The Importance of EGFR Mutation Detection Method for the Correct Clinical Management of Patients with Non-Small Cell Lung Cancer: A Case Report

Abstract

In patients with non-small cell lung cancer (NSCLC), the naive double EGFR mutation of exon 18 represents an unusual event and the few papers in the literature demonstrated the attenuated response to different tyrosine kinase inhibitors (TKIs). We presented a case of a 73-year-old female smoker patient with adenocarcinoma in the right upper lung lobe diagnosed in another Italian Hospital Center and the first molecular analysis, performed by the pyrosequencing platform in a cytological smear, identified a G719A mutation of EGFR gene. The patient was immediately treated with afatinib at a daily dose of 40 mg as TKI. During the normal follow up it was noted a partial response (PR) to treatment and, a new Computer Tomography, revealed the presence of an abnormal shadow in the right lower lung. A new Transbronchial Needle Aspiration (TBNA) and the consequent cyto-histological diagnosis revealed a relapse of the disease. A new molecular analysis made in our Center with Sequenom platform, showed a double EGFR mutation (G719A+E709A), both of exon 18. We also tested the EGFR with Sequenom platform in the cytological smear used for the first diagnosis, kindly sent us by Pathological Anatomy Unit of the Hospital Center, revealing both the double EGFR mutation G719A+E709A. Therefore, both mutations were the naive double EGFR mutation of exon 18. This result explained the PR to afatinib treatment and highlighted the importance of multiplex and sensitive methods used to identify the correct EGFR activating mutations in NSCLC, on the right clinical management of these patients.