Analysis of Re-biopsy Specimens in Advanced NSCLC With Acquired Resistance of EGFR-TKI Targeted Therapy

With the deepening of the concept of tumor management, it is necessary to monitor the patient's gene during the course of treatment, especially in patients with acquired resistance of the first generation EGFR-TKI. Re-biopsy can effectively provide tissue samples as a "gold standard" for gene detection samples. While, the plasma circulating tumor DNA (ctDNA) detection is an important sample of gene detection and the treatment when tissue samples cannot be assessed. However, due to tumor heterogeneity and ctDNA detection technique sensitivity, plasma ctDNA and tissue samples of the test results are inconsistent. Therefore, the difference between re-biopsy tissue samples and plasma ctDNA samples will provide strong evidence for the application of plasma ctDNA in TKI-resistant patients. The study was designed as a prospective and single center study. Fifty patients will be enrolled into the study and the clinical data of patients, including smoke history, cancer history, location, pathology, gene mutation status and so on of the first biopsy samples will be collected and recorded in a case report form. For patients recruited in the study, lesions which were assessed as progressive disease(PD) will be obtained by interventional pulmonology technology. And about 20ml peripheral blood will be collected at the same time. The tissue will be divided into two parts, one part was sent to Pathology Department of Shanghai Chest Hospital and will be processed with paraffin-embedded, and for those diagnosed NSCLC, the other part will be extracted with DNA and performed NGS for the qualified DNA sample and using Cobas to detect the T790M mutation. The matched peripheral blood will also be extracted with DNA and performed NGS and ddPCR.