Quality-of-life assessment: patient compliance with questionnaire completion.

Previous investigators have found that compliance with quality-of-life data collection on cancer clinical trials is poor. There is general belief that collecting complete quality-of-life data is at present an unachievable goal. We assessed the completeness of quality-of-life data collection on trials instituted by the National Cancer Institute of Canada Clinical Trials Group (NCIC CTG), since incorporation of quality-of-life outcomes into trials became mandatory for the group. Data from three NCIC CTG trials in which quality of life was a study end point were examined to determine the extent to which protocol specifications were met with respect to questionnaire completion. Two of the studies examined adjuvant therapies, and one examined anti-emetics. In two trials, the quality-of-life questionnaire of the European Organization for Research and Treatment of Cancer was used; in the other, the Breast Cancer Chemotherapy Questionnaire. Patient compliance with questionnaire completion was unexpectedly high: More than 95% of the scheduled questionnaires were returned, and more than 99% of the questions were answered. We attribute this success to a comprehensive set of measures taken to enhance compliance on these studies. Which of these measures was most contributory requires further investigation, as does the issue of whether similar results can be obtained in other circumstances. It seems that the commonly held belief that quality-of-life data cannot be successfully collected in multicenter cancer trials is incorrect.