Background: T790M mutation is a major mechanism for EGFR-TKI failure. However, few studies explored its correlation with failure patterns and response duration partly due to difficulty in re-biopsy. Droplet digital PCR (ddPCR) is able to detect the frequency and abundance of T790M non-invasively in circulating tumor DNA (ctDNA). Methods: 314 patients with advanced or recurrent NSCLC who had progressed during EGFR-TKIs treatment were enrolled prospectively (NCT02418234).
