Screening for lung cancer using low-dose "spiral" CT scans reduces lung cancer mortality by 20 percent compared to screening with chest X-ray, the National Cancer Institute recently announced.

"For the first time there is evidence from a randomized prospective clinical trial that low dose screening chest CT results in a decrease in the number of deaths in people at high risk for lung cancer," said Kavita Garg, M.D., professor of radiology at the University of Colorado School of Medicine and University of Colorado Hospital. "We could save lives. It's just a matter of time until we get official guidelines for how best to use this tool."

The results come from the National Lung Screening Trial, a randomized national study involving more than 53,000 current and former heavy smokers ages 55 to 74. The NLST compared the effects to two screening procedures – low-dose helical computed tomography (CT) and standard chest X-ray – on lung cancer mortality and found 20 percent fewer lung cancer deaths among trial participants screened with low-dose CT. The study also showed a 7 percent overall decrease in death from all causes in those screened with CT.

The University of Colorado Cancer Center was among the largest of 30 trial sites, enrolling 3,743 Colorado smokers and former smokers who had a 30-plus pack year history of smoking. Participants were randomly selected for three annual lung cancer screenings using chest X-ray or low-dose CT scan, then were followed for five years. Garg was co-principal investigator for the Colorado arm of the trial.

Guidelines are forthcoming for how often people at high risk of lung cancer should be screened using low-dose CT, the NCI said. Until the data is further analyzed, University of Colorado doctors are cautious, yet optimistic, about recommending screening for high-risk people.

"This is good news for people at high risk for lung cancer, specifically those who have smoked heavily," said David Lynch, MBMD, professor of diagnostic radiology at the School of Medicine and National Jewish Health. He serves on the national NLST executive committee.

Lynch and Garg recommended that people who have smoked heavily talk to their personal physicians about whether they should undergo screening with low-dose CT. Medicare, Medicaid and private insurance companies do not cover the cost of screening CT scans today.

NCI also announced preliminary data from the Prostate, Lung, Colorectal and Ovarian Cancer screening trial that looked at people enrolled in that study who met the NLST criteria and were either screened for lung cancer using chest X-ray or not screened at all.

"The data indicates that there is no benefit in screening for lung cancer with chest X-ray compared to not screening at all," Lynch said. "That's a significant finding, because when you combine it with the NLST data, it means CT screening for lung cancer saves lives compared to not screening at all. That's never been shown before."