The National Lung Screening Trial (NLST) compared low-dose computed tomography (CT) screening with chest radiography to determine if screening could reduce lung cancer mortality. Over 53,454 high-risk participants were enrolled at 33 U.S. medical centers, with 26,722 assigned to low-dose CT and 26,732 to chest radiography. More than 90% adhered to screening, with 24.2% of low-dose CT tests and 6.9% of radiography tests being positive. Over 94% of positive results were false positives. The incidence of lung cancer was higher in the low-dose CT group (645 per 100,000 person-years) compared to radiography (572 per 100,000 person-years), with a 20% relative reduction in lung cancer mortality in the low-dose CT group. The rate of death from any cause was also reduced by 6.7% in the low-dose CT group. The study concluded that low-dose CT screening reduces lung cancer mortality. The trial was funded by the National Cancer Institute and followed strict protocols for data collection and analysis. The results showed that low-dose CT detected more early-stage cancers and had a higher rate of false positives, but the overall mortality reduction was significant. The study also noted potential harms, including overdiagnosis and radiation-induced cancers, which require further research. The NLST findings support the use of low-dose CT for lung cancer screening, but further studies are needed to assess long-term benefits and risks. The trial was conducted with rigorous oversight and data monitoring, and its results have influenced current guidelines for lung cancer screening.The National Lung Screening Trial (NLST) compared low-dose computed tomography (CT) screening with chest radiography to determine if screening could reduce lung cancer mortality. Over 53,454 high-risk participants were enrolled at 33 U.S. medical centers, with 26,722 assigned to low-dose CT and 26,732 to chest radiography. More than 90% adhered to screening, with 24.2% of low-dose CT tests and 6.9% of radiography tests being positive. Over 94% of positive results were false positives. The incidence of lung cancer was higher in the low-dose CT group (645 per 100,000 person-years) compared to radiography (572 per 100,000 person-years), with a 20% relative reduction in lung cancer mortality in the low-dose CT group. The rate of death from any cause was also reduced by 6.7% in the low-dose CT group. The study concluded that low-dose CT screening reduces lung cancer mortality. The trial was funded by the National Cancer Institute and followed strict protocols for data collection and analysis. The results showed that low-dose CT detected more early-stage cancers and had a higher rate of false positives, but the overall mortality reduction was significant. The study also noted potential harms, including overdiagnosis and radiation-induced cancers, which require further research. The NLST findings support the use of low-dose CT for lung cancer screening, but further studies are needed to assess long-term benefits and risks. The trial was conducted with rigorous oversight and data monitoring, and its results have influenced current guidelines for lung cancer screening.