Among first-line EGFR-tyrosine kinase inhibitors, afatinib was the most common (44%), followed by gefitinib (28%) and erlotinib (13%). In the second-line treatment, osimertinib was most common (40%).

Discontinuation of first-line treatment was mostly due to disease-progression (81%) and toxicity (7%).

The clinical outcomes of Korean patients with EGFR-mutated metastatic non-small cell lung cancer were comparable with those observed in clinical trials.