Research on the Correlation Between Efficacy of Osimertinib and EGFR T790M Status and Ratio Via Digital Droplet PCR (ddPCR) From Peripheral Blood in NSCLC Patients

Liquid biopsy is emerging as an essential tool in tumor monitoring and a potential alternative and supplement to tissue biopsy for tumor genotyping, especially in relapsed or metastatic diseases. Liquid biopsy methods for detecting T790M in ctDNA can be qualitative or quantitative, including amplification refractory mutation system PCR (ARMS-PCR), digital droplet polymerase chain reaction (ddPCR), and next generation sequencing (NGS)-based methods. Comparison of multiple detecting platform for EGFR mutations in plasma samples has been undertaken in studies to determine the most feasible assay in clinical practice. In this study, we will investigate the usefulness of ddPCR for quantitative detection of EGFR T790M mutation in peripheral blood, and compared the utility of ddPCR and NGS for guiding decisions regarding osimertinib therapy in NSCLC patients who had develop resistance to first- or second generation EGFR-TKIs.