Exploring novel, minimally invasive, multi-modal bronchoscopic biopsy tools and techniques using radial endobronchial ultrasound and the guide sheath to improve the diagnostic yield of peripheral pulmonary lesions suspected of lung cancer

Abstract

Peripheral pulmonary lesions (PPL) suspected of lung cancer require a safe, high-yield diagnostic biopsy with concurrent mediastinal staging to reduce treatment delays. Emerging lung cancer screening programmes amplify this need. Radial EBUS is a safe bronchoscopy biopsy method for PPL, but the diagnostic yield is low. This thesis hypothesised that it was possible to improve the yield with novel biopsy tools and techniques. Four multi-centre interventional studies were performed. The novel biopsy tools (cryobiopsy and GenCut tool) were examined, and existing biopsy tools (guide sheath and aspiration needle) were optimised and combined as a multi-modal biopsy. This thesis consists of the first published head-to-head comparison of multi-modal Cryo-Radial biopsy against percutaneous CT-guided biopsy (CT-TTB) for PPL: a study compromised by slow recruitment that resulted in its early termination. Available data showed a modestly lower diagnostic yield than CT-TTB, but significantly fewer critical adverse events, pneumothorax, or haemorrhage. Bronchoscopic cryobiopsy was introduced to tertiary hospitals in New Zealand, for the first time, through this study in 2015 with relevant safety precautions. To cater for centres where cryobiopsy was not widely available but a core tissue sample was required, a novel GenCut tool was explored as an alternative suitable for sedation bronchoscopy. A multi-modal biopsy approach, rather than reliance on forceps alone, improved the diagnostic yield with adequate tissue obtained for critical molecular testing. This concept of multi-modal biopsy was not reported in Radial EBUS literature at the time of these studies in 2015. The addition of these safe diagnostic techniques will allow rapid, personalised diagnostic pathways for patients with suspected lung cancer.