How should pulmonary nodules be optimally investigated and managed?

Pulmonary nodules are a common incidental finding on CT and the inexorable rise in the use of CT (10% increase per year in the UK over the last decade) means that the frequency of their detection is likely to increase over coming years. This may be augmented further if CT screening is implemented. Management has previously been influenced by North American guidelines, with the most widely used resource to date being the Fleischner Society guidelines published in 2005. These predominantly focus on the timing of CT scans arranged to survey small pulmonary nodules (≤ 8 mm), and the guideline authors chose not to offer specific recommendations regarding larger nodules. More recently, the society published specific guidelines for sub-solid nodules, reflecting the different prognosis that this subtype of nodules confers. The American College of Chest Physicians have published two guidelines on pulmonary nodules-the latest was completed in 2012 and published in Chest the following year. However, the investigation and management of pulmonary nodules is a rapidly evolving subject largely driven by evidence from the large CT screening studies. In 2012, The British Thoracic Society (BTS) convened a guideline development group to address the topic of pulmonary nodule investigation and management, with publication of the guideline in July 2015. One third of the 359 references included in the guideline date from 2012 onwards, and many of the differences between the recommendations made and previous guideline recommendations reflect this recent evidence. This article reviews specific evidence considered in formulating the BTS guidelines, and summarises the main guideline recommendations.