Rationale: Lung cancer is the most commonly diagnosed cancer worldwide and is the most frequent cause of cancer death. Accurate staging is important because it directs treatment and prognosis. Mediastinal staging can be done by both EBUS-TBNA and EUS-FNA. These two techniques have a complementary diagnostic range and the combined procedure is suited for assessment of almost the entire mediastinum. In practice, when mediastinal tissue staging is indicated, endoscopists often perform either an EBUS or an EUS investigation (instead of the combined procedure). Second, frequently only one or two, by imaging suspected lymph node stations, are sampled (ie. targeted approach).

Objectives: main and secondary:

1. Complete endosonographic (combined endobronchial and esophageal) staging using a single EBUS scope improves locoregional staging (N2, N3, T4) versus EBUS staging alone.
2. Systematic mediastinal staging results in improved locoregional staging compared to PET-CT directed assessment of the mediastinum (ie targeted approach).

Study population: Patients with potentially operable and resectable NSCLC are eligible if there is an indication for mediastinal nodal sampling. Patients have an indication for EBUS-TBNA.

Intervention: Patients will undergo an EBUS investigation followed by EUS-B in the same session. During this single scope procedure, lymph nodes that are suspected on prior CT-PET imaging and on subsequent ultrasound are sampled.

Main study endpoint: The main study parameter is the sensitivity for locoregional disease (N2, N3, T4 disease) of complete endosonographic staging (by EBUS-TBNA and EUS-B-FNA) in comparison with EBUS staging alone.

Inclusion Criteria:

• (Suspected) NSCLC;
• Indication for mediastinal nodal assessment;
• Suspected mediastinal lymph nodes within reach of EBUS;
• Age 18 years or older;
• Clinically fit to undergo surgical resection of the lung tumor;
• Provision of a written informed consent;

Exclusion Criteria:

• Mediastinal re-staging after neo-adjuvant treatment;
• Indication for EUS other than mediastinal staging, eg a for malignancy
• suspected left adrenal;
• Active malignancy with a life expectancy of less than two years;
• Former therapy for lung cancer (chemotherapy, radiotherapy or surgery);
• Technical contraindication for EBUS or EUS (eg, esophagus stenosis);
• Pregnancy;
• Inability to consent;

Patients with potentially operable and resectable NSCLC are eligible if there is an indication for mediastinal nodal sampling. Patients have an indication for EBUS-TBNA.