EGFR and lung cancer: The various studies tried to identify the impact of double mutations or triple mutations of EGFR in clinicopathology characteristics in lung cancer patients.37,38 All previous studies showed poorer outcomes with multiple mutations compared with single EGFR mutations.37,38 Nevertheless, in this study, double mutations of exon 19 and exon 21 showed a better outcome in both OS and PFS compared with single mutations of exon 19.