In the era of targeted therapy, the association between lung adenocarcinoma patient survival and malignant pleural effusions (MPEs) remains unclear. This study investigated the clinical characteristics, survival and epidermal growth factor receptor (EGFR) gene (EGFR) mutation status of lung adenocarcinoma patients with MPE.

From June 2005 to December 2010, consecutive pleural effusions were collected prospectively. Patient clinical characteristics, EGFR mutation status, and overall survival were analysed.

We collected MPEs from 448 patients in stage IV lung adenocarcinoma at initial diagnosis. Median overall survival for patients with MPEs at initial diagnosis and following disease progression were 14.3 months and 21.4 months, respectively (p=0.001). There were 296 (66.1%) patients harbouring EGFR mutations, the mutation rates among patients with an MPE at initial diagnosis and one following disease progression were 68.2% and 56.6%, respectively (p=0.044); the L858R mutation rate was also higher among the former (32.6% versus 18.1%; p=0.009). Multivariate analysis revealed that patients who: developed MPEs following disease progression, harboured EGFR mutations, and received EGFR-tyrosine kinase inhibitor therapy, had longer overall survival. Patients in stage IV lung adenocarcinoma with MPEs at initial diagnosis have shorter overall survival and higher EGFR mutation rate, especially for L858R, than patients who develop MPEs following disease progression.