Gefitinib Combine Radiotherapy as Therapy for Patients With NSCLC Harbouring Sensitive Mutations of EGFR

Inclusion Criteria: * Written informed consent provided. * Males or females aged ≥18 years, \< 75 years. * Target population is completely resected pathological stage IIIA-N2 NSCLC with EGFR exon 19 deletions and exon 21 L858R activating mutation. * Underwent radical resection * The patient did not receive any neoadjuvant chemotherapy or EGFR-TKI targeted therapy before surgery * Patient who can start the investigational therapy within 3-6 weeks after the complete resection * ECOG performance status 0-1. * Life expectancy ≥12 weeks. * Adequate hematological function: Absolute neutrophil count (ANC) ≥2.0 x 109/L, and Platelet count ≥100 x 109/L, and Hemoglobin ≥9 g/dL (may be transfused to maintain or exceed this level). * Adequate liver function: Total bilirubin ≤ 1.5 x upper limit of normal (ULN), Aspartate aminotransferase (AST), alanine aminotransferase (ALT) ≤ 2.5 x ULN in subjects without liver metastases; ≤ 5 x ULN in subjects with liver metastases. * Adequate renal function: Serum creatinine ≤ 1.25 x ULN, or ≥ 60 ml/min. * Female subjects should not be pregnant or breast-feeding. Exclusion Criteria: * Patients with prior exposure to agents directed at the HER axis (e.g. erlotinib, gefitinib, cetuximab, trastuzumab). * Patients with prior any systemic chemotherapy, immunotherapy or biotherapy * Known severe hypersensitivity to gefitinib or any of the excipients of this product. * Patients with prior radiotherapy. * Not fully recovered from the previous surgery. * History of another malignancy in the last 5 years with the exception of the following: basal cell carcinoma of the skin and in situ carcinoma of the uterine cervix. * Patients who harbouring exon 20 T790M mutation. * Patient who has any active infection (e.g. acute pneumonia, hepatitis B or hepatitis C). * Dysphagia or known malabsorption of drugs. * Patient with serious heart, liver, kidney or other important organ dysfunction. * Pregnancy or lactation women or women may be positive for pregnancy before the first medication. * Patient has fertility but not willing to take contraceptive measures or whose sexual partners are unwilling to take contraceptive measures. * Researcher believes the patient's condition is not suitable for the clinical study. * Researcher judged the patient's lack of compliance with the study. * Known severe hypersensitivity to gefitinib or any of the excipients of this product.