Quality of life as a prognostic indicator of survival: A pooled analysis of individual patient data from canadian cancer trials group clinical trials

Abstract

BACKGROUND: The aims of this study were to externally validate an established association between baseline health-related quality of life (HRQOL) scores and survival and to assess the added prognostic value of HRQOL with respect to demographic and clinical indicators. METHODS: Pooled data were analyzed from 17 randomized controlled trials opened by the Canadian Cancer Trials Group between 1991 and 2004; they included survival and baseline HRQOL data from 3606 patients with 8 different cancer sites. The models included sex, age (≤60 vs >60 years), World Health Organization performance status (0 or 1 vs 2-4), distant metastases (no vs yes), and 15 European Organization for Research and Treatment of Cancer (EORTC) Core Quality-of-Life Questionnaire (QLQ-C30) scales. Analyses were conducted with multivariate Cox proportional hazards models and were stratified by cancer site. Harrell's discrimination C-index was used to calculate the predictive accuracy of the model when HRQOL parameters were added to clinical and demographic variables. The added value of adding HRQOL scales to clinical and demographic variables was illustrated with Kaplan-Meier curves. RESULTS: In the stratified, multivariate model, HRQOL parameters—global health status (hazard ratio [HR], 0.97; 95% confidence interval [CI], 0.95-1.00; P