Reliability and validity of the PORPUS, a combined psychometric and utility-based quality-of-life instrument for prostate cancer.
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.
Ritvo
Paul
P
York University, and Cancer Care Ontario, Division of Preventive Oncology, 620 University Ave., #1236, Toronto, Ontario M5G, Canada. paul.ritvo@cancercare.on.ca
Irvine
Jane
J
Naglie
Gary
G
Tomlinson
George
G
Bezjak
Andrea
A
Matthew
Andrew
A
Trachtenberg
John
J
Krahn
Murray
M
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