Survival Analysis of 159 Patients With Advanced Non-Small-Cell Lung Cancer Resistant to First-Generation Epidermal Growth Factor Receptor-Tyrosine Kinase Inhibitor

BACKGROUND: Epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) have limited or no response in some certain patients of non-small-cell lung cancer (NSCLC). However, real-world survival analyses comparing clinical data and EGFR-plasma mutation are still lacking. METHODS: In total, 159 patients with advanced NSCLC resistant to first-generation EGFR-TKIs were included for consecutive blood sampling in this study. Super-amplification refractory mutation system (Super-ARMS) was used to detect EGFR-plasma mutations and correlations between survival and circulating tumor DNA (ctDNA) were analyzed. RESULTS: Among 159 eligible patients, the T790M mutation was detected in 27.0% (43/159) of patients. The median progression-free survival (mPFS) was 10.7 months in all patients. Survival analysis revealed that patients with the T790M mutation had shorter progression-free survival (PFS) than those with the T790M wild-type (10.6 months vs 10.8 months, P = .038). Patients who cleared EGFR-plasma mutation had prolonged PFS compared with those with nonclearing EGFR-plasma mutation (11.6 months vs 9.0 months, P = .001). Cox multivariate analysis showed that the nonclearance of EGFR-plasma mutations was an independent risk factor for PFS (RR = 1.745, 95% CI: [1.184, 2.571], P = .005). The T790M mutation was associated with nonclearance of the EGFR-plasma mutation (χ(2) = 10.407, P = .001). CONCLUSION: Patients with advanced NSCLC who were resistant to the first-generation EGFR-TKI had a prolonged PFS with clearance of EGFR-plasma mutation. Those nonclearers were more likely to harbor T790M mutations in plasma.