Primary Tumor Resection With EGFR TKI for Stage IV NSCLC

Inclusion Criteria: * Histologically or cytologically confirmed non-small cell lung cancer * Stage IV non-small cell lung cancer which is amenable to thoracic surgery * Patients must have one of the following:NSCLC which harbors EGFR exon 19 deletion or L858R mutation. * Eastern Cooperative Oncology Group (ECOG) performance status =\< 1 * Candidate for therapeutic intent surgery to at least one site of disease * Signed and dated written informed consent prior to admission to the study in accordance with International Council for Harmonization of Technical Requirements for Pharmaceuticals for Human Use (ICH)-Good Clinical Practice (GCP) guidelines and to the local legislation Exclusion Criteria: * Life expectancy \<= 12 weeks * With underlying diseases such as moderate to severe Chronic Obstructive Pulmonary Disease or tuberculosis * With uncontrol diseases including acute infection, unstable angina or angina in recent 3 months, Heart failure(NYHA≥2), myocardial infarction in recent 6 months, severe arrhythmia, moderate to severe cirrhosis, moderate to severe chronic renal insufficiency, immune insufficiency, any systemic disease with poor prognosis after treatment. * With Cerebrovascular Accident complicated dependent activities of daily living. * Any other cancer with active treatment in recent 5 years. * receive thoracic surgery in the ipsilateral site with the lung cancer previously. （the biopsy surgery required for the diagnosis of lung cancer was not excluded) * pregnant or breast-feeding woman * Previous treatment with other EGFR TKI. NOTE: Patients who are receiving initial afatinib (6-12 weeks) outside this study are not excluded * Disagree to receive Next Generation Sequencing for the lesion specimen after surgery.