CT less effective preventing low-risk lung cancer mortality
CT Screens Prevent Few Deaths in Those at Low Risk of Lung Cancer
(HealthDay News) -- The relatively greatest number of deaths from lung cancer is prevented when screening with low-dose computed tomography (CT) is targeted to those at highest risk, according to research published in the July 18 issue of the New England Journal of Medicine.
Stephanie A. Kovalchik, Ph.D., of the National Institutes of Health in Bethesda, Md., and colleagues analyzed data from the previously completed National Lung Screening Trial to assess the association between lung-cancer risk and the benefit of screening in 26,604 participants who underwent low-dose CT screening and 26,554 participants who underwent chest radiography. The five-year risk of lung-cancer death ranged from 0.15 to 0.55 percent in the lowest-risk group (quintile 1) to greater than 2.00 percent in the highest-risk group (quintile 5).
The researchers found that the number of lung-cancer deaths per 10,000 person-years that were prevented in the CT-screening group compared with the radiography group showed a significant increasing trend of 0.2, 3.5, 5.1, 11.0, and 12.1 across quintiles 1 through 5, respectively. The number of false-positive results per lung-cancer death prevented by screening showed a significant decreasing trend of 1,648, 181, 147, 64, and 65 across quintiles 1 through 5, respectively. Among the 60 percent of participants who were at the highest risk for lung-cancer death (quintiles 3 through 5), 88 percent of the screening-prevented lung-cancer deaths and 64 percent of the false-positive results occurred. Among the 20 percent of participants who were at the lowest risk for lung-cancer death (quintile 1), only 1 percent of the screening-prevented lung-cancer deaths occurred.
"Screening with low-dose CT prevented the greatest number of deaths from lung cancer among participants who were at highest risk and prevented very few deaths among those at lowest risk," the authors write. "These findings provide empirical support for risk-based targeting of smokers for such screening."