Measuring the effect of cancer on health-related quality of life.

Measuring health-related quality of life in patients with cancer has focused primarily on the development of reliable and valid instruments (questionnaires), and on the effect of chemotherapy in phase III clinical trials. From this research several important lessons have emerged, such as: (i) the need to measure multiple domains; (ii) the importance of self-rating; (iii) the reports of counter-intuitive results; (iv) the ability to quantify the effects of symptoms on health-related quality of life; and (v) the prognostic value of health-related quality of life measurement for survival. Many challenges lie ahead. Among these are the difficulties encountered by medical clinicians in choosing appropriate instruments to measure health-related quality of life, the dilemma of choosing between aggregate scores and domain scores, questions surrounding the significance of results, and whether measurement of health-related quality of life is now at a point where it can be used in routine practice outside of the clinical trials setting. Although further research is required in all of these and other areas, the future for health-related quality-of-life measurement in oncology is promising.