Validation of a quality of life questionnaire for use in clinical trials for treatment of patients with inoperable lung cancer.

In order to assess the quality of life of patients with inoperable lung cancer, a questionnaire for patient self-administration with 29 variables was designed including the following subjects: psychosocial well-being, medical side-effects, activities of daily living and physical performance. The questionnaire was validated by using a semistructured interview. Thirty-one patients treated for inoperable lung cancer with either radiotherapy (42%), chemotherapy (42%) or a combination of these two treatment modalities (16%) were included in the study. The multitrait-multimethod matrix (MTMM) was used in the analysis of the construct validity. The present validation study showed a high degree of validity for the majority of the items studied. Some of the items showed a low degree of validity, and are subject to future analysis in large scale studies.