Lung cancer screening with low-dose CT: a world-wide view

Lung cancer is the leading cause of cancer death worldwide, comprising almost 20% of all such deaths (1). The concept of using low-dose computed tomography (LDCT) to screen for lung cancer dates back almost three decades (2). Early observational studies on high-risk but asymptomatic subjects showed that LDCT detected more lung cancers than chest radiography, and that many of the detected cancers were early stage (3,4). The promising observational data led to the launching of several generally small randomized trials of LDCT screening, mainly in Europe (5-11). Additionally, they led to a definitive study in the USA, the National Lung Screening Trial (NLST), a randomized trial of over 50,000 high-risk current and former smokers comparing LDCT screening to screening with chest radiography (12). In 2011, the NLST reported a statistically significant 20% lung cancer mortality reduction in the LDCT arm (13)