After decades of relatively unsuccessful attempts to improve survival for patients with lung cancer, CT screening has changed the scene. After publication of the results from a pioneering non-randomised pilot study, one large-scale randomised controlled trial in the USA and seven European randomised controlled trials were designed to investigate whether earlier detection of lung cancer—made possible primarily by following up after detection of a high quantity of CTvisible pulmonary nodules in high-risk people, which had not yet given rise to complaints—could be followed by earlier, more effective treatment. The results of the National Lung Screening Trial, which showed efficacy of CT screening, were used by the US Preventive Services Task Force and a consortium of modellers to assess whether a more advantageous strategy was possible than the one initially designed. Annual screening of individuals aged 55–80 years, who smoked 30 or more pack-years, and who had been regular smokers within the past 15 years, led to a very reasonable harm-to-benefit ratio. But are these limited criteria the best ones to use? [...]