EGFR and non-small cell lung carcinoma: The current prospective, multicenter, observational study showed that a higher mutant-allele frequency of pretreatment T790M in patients with surgically resected EGFR-mutated NSCLC was associated with poorer RFS, independent of male sex, advanced pathological stage, and older age, and was also associated with worse OS, independent of EGFR mutation genotype, advanced pathological stage, older age, and no adjuvant chemotherapy.