Screening With Low-Dose CT Scan Reduces Deaths From Lung Cancer

The New England Journal of Medicine today released results of a study showing that patients screened with low-dose helical computed tomography (CT) reduced their risk of dying of lung cancer by 20% compared with chest x-ray.

From August 2002 through April 2004, the National Lung Screening Trial (NLST) enrolled 53,454 people at 33 cancer centers in the United States who were at high risk for lung cancer. All enrollees were aged 55 to 74 years and had at least a 30 pack-year history of smoking. Although patients did not need to be current smokers, they must have stopped smoking within the previous 15 years. Those with a previous diagnosis of lung cancer, hemoptysis, or an unexplained weight loss >15 pounds in the preceding year were excluded.

The participants were assigned to receive 3 annual screening exams with either low-dose CT (n = 26,722) or single-view posteroanterior chest radiography (n = 26,732) and were followed through December 31, 2009.

Over all 3 screening rounds, there were 24.2% positive screenings detected with low-dose CT and 6.9% positive screenings with radiography. Of those positive screenings, 96.4% of those in the low-dose CT group and 94.5% in the radiography group were false positives. There were a total of 1060 cancers in the low-dose CT group compared with 941 cancers in the radiography group (rate ratio, 1.13; 95% confidence interval [CI], 1.03-1.23).

Outcome data show that in low-dose CT group, 356 patients died from lung cancer whereas 443 patients in the radiography group died from lung cancer—a mortality reduction risk of 20% in the low-dose CT group. As for overall mortality, 1877 patients in the low-dose CT arm died during the 7-year study period compared with 2000 in the radiography group. The study results represent a 6.7% reduction in the rate of death from any cause with low-dose CT (P = .02) and a 20% reduction in the rate of death from lung cancer (P = .004).

The National Lung Screening Trial Research Team. Reduced lung-cancer mortality with low-dose computed tomographic screening. N Engl J Med [published online ahead of print June 29, 2011]. doi:10.1056/NEJMoa1102873.