Comparative study of EGFR mutations detected in malignant pleural effusion, plasma and tumor tissue in patients with adenocarcinoma of the lung.

OBJECTIVES

The utility of malignant pleural effusion (MPE) as a source for determining EGFR mutations to guide EGFR TKI therapy in advanced adenocarcinoma of the lung remains unclear. This study compared MPE, plasma and tumor tissues as sources of biological samples for EFGR mutational analysis of lung adenocarcinoma patients.

MATERIALS AND METHODS

Total 295 MPE samples were retrospectively collected from lung adenocarcinoma patients. Matched tissue and plasma samples were available for 92 patients, and 248 patients had plasma samples. EGFR exon-19-deletion and exon 21-L858R mutation were detected with Denaturing high performance liquid chromatography (DHPLC). The concordance of EGFR mutation status in MPE, tissue, and plasma were evaluated, and the value of EGFR mutations in MPE with respect to efficacy of EGFR-TKI was investigated.

RESULTS

The EGFR mutation rate in MPE samples was 39.3% (116/295). The concordance between MPEs and tissues was 87.1% (Kappa = 0.71); the sensitivity and specificity of EGFR mutation in MPEs according to tissues was 71.4% and 96.5%, respectively. And 219 patients received EGFR-TKI, and the objective response rate was similar for patients with EGFR mutation either in MPE, tissues or plasma (57.6% vs 56.0% vs 47.4%, p = 0.51). Similar results were found in progression free survival (8.9 months vs 9.0 months vs 7.7 months, p = 0.077 and overall survival (29.8 months vs 25.9 months vs 25.3 months, p = 0.33).

CONCLUSION

MPE is a reliable surrogate for tumor tissue for identifyingEGFR mutations. MPE could offer reference of EGFR mutation to EGFR-TKIs treatment decision for advanced lung adenocarcinoma patients even when tissue and plasma were available.