P1.02-015 A Multicenter Study of EGFR and EML4-ALK Detection in Non-Squamous, Non‒Small-Cell Lung Cancer Patients with Malignant Pleural Effusion

Abstract

Currently, multicenter studies involving a large number of patients have not been not undertaken to detect the frequencies of EGFR mutations and ALK rearrangement in malignant pleural effusion (MPE) samples of patients with non-squamous, non‒small-cell lung cancer (NSCLC), we undertook a multicenter, observational study of Asian patients with untreated stage IV NSCLC. Eligible patients had untreated of EGFR and ALK inhibitor stage IV non-squamous NSCLC patients with MPE. The EGFR and ALK status of MPE and partially paired tumor tissue was determined with reverse transcription polymerase chain reaction (RT-PCR). Among 210 patients with pleural effusion samples confirmed as malignant, 16 had EML4-ALK fusion gene rearrangements and 89 had EGFR mutations. No ALK/EGFR co-altered gene was found. Tumor tissue of 56 patients was collected. EGFR and ALK concordance rates between MPE samples and matched tumor tissue samples from 56 patients were 87.5% (49/56) and 96.1% (49/51), respectively. There was a tendency for a longer progression free survival in patients with EGFR accordance in comparison with those with EGFR discordance between tumor tissue and MPE samples (9.8 vs 6.2 months, respectively; p = 0.078). A same trend was found in patients with ALK accordance and discordance (10.0 vs 3.2 months, respectively; p = 0.004). These results demonstrate that MPE can be substituted for tumor tissues for EGFR and ALK gene detection. Patients with gene mutations or arrangement discordance between tumor tissue and MPE samples showed a inferior efficacy of targeted therapy than those with accordance.