CT scans may decrease lung cancer mortalities
■ Twenty percent fewer deaths occur among current and former heavy smokers screened with low-dose CTs than with chest x-rays, a new study finds.
By Christine S. Moyer — Posted Nov. 24, 2010
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Low-dose computed tomography scans might help reduce lung cancer mortalities among heavy smokers and former smokers, according to a new report. But further analysis of the findings is needed before screening recommendations can be issued for the disease, said a statistician for the study.
There is no generally accepted screening test for lung cancer. The U.S. Preventive Services Task Force said evidence is insufficient to recommend for or against screening asymptomatic people for the disease with either low-dose CT scans, chest x-rays, sputum cytology or a combination of these tests.
Results of the study, which were published online Nov. 2 in Radiology, found that CT scans decreased the mortality rate of heavy smokers and former smokers by 20.3% compared with chest x-rays. The National Cancer Institute sponsored the study.
"For the first time, we have definite proof that screening for lung cancer can reduce mortality," said Constantine A. Gatsonis, PhD, a lead statistician for the study and a professor of biostatistics at Brown University.
He encourages physicians to consider the new data when they are deciding what test to recommend for screening a patient's lungs.
Lung cancer is the leading cause of cancer-related death among men and women in the U.S., according to the Centers for Disease Control and Prevention. The NCI estimates that 222,520 new cases of lung cancer will be diagnosed this year, and 157,300 people will die of the disease.
Researchers examined data on 53,456 current and former heavy smokers age 55 to 74 who were enrolled in the National Lung Screening Trial between August 2002 and April 2004. Participants smoked at least one pack a day for 30 years and had no signs, symptoms or history of lung cancer.
About half of the individuals were randomly assigned to receive three annual low-dose CT scans, and the other half got three standard x-rays. Participants were screened when they enrolled in the study and at the end of their first and second years in the trial. Then they were followed for as many as seven years. Radiologists reviewed the images for lung nodules and masses. Participants whose tests revealed an abnormality received follow-up recommendations.
At the end of the study in October, 796 of the participants had died of lung cancer. In the group that received CT scans, 44.5% died of the disease. The figure was 55.5% among those who got x-rays (link).
The potential disadvantages of CT procedures include the cumulative effects of radiation from multiple scans and false positives that can lead to unnecessary lung biopsies.
"At the end of the day, we have to balance the risks of [lung cancer] screening with the benefits. That will be part of a more detailed analysis" of the study's findings, which will be published in the near future, Gatsonis said.