EGFR and non-small cell lung carcinoma: According to the guidelines provided by the Japan Lung Cancer Society, European Society of Medical Oncology (ESMO) and National Comprehensive Cancer Network (NCCN), EGFR-tyrosine kinase inhibitors (TKIs) are recommended as the first-line treatment for stage IV NSCLC harbouring EGFR gene mutations, whereas there is a dearth of data on postoperative recurrent stage IV patients in practice-based settings [3–6].