THE MULTICENTER ASSESSMENT OF QUALITY-OF-LIFE - THE INTERDISCIPLINARY-GROUP-FOR-CANCER-CARE-EVALUATION (GIVIO) EXPERIENCE IN ITALY

One of the main issues to be considered in conducting clinical trials concerns the presence of missing data. This aspect is particularly rel evant in oncology longitudinal studies, characterized by a long follow -up, and especially in quality of life studies where there is still li ttle knowledge about patients' characteristics that predict loss of da ta. Since the middle of the: 1980s the GIVIO (Interdisciplinary Group for Cancer Care Evaluation) co-operative group has been involved in co nducting quality of life assessment studies, also focusing on the deve lopment of some strategies aimed at the minimization of missing data. In this paper we report on the results of two trials, which are now co mpleted, concerning the quality of life assessment in a sample of brea st and colon cancer patients. In order to cope with the problem of mis sing data, in both the trials the strategy of follow-up mailing was ad opted, which proved to be an effective way to increase the response ra te by nearly 50 per cent at each time point. (C) 1998 John Wiley & Son s, Ltd.