EGFR and non-small cell lung carcinoma: The third-generation epidermal growth factor (EGFR) tyrosine kinase inhibitor (TKI) osimertinib is approved for front-line use as well as for use as a second-line treatment when EGFR-mutant, non-small cell lung cancer (NSCLC) becomes resistant to erlotinib, afatinib or gefitinib.