The main purpose of this study is the identification, description, and segmentation of non-small cell lung cancer (NSCLC) patients based on their value appraisal of treatment outcomes and all intermediate states of health, to obtain patient preferences in direct correlation with clinical data from patients suffering from NSCLC (stage IIIB / IV) who are in transition from 1st to 2nd line treatment, and to gain utility scores by health state derived from patients' perceived value and taken from their perspective.