QUALITY-ADJUSTED SURVIVAL ANALYSIS OF MALIGNANT GLIOMA PATIENTS

The goal of therapeutic intervention in oncology patients is to prolon g survival without compromising its quality. Definition and measuremen t of quality are quite difficult. This article discusses the statistic al techniques for quantifying quality survival that have been used in brain tumor patients. These techniques assume either that all patients have equivalent baseline quality of life when both disease-related sy mptoms and toxicities are absent, or that the length of time with a pr edetermined level of impairment is equivalent to death. These models d o not fit the heterogeneous symptoms experienced by patients with mali gnant brain tumors. We propose a model that incorporates the baseline states with transitions to different levels of severity that indicate improvement and/or declines in physical and cognitive functioning of b rain tumor patients. The length of time spent in each state is observe d and weighted by using predetermined utilities. The weighted time spe nt in each state is aggregated over all states into a quality-time of survival metric (QTIME). This QTIME model was applied to a previously published, randomized clinical trial of different radiation doses in m alignant brain tumor patients. (C) Elsevier Science Inc. 1997.