It is reported that more than 90,000 patients died of lung cancer and more than 20% of them were older than 80 years in North America. Therefore a less invasive but effective treatment is required for patients with lung cancer of advanced age, diminished pulmonary functions, and chronic diseases. Stereotactic body radiation therapy (SBRT) is an effective and well-tolerated treatment for early stage lung cancer in medically inoperable patients. On the other hand, accurate mediastinal and hilar lymph node staging is one of the most important factors that determine the outcome and indications for SBRT. Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) is a novel, minimally invasive modality that enables the assessment of mediastinal and hilar lymph nodes with a high sensitivity. Accurate lymph node staging by EBUS-TBNA will allow opportunities for high-risk patients with lung cancer to undergo minimally invasive treatment.

Patients with radiologically early stage lung cancer who are candidates for SBRT will be enrolled in this study. Prior to enrollment, patients are required to be evaluated by an experienced thoracic surgeon, radiation oncologist or medical oncologist to determine operability. Patients will udergo computed tomography (CT) and positron emission tomography (PET) prior to EBUS- TBNA. EBUS-TBNA will be performed at the Interventional Thoracic Surgery Suite (ITSS) located at Toronto General Hospital by a Thoracic Surgeon. The procedure will be performed under local anesthesia with conscious sedation. Mediastinal as well as hilar lymph nodes will be assessed by EBUS-TBNA. The result of pathological diagnosis using EBUS-TBNA will be compared with the result of radiological staging (CT and PET-CT). Patients who are negative for mediastinal lymph node metastasis by EBUS-TBNA will undergo SBRT. In addition, the treatment outcome will be evaluated based on the clinical chart review.

Inclusion Criteria:

1. Age 18 years or older
2. Patients with confirmed lung cancer who require EBUS-TBNA as part of their staging investigations of the mediastinum and hilum prior to SBRT
3. Performance status score (WHO/ECOG) of 0-2.
4. Cytological or histological proof of non-small cell cancer
5. Stage T1-2 disease, with no evidence of distant metastasis
6. Patients are screened by both computed tomography (CT) and positron emission tomography (PET)
7. Medically inoperable for surgical resection
8. Patients who refused surgery

Exclusion Criteria:

1. Patients who are deemed on clinical grounds not to be medically fit for a bronchoscopy
2. Active systemic, pulmonary, or pericardial infection
3. Patients who are pregnant or lactating
4. Patients with plans to receive conventional radiotherapy, chemotherapy, biological therapy, vaccine therapy, or surgery as treatment (except at disease progression).
5. Inability to give informed consent