The frequency of EGFR mutations in patients with stage III inoperable adenocarcinoma or non-squamous cell carcinoma is 17-31%, which is relatively low. Compared to patients with EGFR wild type, the efficacy of radiotherapy or chemo-radiotherapy may be different in EGFR mutant patients. Some small sample studies showed, compared with patients with EGFR wild type, patients with EGFR mutations have a lower risk of local recurrence and a higher risk of distant metastasis under the standard treatment for stage III lung cancer, which demonstrate the strength of systemic therapy may help. Radiotherapy combined with EGFR-Tyrosine kinase inhibitors(TKI) is a feasible treatment strategy. In view of the low mutation frequency and few prospective research results, the investigators try to explore the survival differences of three treatment strategies used in clinical practice based on the real world data. The investigators will obtain a cohort of patients from multiple large cancer centers in China and try to unravel the efficacy of "radiotherapy combined with EGFR-TKI", which may provide some evidences for the further study.
