EGFR T790M detection and osimertinib treatment response evaluation by liquid biopsy in lung adenocarcinoma patients with acquired resistance to first generation EGFR tyrosine kinase inhibitors

Background Lung adenocarcinoma with EGFR activating mutations will inevitably acquire resistance to first generation TKIs. Acquired EGFR T790M mutation causes about 50% of these resistance cases. Droplet digital PCR (ddPCR) and cobas enables quantification of T790M mutation. Whether these methods can predict clinical response of osimertinib treatment is unknown.