Lung cancer screening: latest developments and unanswered questions.

The US National Lung Screening Trial showed that individuals randomly assigned to screening with low-dose CT scans had 20% lower lung cancer mortality than did those screened with conventional chest radiography. On the basis of a review of the literature and a modelling study, the US Preventive Services Task Force recommends annual screening for lung cancer for individuals aged 55-80 years who have a 30 pack-year smoking history and either currently smoke or quit smoking within the past 15 years. However, the balance between benefits and harms of lung cancer screening is still greatly debated. The large number of false-positive results and the potential for overdiagnosis are causes for concern. Some investigators suggest the ratio between benefits and harms could be improved through various means. Nevertheless, many questions remain with regard to the implementation of lung cancer screening. This paper highlights the latest developments in CT lung cancer screening and provides an overview of the main unanswered questions.