P3.02b-089 Treatment of NSCLC Patients with Malignant Pleural Effusion Harboring Exon 19 and 21 EGFR Mutations after First-Line and Second-Line TKIs: Topic: EGFR Clinical

Abstract

Recent studies demonstrated a significantly increased frequency of epidermal growth factor receptor (EGFR) gene mutations in non-small cell lung cancer (NSCLC) patients with malignant pleural effusions (MPEs). However, the sensitivity of tyrosine kinase inhibitors (TKIs) in NSCLC patients with MPE for different EFGR mutations was less reported. The purpose of this study is to investigate the effect of first-line and second-line EGFR-TKIs in the treatment of NSCLC with MPEs harboring exon 19 deletion and L858R mutation. From 2010 to 2015, 203 NSCLC patients with MPEs harboring EGFR mutation treated with EGFR-TKIs were reviewed. The efficacy were evaluated with Pearson chi-square or Fisher's exact tests, Log-rank test and Cox proportional hazards model. The objective response rate (ORR) and disease control rate (DCR) for patients treated with first-line and second-line EGFR-TKIs were 21.9%, 91.4% and 14.7%, 85.3%, respectively. The overall median PFS and OS of enrolled NSCLC patients with MPE were 9.3 months (95% Cl, 8.4-10.2 months), 20.9 months (95% Cl, 18.9-22.9 months) after first-line TKIs, and 7.6 months (95% Cl, 6.6-8.6 months), 15.3 months (95% Cl, 13.6-15.9 months) after second-line TKIs, respectively. The exon 19 deletion arm had a longer median PFS (9.4 vs. 7.1 months, p=0.003) and OS (16.8 vs. 13.8 months, p=0.003) compared with the L858R mutation arm after second-line TKIs. ECOG PS (PFS: P=0.004; OS: P=0.01) and TNM stage (PFS: P<0.001; OS: P=0.002) were independent predictors of PFS and OS for NSCLC patients with MPE treated by first-line TKIs. ECOG PS (0-1) (PFS: p=0.004; OS: p<0.001), TNM stage (IVa) (PFS: p=0.04; OS: p=0.007) and exon 19 deletions (PFS: p=0.02; OS: p=0.02) were related to a longer PFS and OS for patients treated with second-line TKIs. Gender was also an independent predictor of OS (p=0.04) for patients treated with second-line TKIs. There was no significant difference on side effects between NSCLC patients with exon 19 and 21 mutations in the first or second-line EGFR-TKIs. EGFR genotype was an independent predictor of PFS and OS. No significant side effects differences between the two mutation groups was observed for first or second-line EGFR-TKIs. This study demonstrated that EGFR mutations are significant predictors for advanced NSCLC patients with MPE receiving second-line EGFR-TKIs treatment.