EGFR and non-small cell lung carcinoma: The proportion of patients with detectable ctDNA varies by indication,14 stage of disease,15 tumor burden, tumor location and other biological characteristics that may be unrelated to the tumor.16, 17 In EGFR‐mutated NSCLC patients who progress during first‐line TKI treatment, the frequency of false‐negative results for p.T790M detection in ctDNA remains high (approximately 20%‐30%).