Mediastinal Staging of Non-Small-Cell Lung Cancer

Christian Lloyd, MD, and Gerard A. Silvestri, MD, FCCP, Division of Pulmonary and Critical Care Medicine at the Medical University of South Carolina, Charleston.

Cancer Control. 2001;8(4) 

In This Article

Endoscopic Ultrasound-Guided Mediastinal Lymph Node Aspiration

One of the most exciting developments in the staging of the mediastinum has been the development of transesophageal endoscopic ultrasonographic guidance for fine-needle aspiration (EUS/FNA) of mediastinal lymph nodes. Initially developed to study echo features of gastrointestinal malignancies, EUS has become the study of choice for defining local tumor and lymph node staging of gastrointestinal tumors. Esophageal EUS provides accurate images of the entire posterior mediastinum, including lymph nodes in the subcarinal,aortopulmonary, and paraesophageal regions. This has led to studies of its diagnostic accuracy for mediastinal malignancy. In an early study[41] examining mediastinal malignancies, EUS echo features had an accuracy of 84% compared with 49% for conventional CT. The development of echo endoscopes capable of imaging parallel to the long axis of the scope made EUS-guided intervention possible. Lymph nodes in the subcarinal, aortopulmonary, and paraesophageal regions and along the pulmonary ligament can be sampled.

Intense research currently is ongoing in this area.Silvestri and colleagues[29] used EUS to examine [27] patients with known or suspected lung cancer. Of these patients, 22 had enlarged lymph nodes on CT. Overall, 16 patients had positive findings on EUS with 15 positive fine-needle aspirates, and one patient had T4 disease not seen on CT. Of the 11 patients with negative biopsies, two had micrometastatic disease to the lymph node at surgery. In a study of patients who had unsuccessful bronchoscopic workup of presumed lung cancer, Fritscher-Ravens et al[42] established a diagnosis of malignancy in 25 of 35 patients. The overall sensitivity of the procedure was 96%. In 7 patients, the punctured nodes were less than 1 cm, making them difficult to biopsy by other means. No complications were seen in this study.

Advantages of EUS over surgery include lower cost and lower morbidity. It can be performed under standard esophagogastroduodenoscopy (EGD) conditions,including conscious sedation. It can be used to biopsy lymph node levels that are inaccessible or difficult to access by mediastinoscopy, including the para-aortic and paraesophageal regions. Its advantages over conventional TBNA include the ability to visualize and biopsy nodes less than 1 cm with seemingly good accuracy. Disadvantages include the inability to biopsy right paratracheal and pretracheal nodes due to the air-filled trachea,which blocks the ultrasound signal. Also, EUS is presently available in only a few major medical centers.

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