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Low-Dose CT Screening for Lung Cancer Provides Greater Benefit for High-Risk Patients

Screening for lung cancer with low-dose computed tomography (CT) appears to only provide benefit to individuals who are at a high-risk of developing lung cancer. These results were recently published on-line in the New England Journal of Medicine.

The National Lung Screening Trial (NLST) demonstrated a significant improvement in survival among former smokers who were screened with low-dose CT, versus those who were screened with standard chest x-ray. The NLST included over 50,000 individuals who had a 30-pack year smoking history, but had quit smoking no later than 15 years prior to screening. Those screened with CT had a 20% reduced risk of death from lung cancer compared to those screened with chest x-rays. However, due to the expense, rate of false-positives and overall radiation exposure of the screening, researchers continue to explore exactly which individuals derive benefit from the screening.

Researchers recently evaluated data from NLST to better determine which variables were associated with a benefit from screening for lung cancer with low-dose CT.

88% of the prevented lung cancer deaths from screening came from individuals who were in the highest risk category for developing lung cancer.
Only 1% of the prevented lung cancer deaths from screening came from individuals who were in the lowest risk category for developing lung cancer.
CT scanning prevented fewer lung cancer deaths as the risk for developing lung cancer decreased.
The authors stated that “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. These findings provide empirical support for risk-based targeting of smokers for such screening.” Individuals who are former smokers or have other risk factors for developing lung cancer should speak with their healthcare provider regarding screening measures.

Reference: Kovalchik S, Tammemagi M, Berg C, et al. Targeting of low-dose CT screening according to the risk of lung-cancer death. New England Journal of Medicine. 2013; 369:245-254.