-related quality of life (HRQoL) and that subjects reporting mild symptoms would have better HRQoL scores than those reporting severe symptoms. Internal consistency reliability was assessed using Cronbach's alpha.
  
  
  RESULTS
  Strength of Spearman's correlations between the QLQ-C30 and SF-36 scales assessing similar dimensions of HRQoL ranged from 0.35 to 0.67. Subjects with mild symptoms had better scores than those with severe symptoms for all six QLQ-C30 HRQoL scales (p < 0.05 for five scales, Mann-Whitney U tests). Cronbach's alpha ranged from 0.19 for the cognitive functioning scale to 0.91 for the global QoL scale.
  
  
  CONCLUSIONS
  This study provides preliminary evidence for the validity and reliability of the EORTC QLQ-C30 in English-speaking Singaporean cancer patients.
authors.affiliation: Department of Pharmacy, National University of Singapore, Singapore.
authors.forename: N
authors.initials: N
authors.lastname: Luo
authors.forename: C S L
authors.initials: CS
authors.lastname: Fones
authors.forename: S E
authors.initials: SE
authors.lastname: Lim
authors.forename: F
authors.initials: F
authors.lastname: Xie
authors.forename: J
authors.initials: J
authors.lastname: Thumboo
authors.forename: S C
authors.initials: SC
authors.lastname: Li
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000503:physiopathology* / Q000523:psychology / Q000628:therapy; D011788:Quality of Life; D018434:Sickness Impact Profile; D012846:Singapore; D011795:Surveys and Questionnaires; D014175:Translating