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. 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.