WASHINGTON, DC – A large national study finds that screening current or former heavy smokers with a CT scan can reduce deaths from lung cancers by 20 percent, according to a study published today in the New England Journal of Medicine. Researchers point out that the screening does carry risk, though not common. The screening study was conducted by the National Cancer Institute at 33 centers around the country including Georgetown Lombardi Comprehensive Cancer Center, a part of Georgetown University Medical Center and Georgetown University Hospital (GUH).
The National Lung Screening Trial, called NLST, involved more than 53,000 current and former heavy smokers ages 55 to 74. Under Lombardi’s leadership, 1,800 men and women were recruited into the clinical trial at Lombardi as well as two other Georgetown University Hospital community-screening locations.
The study compared the effects of two screening procedures for lung cancer -- low-dose helical computed tomography (CT) and standard chest X-ray. It also examined complications from follow up procedures after a positive result.
“These results are significant. It is clear from this study that CT screening of smokers or former smokers at high risk of developing lung cancer can save lives,” says Claudine Isaacs, MD, lead investigator of the NLST study at Georgetown Lombardi. “That said, with the newly published results, we’re getting a look at the false-positive rate and the complications that can come with follow-up procedures to positives scans. This is important information when weighing the risks and benefits of screening.”
False-positive results describe scans that show a lesion or artifact in the lung but after a follow up CT scan or invasive procedure (such as a biopsy) are determined to not be lung cancer.
In this study, 96 percent of positive CT scans turned out to be false-positives. A scan was classified as a false-positive result if a repeat scan or invasive procedure such as a biopsy determined the artifact seen in the first scan was not likely to be cancer. Researchers described complications with invasive procedures as “uncommon,” but some deaths were reported.
“We are grateful to all the men and women who participated in this important study. Clinical trials are critical to making progress in medicine,” Isaacs says.
“Going forward, we need to determine who best benefits from this screening and ensure that we are offering those at risk the best course of screening,” says Louis Weiner, MD, director of Georgetown Lombardi. “While studies like these generate excitement, clearly there is much more work to be done. Lombardi and our MedStar partner hospitals continue to explore effective ways to reduce lung cancer deaths including prevention and screening efforts, and by conducting clinical trials with the newest diagnostic tools and available cancer fighting drugs.”
More about NLST
The NLST study began enrolling participants in August 2002. Participants were required to have a smoking history of at least 30 pack-years and were either current or former smokers without signs, symptoms, or history of lung cancer. Pack-years are calculated by multiplying the average number of packs of cigarettes smoked per day by the number of years a person has smoked.
The men and women 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 the time of 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. A total of 356 deaths from lung cancer had occurred among participants in the CT arm of the study, whereas a significantly larger 443 lung cancer deaths had occurred among those in the chest X-ray group. This represents a 20 percent reduction in lung cancer mortality offered by CT scans compared to the X-ray group.
More information about the NLST research team at Georgetown's can be found on the GUMC website. Additional information about the study can be found at NCI’s website.
The NLST was sponsored by NCI, a part of the National Institutes of Health, and conducted by the American College of Radiology Imaging Network (ACRIN) and the Lung Screening Study group. For more information about the study, please call the NCI's Cancer Information Service at 1-800-4-CANCER (1-800-422-6237).
About Georgetown Lombardi Comprehensive Cancer Center
Georgetown Lombardi Comprehensive Cancer Center, part of Georgetown University Medical Center and Georgetown University Hospital, seeks to improve the diagnosis, treatment, and prevention of cancer through innovative basic and clinical research, patient care, community education and outreach, and the training of cancer specialists of the future. Georgetown Lombardi is one of only 40 comprehensive cancer centers in the nation, as designated by the National Cancer Institute, and the only one in the Washington, DC, area. For more information, go to http://lombardi.georgetown.edu.
About Georgetown University Medical Center
Georgetown University Medical Center is an internationally recognized academic medical center with a three-part mission of research, teaching and patient care (through MedStar Health). GUMC’s mission is carried out with a strong emphasis on public service and a dedication to the Catholic, Jesuit principle of cura personalis -- or "care of the whole person." The Medical Center includes the School of Medicine and the School of Nursing & Health Studies, both nationally ranked; Georgetown Lombardi Comprehensive Cancer Center, designated as a comprehensive cancer center by the National Cancer Institute; and the Biomedical Graduate Research Organization (BGRO), which accounts for the majority of externally funded research at GUMC including a Clinical Translation and Science Award from the National Institutes of Health. In fiscal year 2009-2010, GUMC accounted for nearly 80 percent of Georgetown University's extramural research funding.