title: Reliability and validity of the PORPUS, a combined psychometric and utility-based quality-of-life instrument for prostate cancer.
abstract: BACKGROUND
  Although utility-based quality-of-life instruments are often used in economic evaluations and psychometric instruments in treatment evaluations, these are complementary approaches to assessing outcomes. In this study we developed and tested these two forms of quality-of-life instruments, both based on a single, validated, health classification system.
  
  
  OBJECTIVE
  To assess the measurement properties (reliability and validity) of two newly developed psychometric and utility-based instruments for assessing outcomes associated with prostate cancer.
  
  
  METHODS
  141 men with cancer of the prostate (CaP), treated with radical prostatectomy, radiation therapy, hormonal therapy, and/or chemotherapy were assessed with both instruments and other standard psychometric and utility-based instruments.
  
  
  RESULTS
  Analyses indicate the test instruments are reliable and valid. Full-scale correlations between the instruments and standard instruments indicate validity, as do correlations of key subscales, and an evaluation of linear associations with the UCLA-Prostate Cancer Symptom Scales.
  
  
  CONCLUSIONS
  Evidence from this study supports the reliability and construct validity of the tested instruments. Prostate cancer outcomes can now be assessed by a combination of psychometric and utility-based methods, allowing a ready comparison of derived outcomes.
authors.affiliation: York University, and Cancer Care Ontario, Division of Preventive Oncology, 620 University Ave., #1236, Toronto, Ontario M5G, Canada. paul.ritvo@cancercare.on.ca
authors.forename: Paul
authors.initials: P
authors.lastname: Ritvo
authors.forename: Jane
authors.initials: J
authors.lastname: Irvine
authors.forename: Gary
authors.initials: G
authors.lastname: Naglie
authors.forename: George
authors.initials: G
authors.lastname: Tomlinson
authors.forename: Andrea
authors.initials: A
authors.lastname: Bezjak
authors.forename: Andrew
authors.initials: A
authors.lastname: Matthew
authors.forename: John
authors.initials: J
authors.lastname: Trachtenberg
authors.forename: Murray
authors.initials: M
authors.lastname: Krahn
mesh_terms: D000368:Aged; D006801:Humans; D008297:Male; D017060:Patient Satisfaction; D011379:Prognosis; D011471:Prostatic Neoplasms / Q000523:psychology*; D011594:Psychometrics / Q000295:instrumentation / Q000379:methods; D011788:Quality of Life / Q000523:psychology*; D015203:Reproducibility of Results