Starting in 2002, more than 50,000 current and former smokers aged 55 to 74 signed up for the National Lung Screening Trial (NLST) at Johns Hopkins and more than 30 other sites across the nation. The trial was to last 10 years, but eight years into the study, leaders of the trial found their results thus far were significant enough to stop the trial and announce their findings.
The initial findings, announced today, show that trial participants receiving annual low-dose helical computed tomography (CT) scans had 20 percent fewer lung cancer deaths than those who received standard chest x-rays. Study participants included men and women with at least 30 years of heavy smoking history.
During a news conference, leaders at the National Cancer Institute said it's still unclear whether anticipated guidelines for screening may recommend annual scans. They will continue analyzing data and said that some questions may be answered when more data is reviewed and released in about three months.
Johns Hopkins CT expert Elliot Fishman, M.D., and principal investigator of the Hopkins site, said that the current results only answer the question of whether CT scans improve survival. A major question that remains, he says: "What should an individual patient do?"
CT scans can detect small nodules that need further evaluation, whether by biopsy or other imaging devices, and the additional tests can cause anxiety, more costs, and medical procedures that carry further risk to patients.
Yet, "initial evidence seems to lean toward a benefit for CT scans in heavy smokers at the highest risk of getting lung cancer," says Fishman.
Fishman's advice to smokers is to talk with their primary health care provider about their risk for lung cancer. Still, quitting smoking is "the single best way to prevent lung cancer deaths," said NLST national principal investigator Denise Aberle, M.D., in a statement, and smokers shouldn't be misled that CT scans are a fail-safe for lung cancer.
Health care professionals with questions should contact Elliot Fishman, M.D., directly.
More information about NLST from the National Cancer Institute
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The fact that the risk from the low dose CT of the chest, is by far less risky than missing a lung cancer at its early stages and the risk it puts on the patient and his family from the health, social and economic perspectives.
Till we find a non radiation tool for screening for lung cancer, this hopefully remains the only hope.
Dear Dr.Fishman,
ain't it simply lead time bias????so far no radiological intervention has indicated for screening for lung cancers,so why you think this particular study is not biased!
Good question -- The National Cancer Institute addressed questions related to several points of potential bias. To ensure that a screening method isn't simply adding time on to the front-end of diagnosis (lead-time bias), studies need to show that the screening method changes the end result, which is mortality. That's why they used mortality as an endpoint and not case survival. The NCI does a nice job of explaining this in their Q&A on this page: http://www.cancer.gov/newscenter/qa/2002/nlstqaQA (see Question 20, and for other readers who want to read definitions on lead-time, length and overdiagnosis bias, there are good definitions and diagrams on the same Web page below Question 20).
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