What has been learned from measuring health-related quality of life in clinical oncology.

The measurement of health-related quality of life (HRQL) in oncology clinical trials has come of age. Most cooperative clinical trials groups as well as individual institutions have either been measuring, or are starting to measure, HRQL. Over the past decade, much has been learned about how to incorporate HRQL components into multicentre, randomised controlled (phase III) trials and how to collect the data with reasonably low levels of missing information. A selective review, focused primarily on phase III studies, shows that HRQL data are useful for deciding which treatment is preferable when survival rates are similar and for determining whether changes in HRQL, as compared with baseline levels, are related to a treatment or intervention. HRQL information is improving our knowledge of the effects of diseases and their treatments on the patient's ability to function and sense of well-being, and HRQL status is proving to be a more accurate predictor of survival than is performance status. Much more remains to be done, but it is apparent that the inclusion of HRQL in clinical trials has been informative and useful. The increasing frequency of HRQL assessment in clinical trials is evidence of the emergence of a patient-centred philosophy in clinical medicine which, in time, will modify the disease-oriented paradigm under which medical professionals have functioned for the past century.