Clinical features of squamous cell lung cancer with targetable gene alterations in a nationwide genomic screening network in Japan (LC-SCRUM-Japan).

Abstract

9057 Background: Molecular-targeted therapies for precision medicine in squamous cell lung cancer (SqLC) have not yet been established. To identify precise patients for targeted therapies and to reveal their clinical characteristics, we have operated clinical sequencing of advanced SqLCs in our nationwide genomic screening project in Japan (LC-SCRUM-Japan) since March 2015. Methods: As of December 2016, 190 institutions across Japan were participating and 263 advanced SqLC patients had been enrolled in this project. Submitted tumor samples were subjected to a next-generation sequencing system, Oncomine™ Comprehensive Assay, enabling the simultaneous analysis of 143 cancer-related genes. Results: The median age of the 263 patients was 74 years (range, 27-87 years). Two hundred thirty (87%) were male and most patients (97%) were smokers. Among 211 available samples, potentially targetable gene alterations were detected in 58 (27%). Based on these gene alterations, the patients were subdivided into 4 groups, consisting of 25 (12%) with genetic alterations of FGFR family (FGFR type; 23 FGFR1 amplifications, 1 FGFR2 amplification and 1 FGFR3 fusion), 20 (9%) with genetic alterations of the PI3K pathway (PI3K type; 10 PIK3CA mutations, 8 PTEN mutations and 2 AKT mutations), 15 (7%) with other oncogene alterations (KRAS/EGFR/ALK type; 10 KRAS mutations, 3 EGFR mutations and 2 ALK fusions) and others. Comparative analyses of clinical characteristics between the 4 types showed that brain metastases were significantly more frequent in the FGFR type than the others (24% vs. 5%, p = 0.0007), and females (40% vs. 11%, p = 0.0009) and never-smokers (21% vs. 3%, p = 0.0004) were significantly frequent in the KRAS/EGFR/ALK type compared to the others. The prognostic significance of these genetic alterations has not yet been evaluated because of short follow-up time (median, 8.5 months). Conclusions: A series of potentially targetable gene alterations have been identified in SqLC patients. The SqLC patients had distinct clinical features according to the molecular subtypes, and genotype-directed therapeutic strategy should be developed for the individual subtypes.