Endoscopic ultrasound evaluation in the diagnosis and staging of lung cancer

The detection of mediastinal lymph node metastases in patients with lung cancer is most important. These nodes may be used for tissue diagnosis of the malignancy, if sampling techniques of the primary have failed. Their presence implies a stage III disease and may exclude a patient from surgery. CT is the standard imaging, but is relatively poor at staging the mediastinum (overall sensitivity: 50-70%), and is especially unreliable for lesions <1 cm. PET is a new physiological imaging technique, which seems to be superior to CT (sensitivity: 67-100%). Transesophageal EUS delivers high resolution imaging, offers the advantage of simultaneous tissue sampling (EUS-FNA sensitivity: 84-94%), but is limited to the posterior mediastinum. This review compares the diagnostic value of CT, PET and EUS as well as the different tissue sampling methods for mediastinal metastases with EUS-FNA. The technique of EUS and FNA is described, and a special interest is taken to stress out the different areas of the mediastinum accessible for each of the tissue sampling methods as well as the pros and cons for its use. Advantages and disadvantages of EUS-FNA are shown and the new efforts described to improve the outcome of EUS-FNA by adding molecular methods for the detection of micrometastases.