Previous clinical trials recommended that 40 mg afatinib daily should be the starting dose in patients whose lung cancer harbors EGFR mutations, however, this dosage was often accompanied by serious ADRs and up to 28 to 53.3% of patients required dose reduction in the LUX-Lung 3 and LUX-Lung 6 studies [14, 18]. This evidence concerns the gene EGFR and lung cancer.