The role of endobronchial ultrasound-guided transbronchial needle aspiration in the diagnosis of mediastinal lymphadenopathy

Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) is a novel procedure for the diagnosis of mediastinal lymphadenopathy. Its utility in clinical practice for the diagnosis of patients presenting with mediastinal lymphadenopathy is unknown. This thesis describes the learning curve associated with EBUS-TBNA using cumulative sum analysis and then the diagnostic yield of EBUS-TBNA in different clinical scenarios. EBUS-TBNA was combined with standard bronchoscopy in patients with suspected sarcoidosis in a prospective trial. The role of EBUS-TBNA in patients with tuberculous lymphadenopathy and also patients with extra-thoracic malignancy was then clarified in multi-centre studies. A further prospective trial (REMEDY) aimed to ascertain whether mediastinoscopies could be prevented in patients presenting with isolated mediastinal lymphadenopathy. The utility of the specimens from EBUS-TBNA for sub-typing and genotyping of non-small cell lung cancer are also described in a multi-centre study. Finally, the results from a major multi-centre randomised controlled trial (Lung-BOOST) are presented, investigating whether EBUS-TBNA should be implemented as a first test in patients with suspected lung cancer. The data included in this thesis demonstrate that EBUS-TBNA has high diagnostic yield in patients with sarcoidosis, tuberculosis and extra-thoracic malignancy. For the first time, the REMEDY trial demonstrates that EBUS-TBNA can prevent 87% of mediastinoscopies in patients with isolated mediastinal lymphadenopathy. In patients with lung cancer, specimens from EBUS-TBNA are suitable for sub-typing and genotyping of NSCLC and results from the randomised Lung-BOOST trial demonstrate that when EBUS-TBNA is used as an initial investigation in patients with suspected lung cancer the time to treatment decision is significantly reduced.