title: The ability of cancer-specific and generic preference-based instruments to discriminate across clinical and self-reported measures of cancer severities.
abstract: OBJECTIVE
  To evaluate the validity of cancer-specific and generic preference-based instruments to discriminate across different measures of cancer severities.
  
  
  METHODS
  Patients with breast (n = 66), colorectal (n = 57), and lung (n = 61) cancer completed the EORTC QLQ-C30 and the FACT-G, as well as three generic instruments: the EQ-5D, the SF-6D, and the HUI2/3. Disease severity was quantified using cancer stage, Eastern Cooperative Oncology Group Performance Status (ECOG-PS) score, and self-reported health status. Comparative analyses confirmed the multi-dimensional conceptualization of the instruments in terms of construct and convergent validity.
  
  
  RESULTS
  In general, the instruments were able to discriminate across severity measures. The instruments demonstrated moderate to strong correlation with each other (r = 0.37-0.73). Not all of the measures could discriminate between different groups of disease severity: the EQ-5D and SF-6D were less discriminative than the HUI2/3 and the cancer-specific instruments.
  
  
  CONCLUSIONS
  The cancer-specific and generic preference-based instruments demonstrated to be valid in discriminating across levels of ECOG-PS scores and self-reported health states. However, the usefulness of the generic instruments may be limited if they are not able to detect small changes in health status within cancer patients. This raises concerns regarding the appropriateness of these instruments when comparing different cancer treatments within an economic evaluation framework.
authors: Canadian Centre for Applied Research in Cancer Control (ARCC), Vancouver, BC, Canada. pteckle@bccrc.ca
authors: Paulos
authors: P
authors: Teckle
authors: Stuart
authors: S
authors: Peacock
authors: Helen
authors: H
authors: McTaggart-Cowan
authors: Kim
authors: K
authors: van der Hoek
authors: Stephen
authors: S
authors: Chia
authors: Barb
authors: B
authors: Melosky
authors: Karen
authors: K
authors: Gelmon
mesh_terms: D000704:Analysis of Variance; D001943:Breast Neoplasms / Q000473:pathology*; D015179:Colorectal Neoplasms / Q000473:pathology*; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D011594:Psychometrics / Q000295:instrumentation*; D011788:Quality of Life; D012650:Self Disclosure; D012720:Severity of Illness Index; D018709:Statistics, Nonparametric; D011795:Surveys and Questionnaires