Clinical, Pathological and Molecular Characterization of Long-Term Survivors with Advanced Non-Small Cell Lung Cancer in a Multicenter Experience in Madrid: Final Results.

e20621 Background: Long survivors (LS) in non-small-cell lung cancer (NSCLC), defined as an overall survival (OS) greater than 2 years, are less than 10% in most series. Classical prognosis factors include stage, weight loss and ECOG, but more information is missing in the literature. Recently, EGFR, ALK and ROS 1 population (less than 20%) reach OS longer than 2 years. Immunotherapy has demonstrated very promising results with more LS compared to chemotherapy in first and second line setting. In this study, we focused in the analysis of LS patients with advanced NSCLC EGFR wt (wild type) and ALK nt (non-translocated), defined as those with OS greater than 36 months, in 7 hospitals in Madrid. Methods: In this serie, first of all, we will try to make a clinical, histopathological characterization collecting data from clinical reports according to a previously defined information. In a second step, we will carry out a genetic analysis of these patient samples comparing to an opposite extreme short survivors (SS) samples (OS less than 9 months). Initially, we used a NGS method of RNA-seq technology to identify differentiating profiles of gene expression between the two opposite populations. And finally, we confirmed this preliminary profile by RT-PCR in the rest of samples. Results: Ninety-six patients were initially included. The majority were men, smokers or former with adenocarcinoma and ECOG 0- 1. We have obtained a differential transcriptome expression between samples from 6 LS and 6 SS, resulting 13 over-expressed and 42 down-expressed genes in LS comparing to SS transcriptome expression. Some of the genes involved in this initial profile belong to different cellular pathways: Secretin Receptor, Surfactant Protein, Trefoil Factor 1, Serpin Family, Ca-bindings Protein channel and Toll like Receptor family. Finally, we carried on by RT-PCR in 40 samples of SS and LS survivors and only four genes were significantly down-regulated in SS compared to LS in the multivariate analysis. These 4 genes were related to Surfactant Proteins: SFTPA1 (p = 0.023), SFTPA2 (p = 0.027), SFTPB (p = 0.02) and SFTPC (p = 0.047). Conclusions: We present a sequential genetic analysis of a LS population with NSCLC EGFR wt (wild type) and ALK nt (non-translocated), obtaining a differential RNA seq- and RT-PCR gene profile based on different surfactant proteins expression. A further confirmation in a larger sample is ongoing.