CT Scans of Smokers Cut Lung Cancer Deaths by 20%
Nov. 4, 2010 — Low-dose helical computed tomography (CT) scans beat out standard chest X-rays in reducing lung cancer deaths in smokers and past smokers. That’s according to the initial results of a large-scale government study on lung cancer screening released today.
”There was a 20% reduction in lung cancer mortality when you compared CT to X-ray,” says Constantine Gatsonis, PhD, a lead statistician in the analysis for the study and a professor of biostatistics at Brown University in Providence, R.I.
Sponsored by the National Cancer Institute, the National Lung Screening Trial (NLST) was halted early after the trial’s independent Data and Safety Monitoring Board notified the NCI that the data accumulating made it clear that the CT technology for lung cancer screening was superior to the standard X-ray in reducing deaths from lung cancer.
A letter dated Nov. 4 was sent to inform the more than 53,000 trial participants, all current or former heavy smokers aged 55 to 74, of the results.
“I would classify it as moderate,” Christine Berg, MD, NLST, project officer for the Lung Screening Study at NCI, says of the 20% reduction.
Even so, she tells WebMD, medical organizations that issue screening guidelines are expected to “take this information very seriously.”
Currently, she says, no major medical organizations that typically suggest screening guidelines for primary health care providers have issued recommendations for heavy smokers who don’t have symptoms of lung cancer.
More than 222,000 people in the U.S. are expected to be diagnosed with lung cancer and cancer of the bronchus this year, according to the NCI, with 157,300 deaths expected.
More than 94 million current and former smokers in the U.S. are at high risk for lung cancer, the NCI says.
A Visual Guide to Lung Cancer
Lung Cancer Screening: Trial Details
Chest X-ray and low-dose helical CT scans (also called spiral CT) have both been used to find lung cancer early. But in the NLST, investigators were looking at which way of detecting lung cancer reduced death rates more.
The trial, launched in 2002, examined more than 53,000 former or current heavy smokers who had a history of at least 30 ”pack-years” but no symptoms or signs of lung cancer when they entered the trial.
Pack-years are computed by multiplying the average number of packs of cigarettes smoked per day by the number of years a person has smoked. A person who smokes a pack a day for 30 years, for instance, or 2 packs for 15 years, has a 30 pack-year history.
Participants were assigned randomly to either a low-dose helical CT or standard chest X-ray group and were given the same test annually for three years.
Lung Cancer Screening: Trial Results
When the researchers analyzed the results to date in late October, they found that the benefit of CT scans was clear.