Deriving a compound quality of life measure from the EORTC-QLQ-C30/LC13 instrument for use in economic evaluations of lung cancer clinical trials.

Many clinical trials involve parallel collection of quality of life (QoL) and economic data, requiring patients to complete similar questionnaires at regular intervals. This additional burden often leads to disappointing response rates and inconclusive results. Data obtained in the LU-16 trial with the European Organization for Research and Treatment of Cancer Quality of Life (EORTC-QLQ-C30)/LC-13 QoL instrument for lung cancer were re-analysed, using multivariate techniques. The analysis demonstrated the inherent non-linearity of QoL data, with resulting interpretational problems. A new integrated linear QoL measure was developed which maximises the use of the information collected and can serve as a proxy utility measure for economic evaluation. It was successfully validated with data from another lung cancer trial with encouraging results. For individual patients, trends in QoL are revealed more clearly with narrower confidence intervals. This approach yields relative weightings and rankings for the main issues affecting QoL ratings in lung cancer patients, most importantly fatigue, breathlessness, poor concentration and disruption to family and social life.