Plasma next generation sequencing and droplet digital PCR‐based detection of epidermal growth factor receptor (EGFR) mutations in patients with advanced lung cancer treated with subsequent‐line osimertinib

Background Gene mutation analysis from plasma circulating tumor DNA (ctDNA) can provide timely information regarding the mechanism of resistance that could translate to personalised treatment. We compared concordance rate of next generation sequencing (NGS) and droplet digital polymerase chain reaction (ddPCR) in the detection of the EGFR activating and T790M mutation from plasma ctDNA with diagnostic tissue biopsy‐based assays. The second objective was to test whether putative osimertinib resistance associated mutations were detectable from plasma using NGS.