EP1.01-41 Feasibility of EBUS-TBNA Cytologies for an Extensive Assessment of Predictive Biomarkers in Lung Cancer

Clinical guidelines support the determination of several driver genes as well as PD-L1 to drive treatment decisions in non-small cell lung cancer (NSCLC). Endobronchial-ultrasound transbronchial needle aspiration (EBUS-TBNA) cytology specimens are useful for the initial diagnosis of NSCLC, although its capacity to provide enough material for a complete genotyping remains controversial. The aim of this study is to determine the yield of EBUS for a comprehensive multiplex genotyping in patients (pts) with suspected NSCLC. In this single-center, ongoing, prospective study, samples from mediastinal lymph nodes were obtained from pts undergoing EBUS-TBNA for lung cancer diagnosis/staging. Following malignant confirmation and appropriate cell content by rapid on-site evaluation, the study sample was obtained and formalin-fixed paraffin-embedded (FFPE). Three analytes were evaluated (DNA/RNA/protein). DNA and RNA were extracted and analyzed by Oncomine Solid Tumour panel (22 genes) and a customized nCounter panel (ALK, ROS; RET, NTRK, METDe14). Tumor Proportion Score (TPS) for PD-L1 protein expression was evaluated by an expert pathologist and scored into <1% (negative), 1-49% (weakly positive) and 50% (high). Twenty-five pts with NSCLC have been included and cytology samples of 20 of them molecularly characterized (5 still in progress). Overall, cytological analysis of EBUS-TBNA yield a complete characterization for the three analytes (DNA/RNA/protein) in 15 pts (75%). EBUS-TBNA sampling was sufficient for both, Nanostring and Oncomine evaluation, in a total of 18 pts (90%): 15 patients (83%) had any alteration detected by oncomine (TP53 61% [11/18],KRAS 44% [8/18], EGFRe 195.5% [1/18], BRAF V600E 5,5% [1/18], DDR2 5.5% [1/18], STK11 11% [2/18]) and 1 pt (5.5 %) by nanostring (METDex14). A total of 19 samples were sufficient for PD-L1 expression scoring (95%). TPS for PD-L1 expression was negative in 8 pts (42%), week in 4 (21%) and high in 7 pts (37%). Overall, half of the pts evaluated (10/20) would be potential candidates for an upfront personalized treatment strategy using targeted agents or immunotherapy. EBUS-TBNA is a promising alternative source of material for NSCLC genotyping and allows the identification of pts candidates for personalized therapies.