Normative data for functional assessment of cancer therapy: General scale and its use for the interpretation of quality of life scores in cancer survivors

Abstract

The aims of this study were to derive population-based reference values for the Functional Assessment of Cancer Therapy Scale-General (FACT-G) and to investigate the impact of sociodemographic variables (e.g. age, sex, health status) on these quality of life (QOL) scores, and to compare the normative QOL scores with those of various groups of cancer survivors. A random sample of 2 000 members of the Austrian public were sent questionnaires containing the FACT-G and questions relating to demographic data and health status. A total of 968 questionnaires were returned giving an overall response rate of 50.6% (females 48.3%, age 49.3 ± 16.8). Subjects with higher education reported higher QOL values; divorced and widowed persons had significantly lower QOL scores. Higher age was also associated with lower QOL scores. After bone marrow transplantation, patients generally showed lower QOL scores than the age- and sex-matched population-based sample, whilst in breast cancer survivors there was reduced QOL regarding social well-being. Survivors of Hodgkin's disease were found to have higher functional and social well-being scores than those of the general population sample. Sociodemographic variables should always be taken into consideration when interpreting QOL scores. Furthermore, unless patient data are compared with normative values, phenomena such as adaptation and response shift might be missed or misinterpreted.