Measuring quality of life: an emerging science

Quality of life (QOL) variables are increasingly included as end points in cancer therapy trials, supplementing such traditional end points as survival time in evaluating the effects of cancer treatments. Consensus has been reached that a number of QOL components (symptom status and physical, emotional, role, and social functioning) should be measured. Assessing multiple health-related QOL dimensions, as compared with a global score, provides a more detailed accounting of specific effects of cancer treatment on patient functioning. Southwest Oncology Group QOL assessment policies emphasize patient reports and the need for systematic quality control procedures. The Southwest Oncology Group QOL questionnaire comprises a battery of categorical scales with established psychometric properties. A set of generic core scales is always included in the battery, and treatment- and disease-specific scales are developed for each trial. Other frequently used QOL questionnaires, such as the European Organization for Research and Treatment of Cancer QLQ-C30, the Cancer Rehabilitation Evaluation System questionnaire, and the Functional Assessment of Cancer Therapy are alternative instruments in current use. Quality of life findings from lung cancer clinical trials indicate a prevalence of symptom distress, fatigue, and decline in functional status, although patients also experience symptom management problems without treatment. A summary of preliminary QOL findings for two vinorelbine (Navelbine; Burroughs Wellcome Co, Research Triangle Park, NC; Pierre Fabre Médicament, Paris, France) trials (randomized and single-arm) in patients with non-small cell lung cancer show that symptom status was as good or better for patients receiving vinorelbine compared with those receiving 5-fluorouracil/leucovorin in the randomized study. Differences in other QOL dimensions were not detected. Findings for the single-arm trial of oral vinorelbine were generally consistent with those of the randomized trial.