The diagnosis and management of cancer can have a major impact on every aspect of a patient's quality of life. Despite its importance, quality of life is rarely a reported outcome in randomized clinical trials in cancer patients. Failure to collect quality-of-life information may reflect a lack of information among researchers and clinicians about the adequacy and relative merits of measures available for assessing quality of life. We reviewed the adequacy of the 17 existing scales for assessing quality of life in cancer patients against characteristics needed for an adequate measure. None of the existing measures met all of the criteria. Recommendations about the relative adequacy of existing scales were made.