Abstract
BACKGROUND: Epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) are currently the primary treatment option for patients with EGFR-mutant non-small cell lung cancer (NSCLC). However, the effect of EGFR-TKIs are eventually weakened due to resistance, and there is also a differential efficacy based on EGFR mutation subtypes. The combination of angiogenesis inhibitor (AI) with EGFR-TKI has shown better efficacy than EGFR-TKI monotherapy, regardless of the mutation subtypes. Nevertheless, the effect of AI eligibility on overall survival (OS) and progression-free survival (PFS) remains to be elucidated. Thus, we assessed this impact on patients with NSCLC harboring EGFR mutation. METHODS: In this study, the data for 450 patients with EGFR-mutant NSCLC, who were treated with EGFR-TKI monotherapy, were retrospectively analyzed for AI eligibility. The patients were categorized into AI-eligible (AI fit) and ineligible groups (AI unfit). RESULTS: The median PFS of the AI fit group was 12.9 months, compared to 9.6 months in the unfit group (p = 0.007), and OS was also significantly longer in the AI fit group (median OS = 33.0 months) compared to that in the unfit group (18.5 months, p < 0.001). Multivariate analysis indicated that AI ineligibility was associated with shorter PFS and poor prognosis. Also, in the AI fit group, there was no significant difference in the PFS between EGFR L858R mutation and EGFR exon 19 deletion (median PFS = 11.5 months vs. 13.8 months; p = 0.17). CONCLUSIONS: From our study, AI eligibility resulted in longer OS and PFS, and also had different effects on patients with EGFR L858R and exon 19 deletion. Since this selection bias may have affected previous clinical trial data on the efficacy of AI combination therapy, their results should be carefully considered henceforth.