A second relevant issue are decisions about patient stratification in clinical trials: for example, when faced with the dilemma of whether to stratify newly diagnosed stage IV EGFR+ NSCLC patients according to the presence or absence of prior early-stage disease, or according to their current brain or ECOG PS status, our results show that stratification according to the baseline characteristics of the current stage IV disease is more important, and actually sufficient (Figures 2 and 3, Table 3). Here, EGFR is linked to non-small cell lung carcinoma.