EBUS-TBNA is often the sole diagnostic test applied in patients with stage IV lung cancer. A limitation of the TBNA needle when using a 22 Gauge needle is the limited ability to procure adequate histological samples. Although a larger 19 Ga needle can procure histological samples as demonstrated by the conventional 19 Ga needle, published data are not existing with respect to molecular diagnostics. A new nitinol-based 19 Ga needle has been developed for EBUS-TBNA. Given the frequent usage of 22 Ga needles for molecular diagnostics and the recent technical advancements in 19 Ga needle technology, we conduct a RCT to compare the performance of both needle types.

All patients with (suspected) stage IV lung carcinoma identified on spiral computed tomography scan and requiring an EBUS-TBNA investigation to obtain intrathoracic hilar or mediastinal lymph node tissue for diagnosis, subtyping and genotyping of lung cancer are eligible for participation in this study. Procedural technique : patients undergo an EBUS-TBNA procedure with either the Flex 19 Ga needle or the 22 Ga needle ; all procedures are performed using a linear array echoendosope under moderate sedation (standard practice). Primary endpoint of the study is the presence of core tissue that is defined as a continuous string of material as observed on the microscopic examination. Secondary endpoints are elements relevant to molecular analysis.

Inclusion Criteria:

• (suspected) stage IV lung carcinoma identified on spiral computed tomography scan
• requiring an EBUS-TBNA investigation to obtain intrathoracic hilar or mediastinal lymph node tissue for diagnosis

Exclusion Criteria:

• uncontrolled coagulopathy
• tracheal stenosis