1558PBiomarker status as a mediator of age-related overall survival (OS) in advanced non-small cell lung cancer (aNSCLC)

Abstract Background Risk models for NSCLC have identified age as a prognostic factor, but the relevance of molecular biomarkers to age-related outcomes is undefined. We explored the prevalence of biomarkers by age group and the impact of biomarker status on age-related differences in OS among aNSCLC patients (pts) in a real-world population. Methods Pts with stage IIIB, IV or recurrent metastatic NSCLC (diagnosed 1/1/11 to 11/30/18) were identified in a US-based, EHR-derived, deidentified database (Flatiron Health). Cox proportional hazard regressions evaluated OS by age at aNSCLC diagnosis (dx) (< vs ≥ 50 years), controlling for gender, histology, race, stage, dx year, smoking status, visit site, region and PDL1 status. Sequential and subgroup regressions modeled ALK+, EGFR+ and ROS1+ biomarker status as mediators of the age effect on OS. Results Our sample included 41,024 pts (median age 69 years); median OS was 11 months. Pts