The evolution of quality of life evaluations in cancer therapy.

Patients' feelings, psychological and functional status, and quality of life have often been regarded as unmeasurable subjective entities that cannot be scientifically studied. But now, with better measurement tools, the cancer patient's Quality of Life can be understood in more operational terms than the "soft" subjective statements that have too often characterized the field to date. This paper addresses the issue of Quality of Life from several perspectives: 1. Historical antecedents of the concept; 2. precipitating factors; 3. evolution of the concept; 4. historical development of the measures; and 5. applications of Quality of Life assessments, including implications for research, teaching, and clinical care.