EGFR and non-small cell lung carcinoma: Multivariate analysis confirmed that both EGFR‐TKI treatment (osimertinib hazard ratio [HR] 0.06, 95% confidence interval [CI] 0.01–0.30; afatinib HR 0.09, 95% CI 0.02–0.39) and a low T790M ratio (HR 0.29, 95% CI 0.12–0.69) were independently favorable prognostic factors for patients with de novo T790M+ NSCLC.