Ethnic differential item functioning in the assessment of quality of life in cancer patients

Over the past two decades, quality of life (QoL) research has become an integral endpoint in clinical trials, yet, regarding its implementation in daily clinical work, much hesitation still abounds. This article discusses how complex psychological processes at work within a patient along with environmental factors act upon each other to form what is finally measured in a QoL score. An extended model of QoL is suggested which comprehensively describes the contribution of factors such as common psychological reactions to cancer, coping mechanisms, traits, and socioeconomic conditions to the final outcome in a QoL inventory. In order to avoid disappointment at the utility of results gained in QoL assessment both in clinical trials and daily routine, the choice of appropriate QoL instruments, their goal-directed implementation, and suitable expectations towards the anticipated aims are pivotal aspects to be ensured. Competent utilization of QoL assessment contributes to an enhanced standard of patient-centered care in oncology.