Spiral CT screening of heavy smokers could decrease lung cancer death rates
Heavy smokers who have lung cancer screening with low-dose 'spiral' chest CT scans appear to be less likely to die from the disease than those who are screened using single view chest x-rays, initial study results from the US National Cancer Institute (NCI) suggest.
Spiral CT uses x-rays to obtain a multiple-image scan of the entire chest, whereas standard chest x-rays produce a single image.
The institute has published early results from a large-scale trial of screening methods in older people with a high risk of smoking-related lung cancer, but a full analysis is yet to be performed.
Researchers collected data on more than 53,000 current and former heavy smokers, aged 55 to 74, in order to compare the effect of low-dose spiral chest CT and standard chest x-rays on the risk of dying from lung cancer.
Participants underwent screening each year for three years and were then followed for up to five years to see whether they died from lung cancer.
The National Lung Screening Trial (NLST) found there were 20.3 per cent fewer lung cancer deaths among high-risk patients screened with low-dose spiral CT than with chest x-rays.
The overall death rate from all causes was also seven per cent lower in people who had CT scans, although the researchers said they were unsure why this might be the case, and that a full analysis would follow.
NCI director Dr Harold Varmus said: "This large and well-designed study used rigorous scientific methods to test ways to prevent death from lung cancer by screening patients at especially high risk.
"Lung cancer is the leading cause of cancer mortality in the US and throughout the world, so a validated approach that can reduce lung cancer mortality by even 20 per cent has the potential to spare very significant numbers of people from the ravages of this disease.
"But these findings should in no way distract us from continued efforts to curtail the use of tobacco, which will remain the major causative factor for lung cancer and several other diseases."
Dr Denise Aberle, NLST national principal investigator for the American College of Radiology Imaging Network, which conducted the research, said: "The results of this trial provide objective evidence of the benefits of low-dose helical CT screening in an older, high-risk population and suggest that if low-dose helical CT screening is implemented responsibly, and individuals with abnormalities are judiciously followed, we have the potential to save thousands of lives."
However, Dr Aberle noted: "Given the high association between lung cancer and cigarette smoking, the trial investigators re-emphasise that the single best way to prevent lung cancer deaths is to never start smoking, and if already smoking, to quit permanently."
Professor Stephen Duffy, Cancer Research UK's screening expert, said he thought the results were 'very encouraging' but that a full analysis was needed to confirm the risks as well as the benefits.
"For many years, we've been looking for a method to substantially reduce deaths from lung cancer. We look forward to seeing the full details published, telling us the disadvantages as well as the benefits of the screening," he said.
"The work to reduce smoking exposure is still vitally important though - as nine out of ten lung cancers are caused by smoking. In the meantime, however, these initial results may be the most positive in lung cancer control for a long time."