MA16.05 For EGFR Mutant Non-Small Cell Lung Cancer, Treatment Sequence Matters?

Abstract

EGFR tyrosine kinase (TKI) showed better progression free survival (PFS) in EGFR-mutant non-small cell lung cancer (NSCLC), but the overall survival (OS) benefit were not clear so far. Treatment sequence may contribute to OS, but there are little data so far. We aimed to analyze the impact of treatment sequence of EGFR TKI and chemotherapy on outcomes in EGFR-mutant NSCLC. Among NSCLC patients who had EGFR exon 18–21 mutation test results between 2009 and 2014 at Seoul St. Mary’s Hospital, 114 patients who had recurrent or metastatic disease, EGFR mutation positive excluding T790M mutation, and received both EGFR tyrosine kinase inhibitor (TKI) and chemotherapy as the 1st or 2nd line of treatment were included. Patients were categorized into two groups according to the treatment sequence: 1st line EGFR TKI followed by chemotherapy (group A), 1st line chemotherapy followed by EGFR TKI (group B). The median follow-up duration was 64.6 (15.8–202.8) months. Among total 114 patients, 69 patients received EGFR TKI first and then chemotherapy (group A), and the remaining 45 patients received vice versa (group B). Group A was younger (P = 0.029) and less frequently received platinum-doublet agents than Group B (P <0.001). Performance status and EGFR mutation status were not different. Overall response or disease control rate were significantly better for EGFR TKI comparing to chemotherapy regardless of treatment sequence. However, PFS on both treatment were longer in group B (P = 0.008), especially for patients with exon 19 deletion (P = 0.002). On multivariate analyses, performance status (P = 0.006 for PFS, P <0.001 for OS) and treatment sequence [hazard ratio (HR) = 0.027, P = 0.027 for PFS; HR = 0.64, P = 0.065 for OS] were related to prognosis. For exon 19 deletion subtype of EGFR-mutant NSCLC patients, the sequence of cytotoxic chemotherapy followed by EGFR TKI showed better PFS comparing with the reverse sequence, EGFR TKI followed by cytotoxic chemotherapy . We will present the data from larger cohorts the WCLC meeting.