EGFR and non-small cell lung carcinoma: We found that, in a cohort of 40 EGFR mutation-positive NSCLC patients with acquired EGFR TKI resistance, the cumulative detection rate for the T790M mutation in cfDNA from all five methods was 50% (n = 20): 3 had died before osimertinib therapy, and 13 had stabilized or partially responded after osimertinib therapy.