Molecular profile of malignant pleural effusion (MPE) in non-small cell lung cancer (NSCLC)

<bold>Introduction:</bold> MPE is known to be related with EGFR, but most studies are small and made in Asian populations. Being able to determine biomarkers can make a difference in survival through individualized treatment. <bold>Objective:</bold> analyse the biomarkers related to MPE in NSCLC. <bold>Methods:</bold> We included patients with a metastatic NSCLC diagnosis who underwent a molecular analysis between 2018-2022. We analysed the biomarkers with targeted therapies approved by FDA at the moment of the study. We used multivariate logistic regression to determine the predictors of results. <bold>Results:</bold> 400 cases were included, 70,5% men, 67,3±10,7 years old. 75,8% patients were smokers. 52,8% expressed any biomarker, being PDL1 the most frequent(34,8%). 29% of cases presented MPE. No significant difference was found in the expression of EGFR between groups(18,1%vs13,4%,p=0,3). Biomarkers expression made no difference in patients with MPE related to clinical-demographical characteristics and oncological treatments. They presented similar mortality rate and worse ECOG (Table 1). Multivariate analysis indicates younger patients (OR:0,962;IC95% 0,939-0,985), pleural thickness (OR:14,994;IC95% 4,731-47,521), and ECOG < 1 (OR:0,539;IC95% 0,322-0,902) as independent factors associated with MPE <bold>Conclusion:</bold> Although there is a tendency of EGFR expression to be more present in MPE cases, MPE was not associated with any particular biomarkers. MPE patients were older and more symptomatic, which was related to a higher mortality.