Another seven studies (clinical trials or retrospective studies) [8], [11], [13], [26], [27], [28], [29] involving 549 advanced NSCLC patients receiving first-line EGFR-TKIs (gefitinib or erlotinib) presented direct comparison of exon 19 deletion and L858R mutation for PFS. This evidence concerns the gene EGFR and non-small cell lung carcinoma.