EBUS-TBNA for the diagnosis and staging of lung cancer

Introductiuon Non-small cell lung cancer (NSCLC) usually metastasizes first to hilar and mediastinal lymph nodes. Subsequently, hematogenous metastasis to distant sites may occur. Because survival is inversely correlated with stage, a meticulous staging procedure is required to determine the treatment and prognosis [ 1 ] [ 2 ]. For staging of NSCLC, the TNM classification has been developed, in which T stands for local tumor extension, N for lymph node metastasis, and M for distant metastasis. The lymph node map by Mountain et al., and its revisions are often used for the description of the N factor of the TNM classification [ 3 ]. Mediastinal lymph node staging can be divided into imaging and sampling. Computed tomography (CT), magnetic resonance imaging (MRI), and positron emission tomography (PET) may be used to image mediastinal lymph nodes [ 4 ]. Pathologic sampling of suspicious lesions can be performed by mediastinoscopy, thoracoscopy, transthoracic fine-needle aspiration, transbronchial fine-needle aspiration, and endoscopic ultrasonography with fine-needle aspiration [ 4 ] [ 5 ]. For many years mediastinoscopy has been regarded as the ‘gold standard’ for staging of the mediastinum but it is invasive, requires a general anaesthetic and is costly. While a standard cervical mediastinoscopy permits access to paratracheal lymph node stations (levels 2R, 2L, 4R and 4L) and the anterior subcarinal lymph node station (level 7), access to the posterior and inferior mediastinum is limited and requires either extended cervical mediastinoscopy or a thoracoscopy [ 6 ]. Since 2004 a novel prototype linear array endobronchial ultrasound (EBUS) probe with a fine needle biopsy facility for real-time imaging and aspiration biopsy of paratracheal and parabronchial lymph nodes (stations 2, 3, 4, 7, 10 and 11) is available. With this scope direct TBNA under real time convex probe endobronchial ultrasonography (EBUS-TBNA-bronchoscopy) guidance is now possible.