P2-17-4 - The Relationships of pfs, pps and Tumor Response with Os in Patients with Nsclc Treated with Gefitinib as First-Line

Abstract

Background: The effects of first-line chemotherapy on overall survival(OS) might be confounded by subsequent therapies in patients with non-small cell lung cancer(NSCLC) harboring EGFR mutation. We retrospectively examined whether progression-free survival(PFS), post-progression survival(PPS), or tumor response could be valid surrogate endpoints for OS after first-line chemotherapy with gefitinib in advanced NSCLC harboring EGFR mutation in our institute.Patients and methods: Between January 2006 and June 2012, 35 patients with advanced NSCLC treated with gefitinib as first-line chemotherapy were analyzed. The relationships of PFS, PPS, and tumor response with OS were analyzed at the individual level. Male/female = 11/24; Median age was 67 years(range: 45 to 88); adenocarcinoma/others = 35/0; stageIIIB/IV = 3/32; ECOG PS0/1/ ≥ 2 = 15/17/3; EGFR mutation ex19del/ex21L858R/others = 20/15/0; Number of regimens after progression 0/1/2/3/4/5/ ≥ 6 = 11/6/6/3/5/1/3.Results: Spearman rank correlation analysis and linear regression analysis showed that PPS was strongly correlated with OS(r = 0.85, P < 0.05, (R2 = 0.86), PFS was not correlated with OS(r = 0.13, P < 0.05, (R2 = 0.001). tumor shrinkage was not also correlated with OS(r = 0.08, P < 0.05, (R2 = 0.01). Performance status at the end of first-line treatment, the best response to second-line treatment, and number of regimens used after progression following first-line chemotherapy were significantly associated with PPS(P < 0.05).Conclusions: Analysis of individual-level date suggested that PPS could be used as a surrogate for OS in patients with advanced NSCLC with EGFR mutation.Our findings suggest that subsequent treatment after disease progression following first-line chemotherapy with gefitinib for the patients with advanced NSCLC harboring EGFR mutation may greatly influence OS.