Discrepancy of epidermal growth factor receptor mutation in lung adenocarcinoma presenting as multiple ground-glass opacities

OBJECTIVES: To identify epidermal growth factor receptor (EGFR) mutation status between different lesions in lung adenocarcinoma presenting as multiple ground-glass opacity (GGO) lesions and analyse its association with clinical characteristics. METHODS: Seventy-eight patients with lung adenocarcinoma presenting as multiple GGO lesions were identified to investigate EGFR mutation in exon 18-21. Lesions with the largest size in diameter were defined as the primary lesions; the others were defined as the secondary lesions. One hundred and fifty-nine lesions of these patients were classified into pure GGO and mixed GGO by computed tomography scan images. RESULTS: The EGFR mutation rate in the patients was 48.7% (38 of 78). Patients with high frequency of EGFR mutation were females and non-smokers. The EGFR mutation rate of invasive adenocarcinoma was higher than that of atypical adenomatous hyperplasia/adenocarcinoma in situ and minimally invasive adenocarcinoma (P = 0.001). Although 19-deletion and L858R were the most common EGFR mutations, there was no difference of EGFR mutation in pathological subtypes of adenocarcinoma. Of the 38 paired lesions in patients harbouring EGFR mutation, the discordance rate of EGFR mutation was 92.1%. CONCLUSIONS: The study showed different EGFR mutational profiles in multiple GGO lesions, suggesting that lesions seem to arise as independent events. It would offer useful information for determining the appropriate treatment strategy for lung adenocarcinoma presenting as multiple GGO lesions.