Prognostic factor analysis of health-related quality of life data in cancer: a statistical methodological evaluation

A significant body of research exists in oncology to identify and evaluate prognostic factors, historically focused on histology, clinical stage and laboratory parameters. Recent evidence suggests that patient self-reported health-related quality-of-life (HRQOL) data provide additional prognostic information. A review by Gotay et al. of published prognostic analyses reports on the usefulness of patient-reported outcomes (PROs), including HRQOL, in predicting survival in cancer patients in clinical trials. An impressive number of studies have found a positive relationship that supports an independent association between HRQOL and survival. However, due to the considerable diversity in, for example, patient groups, types of HRQOL measures used and analytical strategies, current evidence is far from conclusive. This paper examines the statistical research methods employed, discusses key issues for HRQOL prognostic factor-analysis parameters and proposes recommendations for future outcome research.