Quality of life in cancer: definition, purpose, and method of measurement.

Over the past 20 years, changes within medicine and society have encouraged an expansion in conceptualizing and evaluating the goals and important outcomes of medical treatments. In evaluating the care of people with cancer and other chronic illnesses, a major part of the expansion has been the inclusion of means to assess the quality of life in addition to the quantity of life associated with various treatments. This paper presents a review of the current literature on quality-of-life assessment in oncology research and practice. The review is organized around current thinking about the definition of quality of life, the purpose of quality-of-life measurement, the method of assessment, and the competing advantages and disadvantages of disease-specific versus general health outcome measurement. Recommendations for proceeding with quality-of-life measurement in oncology are provided to encourage increased attention to the need to remain closely tied to a theoretical construct.