• Chest. 2014 Mar 1;145(3 Suppl):350A.

Session TitleLung Cancer ISESSION TYPE: Slide PresentationsPRESENTED ON: Saturday, March 22, 2014 at 02:15 PM - 03:45 PMPURPOSE: We perform this analysis to improve the understanding of the clinicopathological characteristics and clinical outcome of non-small cell lung cancer (NSCLC) patients harboring EGFR T790M along with activating EGFR mutation.MethodsIn this series, resected tumors from NSCLC patients at single center were detected for mutation in EGFR, as well as KRAS, BRAF, HER2, EML4-ALK and PIK3CA. Fluorescence in situ hybridization was performed to define EGFR and c-MET gene amplification. Expression of PIK3CA, p-AKT and mTOR were tested using immunohistochemistry. Clinical and pathological data including sex, age at diagnosis, stage, differentiation, smoking status, histological subtype, relapse-free and overall survival were further analyzed.Results16 NSCLC patients were found to harbor primary EGFR T790M mutation, including 14 adenocarcinomas, 2 adenosquamous carcinoma, accounting for 2.04% of all the EGFR mutant cases and 0.84% of total. No c-MET amplification was found to coexist with EGFR T790M. Fewer EGFR FISH-positive cases was found in samples harboring EGFR T790M mutations compared to that in patients with exon 19 deletions and L858R. Overall survival was significantly shorter for patients harboring EGFR T790M mutation than it was for patients with exon 19 deletions (P = 0.008). There was no significant difference in relapse-free survival among 3 subgroups of patients harboring different subtypes of EGFR mutation. (T790M vs. exon 19 deletions, P = 0.387; T790M vs. L858R P = 0.951).ConclusionsOur study described the clinicopathological and molecular characteristics of NSCLC patients harboring primary EGFR T790M mutations. Its value of being a predictor for worse prognosis is established. Primary EGFR T790M mutation is a rare event in NSCLC cases, but the therapy strategies for this subtype of patients should be precisely considered.Clinical ImplicationsOur molecular data in conjunction with the clinicopathological characteristics and clinical outcome can improve the understanding of non-small cell lung cancer (NSCLC) patients harboring EGFR T790M along with activiting EGFR mutation.It may have the potentiality to optimize existing treatment strategies and clinical trial design.DisclosureThe following authors have nothing to disclose: Hang Li, Rui Wang, Haichuan Hu, Yunjian Pan, Lei Wang, Yang Zhang, Yihua Sun, Haiquan ChenNo Product/Research Disclosure Information.

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