To evaluate the characteristics of genetic variationmutations at baseline and 3 weeks after oxitinib treatment in EGFRm NSCLC

Characteristics of EGFR gene mutation and efficacy of oxitinib treatment at baseline and after 3 weeks of treatment.To evaluate the mechanism of oxitinib treatment resistance and describe the characteristics of genetic variation associated with oxitinib treatment at baseline and 3 weeks after treatment.

Inclusion Criteria:

1. ≥18 years old male or female
2. Stage IV metastatic or recurrent non-squamous NSCLC that is newly diagnosed, histologically proven and not suitable for radical surgery or radiotherapy (AJCC V8);
3. Without prior systemic antitumor therapy including EGFR-TKI or immunotherapy;
4. EGFR positive in blood or tissue tested in local laboratory;
5. Sufficient blood samples can be provided for molecular detection;
6. Signed informed consent forms are available.

Exclusion Criteria:

1. Patients were unable to collect plasma samples at baseline;
2. The EGFR mutant status of the patient's blood specimen at baseline has not been verified by the central laboratory;
3. The patient refused subsequent treatment with oxitinib; 4）The investigator determines that may affect the conduct of the clinical study and the judgement of the study results.

stage IV metastatic or recurrent non-squamous EGFR-positive NSCLC