Current advances of endobronchial ultrasonography in the diagnosis and staging of lung cancer

Lung cancer is the leading cause of cancer related death (1). The prognosis for lung cancer is extremely poor and a five year survival rate remains less than 15% (2). Two-thirds of patients had advanced disease when they were diagnosed (1,3). The factors that affect prognosis in patients with lung cancer are stage, histology, performance status, comorbidity, age and sex (4). Before the introduction of novel cytotoxic chemotherapy (pemetrexed) and biologic agents (bevacizumab), the main diagnostic modalities and focus on tissue acquisition were obtaining small samples for simple histopathological characterization: small cell lung cancer (SCLC) vs. non-small cell lung cancer (NSCLC) (5,6). Markers to differentiate between adenocarcinoma and squamous cell carcinoma are now necessary and are defined by the 2011 International Association for the Study of Lung Cancer/American Thoracic Society/European Respiratory Society (IASLC/ATS/ERS) lung adenocarcinoma classification (7). Adenocarcinoma can also be classified according to the driver oncogene mutation that is present, which is usually mutually exclusive in the different subtypes (8). The current guidelines suggest molecular testing for EGFR and ALK after adenocarcinoma has been confirmed. Therefore, sufficient and high quality tissue for diagnosis, and molecular testing for treatment selection become important