Accurate staging of the mediastinum is essential to evaluate prognosis in non-small cell lung cancer and to devise an appropriate treatment plan. Mediastinal staging by surgical techniques (mainly cervical mediastinoscopy) is considered to be the gold standard, although surgical staging is invasive, requires general anesthesia, and is subject to potential serious complications. Endobronchial ultrasound (EBUS)-transbronchial needle aspiration (TBNA) is a new modality for the evaluation of mediastinal and hilar lymph node metastasis from lung cancer. Compared to other diagnostic methods, EBUS-TBNA is a real-time procedure that enables multiple biopsies with high-quality histologic cores under local anesthesia. However, there have been few data on the head-to-head comparisons of mediastinoscopy and EBUS-TBNA. The aim of this prospective study is to determine the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of EBUS-TBNA and mediastinoscopy in identifying N2 and N3 lymph node for patients with non-small cell lung cancer.

Inclusion Criteria:

• Histology-proven non-small cell lung cancer
• N2 or N3 lymph node invasion is suspected based on chest CT or PET/CT scans (at least one of three criteria) : 1) enlarged (1cm or more in short axis diameter) mediastinal lymph node(s), 2) FDG uptake in the mediastinal lymph node(s), or 3) FDG uptake in N1 node(s)
• The patient is otherwise considered a candidate for a surgical treatment with the intention to cure

Exclusion Criteria:

• Distant metastasis
• Inoperable T4 disease
• Confirmed supraclavicular lymph node metastasis
• Former therapy (chemotherapy or radiotherapy or surgery) for lung cancer
• Contraindications for bronchoscopy
• Uncorrected coagulopathy
• Concurrent other malignancies
• Suspicious mediastinal lymph node metastasis which are not accessible by EBUS-TBNA or mediastinoscopy (i.e. paraaortic, aortopulmonary window, or paraesophageal lymph nodes)