third generation of EGFR-TKIs is the newest target therapy for NSCLC. However, we did not known the specific mechanisms for those non-responders and patients grow resistance.Next generation sequencing is current the most sensitive and specific method to exam gene mutation, diversion etc.

By consistently detect the cf-DNA, we could possibly find out the mechanisms of response and resistance.

Study backgroud: third generation of epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) is the newest target therapy for non small cell lung cancer (NSCLC). Two major study published in NEJM show that the overall response rate is about 60%-70%, with a progression free survival about 10 months. However, we did not known the specific mechanisms for those non-responders and patients grow resistance.

Next generation sequencing is current the most sensitive and specific method to exam gene mutation, diversion etc. By consistently detect the cf-DNA, we could possibly find out the mechanisms of response and resistance.

Eligible patients received 3rd generation EGFR-TKIs (AZD9291 and AVITINIB) were enrolled into this study. Tumor tissue sample within 6 months, and 10ml periphereal blood samples were collected at baseline. After treatment initiation, 10ml periphereal blood would be collected at every image testing time point until disease progression. Blood samples will be draw using EDTA tube and centerfuged within 2 hours and store in -80 refrigerator.

NGS testing will cover target genes of NSCLC.

Inclusion Criteria:

• pathologically confirmed non small cell lung cancer.
• harboured with positive EGFR mutation (19 exon deletion, L858R、G719X、L861Q mutation)
• reliable patients history data.

Exclusion Criteria:

• pathologically not confirmed non small cell lung cancer.
• multiple primary cancer.

Patients with advanced non-small cell lung cancer (NSCLC),prepare to receive third generation of epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) treatment. Patients must harboured with positive EGFR mutation (19 exon deletion, L858R、G719X、L861Q mutation), able to provide periphereal blood and tumor tissue.