Endobronchial ultrasound (EBUS) guided transbronchial needle aspiration (EBUS-TBNA) is an excellent tool for sampling enlarged mediastinal and hilar lymph nodes, but only provides needle aspirate samples which are often adequate for cytological examination only. More advanced histopathological and immunocytopathological assessment of tissue samples, which is particularly important in the diagnosis and staging of cancer, is often not possible with the small cellular samples obtained by EBUS-TBNA. A new transbronchial nodal aspiration needle (the Flex 19G EBUS-TBNA needle) has been developed with a larger needle diameter and more flexibility at the distal end, allowing better access to some lymph nodes stations. This needle can be passed down an EBUS scope and can hypothetically circumvent the deficiencies of EBUS-TBNA highlighted above by providing tissue adequate for histological assessment rather than cytological assessment alone.

This study aims to establish whether the use of the Flex 19G EBUS-TBNA needle can improve the diagnostic yield of EBUS sampling procedures compared to the use of the conventional TBNA needle, thereby allowing more accurate diagnoses and reducing the need repeat procedures or more invasive surgical biopsies, without causing an increase in complication rates. Patients with enlarged mediastinal and hilar lymph nodes referred for EBUS-TBNA will be randomised to have their nodes sampled by either the EBUS-TBNA needle (conventional procedure) or the novel Flex 19G EBUS-TBNA needle. The investigators hope to recruit 250 patients over a 24 month period.

Inclusion Criteria:

• Scheduled for EBUS-TBNA as part of clinical care
• Lymph nodes larger than 10mm in diameter
• Age > 18 years
• Written informed consent

Exclusion Criteria:

• Contraindication to needle biopsy (e.g. coagulopathy, anticoagulation, thrombocytopenia)
• Inability to obtain informed consent