Comparison of the efficacies of first-generation epidermal growth factor receptor tyrosine kinase inhibitors for brain metastasis in patients with advanced non-small-cell lung cancer harboring EGFR mutations

Abstract

Background: Compared with standard chemotherapy, epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) are more effective in patients with advanced non-small-cell lung cancer (NSCLC) harboring EGFR mutations. However, data comparing the efficacies of different EGFR-TKIs, especially regarding the presence of brain metastasis, are lacking. Methods: EGFR-TKI naive patients with recurrent or stage IIIB/IV NSCLC harboring EGFR mutations, excluding resistance mutations, were enrolled in this study. We retrospectively determined progression-free survival (PFS) using the Kaplan-Meier method with log-rank test in patients treated with either gefitinib or erlotinib, cumulative incidence of central nervous system (CNS) progression using the Fine and Gray competing risk regression model, and favorable prognostic factors for CNS progression by multivariate analysis. Results: Seventy-seven EGFR-TKI-naive patients were started on either gefitinib (n = 55) or erlotinib (n = 22) in our hospital from April 2010 to April 2016. Among the patients with brain metastasis, PFS tended to be longer in the erlotinib than in the gefitinib group. In the analysis of cumulative incidence, the probability of CNS progression was lower in the erlotinib group than in the gefitinib group. Particularly, in a subgroup analysis of the patients with brain metastasis, there was a significant difference between the erlotinib and gefitinib groups (hazard ratio 0.25; 95% confidence interval, 0.08-0.81; p = 0.021). Of the prognostic factors for CNS progression evaluated, the absence of brain metastasis before EGFR-TKI therapy and receiving erlotinib (vs gefitinib) had a significantly favorable effect on patient prognosis. Conclusion: Although this was a retrospective analysis involving a small sample size, erlotinib is potentially more promising than gefitinib for treatment of brain metastasis in patients with EGFR-mutant NSCLC.