Image-guided fine needle aspirate strategies for staging of lung cancer

Image-guided transthoracic, bronchoscopic, and endoscopic ultrasound fine needle aspiration (FNA) greatly facilitates lung cancer staging by having the potential to precisely biopsy lung lesions and virtually all mediastinal lymph node stations. Imaging modalities alone, including chest x-ray, computed tomography (CT), magnetic resonance imaging, and positron emission tomography identify lesions suspicious for cancer but cannot make a tissue diagnosis. We describe an algorithm for the diagnosis and tumor-node-metastasis staging of lung cancer that uses procedures with the least invasiveness and cost with the highest diagnostic yields. For the anterior mediastinum, fluoroscopic-, ultrasound-, or CT-guided transthoracic FNA (which has a greater yield than bronchoscopy and is less invasive than mediastinoscopy) should be the primary technique for lymph node sampling. In the middle mediastinum, CT-guided transthoracic FNA is preferred for all nodal stations except subcarinal. Endoscopic ultrasound-guided FNA (EUS-FNA), which enables real-time biopsies within 5 cm of the esophagus, is preferred for sampling subcarinal and posterior mediastinal nodes because the yield is similar to CT-guided transthoracic FNA, with minimal risk of pneumothorax. The posterior mediastinum is also accessed by fluoroscopic- or CT-guided transthoracic FNA or video-assisted thoracic surgery. Sampling of the aorticopulmonary window depends on lymph node size; if the nodes are large enough to displace the aortic arch and pulmonary vein, then EUS-FNA is attempted, and if the nodes are not sufficiently enlarged, CT-guided transthoracic FNA should be performed prior to thoracoscopy or thoracotomy.