CONTEXT: Lung cancer is the most common cancer in men and the leading cause of cancer death worldwide. This cancer, often diagnosed at an advanced stage, mainly affects smokers and survival could increase with early detection. Screening by chest x-ray has not shown its effectiveness, then several randomized trials have been carried out about screening by thoracic low-dose computed tomography in smokers. METHODS: A systematic review of these trials was conducted according to the PRISMA criteria as well as a point of the difficulties of setting up screening following these trials. RESULTS: Among five trials that published mortality results, only the US one, the National Lung Screening Trial (NLST) was showed a 20% decrease in lung cancer mortality in smokers screened by low-dose computed tomography compared to chest x-ray. However, besides the lack of power of the other trials, a great heterogeneity of the methods makes the synthesis of the results difficult. While many expert groups are in favor of testing, only the United States has implemented a screening program, whose adherence remains low. CONCLUSION: Many persistent questions about the eligible population, the organization, the side effects, and finally the cost-benefit, need additional research around these issues.Read less <