Vergleich zweier unterschiedlicher Erhebungsverfahren zur Bestimmung von Lebensqualität bei Brustkrebspatientinnen. Ist die Einschätzung von Lebensqualität, die im Verlauf einer Brustkrebserkrankung erhoben wird, gleichzusetzen mit derjenigen, die rückblickend erinnert wird?

This study examins, if there is a connection between the quality of life measured prospectively and the quality of life measured retrospectively in breast cancer patients. Is the estimate of quality of life which is raised in the process of a cancer of breast disease to equate with that which is retrospectively reminded? N=389 breast cancer patients were included in the „field study for the regional supply of tumour patients with breast and rectum cancer under special consideration of the quality of life“ within a period of 5 years. From these group a sub-group of 30 breast cancer patients has been interviewed. They were asked to estimate their quality of life with the help of the Cantril-scale „at present“ and by this indication to estimate retrospectively the quality of life at the time „before the diagnosis” , „diagnostic position“, „operation“, „discharge“, „1st follow-up date“, „2nd follow-up date“ and „4th follow-up date“. The EORTC questionnaire was filled in from the patients prospectively on the date of discharge and on each follow-up date. In this questionnaire the question 29 and 30 classify the global quality of life. By linear transformation the prospective EORTC-data are comparable with the retrospective Cantril-data. The formed average values of the EORTC and Cantril questionings show that prospectively (=EORTC) a relatively constant quality of life is measured during the whole period (discharge = 5,9; 1st follow-up = 5,9; 2nd follow-up = 6,4; 4th follow-up = 6,1; date of interview = 6.0). In addition these values are to be found above the average 5 using a scale which rises from 0 to 10. The Cantril average values, which correspond to the reminded quality of life, are always below the EORTC values right up to the time of questioning (discharge = 3,2; 1st follow-up = 4,1; 2nd follow-up = 5,2; 4th follow-up = 5,8; date of interview = 6.1). Based on the assumption that humans want to feel as happy as possible, according to the psychological process of adjustment concerning the level of demand people tend to estimate their global quality of life always somewhat better than the average. This is a known psychological process and it explains the constant values above the scale average „5“ in the prospective measurement (EORTC) as well as in the Cantril measurement at the time of the interview. So called “anchor effects” influence the reminded quality of life: „If I feel good today (6.1), I must have felt worse at the time of discharge (3.2) from today's perspective!“. Addationally, the recollections of series events which are not emotional reminded (= follow-up dates) tend to blur. So their data are more easily subject to influence by for instance the interview situation. For the clinical work it is important to know in which way quality of life is being measured (retrospective or prospektiv).As shown in this study these methodes influence the results of measuring quality of life and their interpretation.