Using CT Scans to Screen Smokers Can Reduce Lung Cancer Deaths
Although lung cancer claims about 160,000 lives each year, there isn’t an effective screening method available to catch tumors early when they are more treatable. A new study announced by the National Cancer Institute may change that. The organization states that annual CT scans of current and former smokers may catch early cancers and reduce the risk of death by 20%.
CT Scans Could Catch Lung Cancers Earlier than X-Rays
CT scans use coordinated low-dose X-rays to provide a three-dimensional view of body tissues. The scans have been shown to detect lung tumors even at early stages.
The National Lung Screening Trial involved more than 53,000 current and former heavy smokers (30-pack years) between the ages of 55 and 74 without a diagnosis or signs of lung cancer. The participants were given either a standard chest x-ray or a CT scan at the start of the trial and then twice more over the next two years. Follow-up on outcome was conducted after five years.
As of October 20, 2010, there were a total of 354 deaths from lung cancer in the CT group compared with 442 in the chest x-ray group, representing a 20.3% reduction in lung cancer mortality.
The CT group also appeared to have a reduce risk of death from other causes as well. “Low-dose CT scan gives information on cardiovascular disease, emphysema, and other pulmonary diseases,” said Dr. Claudia Henschke MD PhD, of the Weill Cornell Medical Center in New York. “Those are the three big killers of older people.”
While the results are promising, there are quite a few drawbacks to recommending lung cancer screening by CT scan. Since there are more than 80 million current and former smokers in the United States, a widespread screening program would be costly. In addition, even low-dose CT scans expose patients to more radiation than standard chest X-rays, and the cumulative risks from years of scans are unknown.
The scans also produced a large number of false positives – non-cancer nodules and abnormalities were detected in one in four high-risk patients – leading to further, unnecessary testing.
And currently insurance companies do not pay for lung screenings, although Medicare plans to review the study results, says the National Cancer Institute director Dr. Harold Varmus.