20% fewer lung cancer deaths seen among those who were screened with low-dose spiral CT than with chest X-ray
Below are excerpts from the NCI press briefing. It is important to note that, even though the results of the NLST trial are impressive and offer hope to the millions of Americans at high risk of developing lung cancer, there is considerable debate among the oncology community about the true life-saving value of CT screening.
This trial, most likely, will not end the debate, but will instead provoke a new round of discussion. Practice & Policy will continue to follow this important issue. Please add your voice to the debate. If you would like to contribute an article, letter, or short blog post at this site, please contact Ronald Piana at Ronald.firstname.lastname@example.org
NCI released initial results from the National Lung Screening Trial (NLST), a randomized national trial involving more than 53,000 current and former heavy smokers ages 55 to 74, compared the effects of two screening procedures for lung cancer -- low-dose helical computed tomography (CT) and standard chest X-ray -- on lung cancer mortality and found 20 % fewer lung cancer deaths among trial participants screened with low-dose helical CT.
Starting in August 2002, the NLST enrolled about 53,500 men and women at 33 trial sites nationwide over a 20 month period.
Participants were randomly assigned to receive three annual screens with either low-dose helical CT (often referred to as spiral CT) or standard chest X-ray. Helical CT uses X-rays to obtain a multiple-image scan of the entire chest during a 7 to 15 second breath-hold. A standard chest X-ray requires only a sub-second breath-hold but produces a single image of the whole chest in which anatomic structures overlie one another. Previous efforts to demonstrate that standard chest X-ray examinations can reduce lung cancer mortality have been unsuccessful.
The trial participants received their screening tests at enrollment and at the end of their first and second years on the trial. The participants were then followed for up to another five years; all deaths were documented, with special attention given to the verification of lung cancer as a cause of death.
At the time the DSMB held its final meeting on October 20, 2010, a total of 354 deaths from lung cancer had occurred among participants in the CT arm of the study, whereas a significantly larger 442 lung cancer deaths had occurred among those in the chest X-ray group. The DSMB concluded that this 20.3% reduction in lung cancer mortality met the standard for statistical significance and recommended ending the study.
NCI Director, Harold Varmus said in a statement: “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 U.S. and throughout the world, so a validated approach that can reduce lung cancer mortality by even 20% has the potential to spare very significant numbers of people from the ravages of this disease.”
A paper describing the design and protocol of the NLST, “The National Lung Screening Trial: Overview and Study Design” by the NLST research team, was published yesterday by the journal Radiology and is openly available at http://radiology.rsna.org/cgi/content/abstract/radiol.10091808.
Participants in the NLST are being notified individually of the findings by the study’s investigators. The participant notification letter, as well as the DSMB letter, can be viewed at http://www.cancer.gov/clinicaltrials/noteworthy-trials/nlst.
Copies of the DSMB and NLST participant letters can be found on the NLST site at http://www.cancer.gov/clinicaltrials/noteworthy-trials/nlst.
For a Q&A on the NLST, please go to http://www.cancer.gov/newscenter/qa/2002/nlstqaQA.
For a Fact Sheet on the NLST, please go to http://www.cancer.gov/newscenter/pressreleases/NLSTFastFacts.
For more information on lung cancer and screening, please go to http://www.cancer.gov/cancertopics/types/lung.
“The National Lung Screening Trial: Overview and Study Design" has been published by Radiology. This paper is openly available at http://radiology.rsna.org/cgi/content/abstract/radiol.10091808.