The National Lung Screening Trial (NLST) made headlines across the world last November by showing that a screening program cut lung cancer deaths by 20 percent in a high-risk population. The University of Minnesota provided the largest number of participants—about 6,600—in the national study, which included 54,000 current or former heavy smokers aged 55 to 74.
Participants received either standard chest X-rays or low-dose helical computed tomography (CT) scans annually for three years.
Helical CT, also called spiral CT, uses X-rays to obtain a multiple-image scan of the chest and can detect smaller tumors than standard chest X-rays can.
Led by principal investigator Timothy Church, Ph.D., a Masonic Cancer Center member, the researchers followed both groups for five more years to see whether the screening detected lung cancer early enough to reduce mortality. They documented 20 percent fewer lung cancer deaths among participants screened with the CT scans compared with those screened with X-rays.
“This is a landmark finding,” says Church, a professor in the School of Public Health. “Our participants should be proud of the enormous contribution they have made to the well-being of their fellow humans and to proving another tool in the fight against lung cancer, the biggest cancer killer in the United States and the world.”
A more complete analysis will be prepared for publication later this year. In the meantime, the National Cancer Institute, which sponsored the NLST, cautions the public not to extrapolate the results to the general population. In peopleat lower risk of lung cancer than the trial participants, the potential harms from radiation exposure could outweigh the benefits of screening.