June 29, 2011
Results from the National Lung Screening Trial (NLST) released today show 20% fewer lung cancer deaths for people screened with low-dose helical computed tomography (CT) than a with chest x-ray.
The NLST involves more than 53,000 people ages 55 to 74 who are current and former “heavy” smokers, defined as smoking the equivalent of a pack of cigarettes each day for 30 years. None of the participants had any signs or symptoms of lung cancer. The NLST was sponsored by the National Cancer Institute (NCI) and conducted by the Lung Screening Study group and the American College of Radiology Imaging Network at 33 trial sites across the United States.
In this study, the participants were screened with either a standard x-ray or a low-dose helical CT scan when they entered the study, and then at the end of their first and second years on the study. A low-dose helical CT test (sometimes called a spiral CT) creates a three-dimensional picture of the inside of the body with an x-ray machine. A computer then combines these images into a detailed, cross-sectional view that shows any abnormalities or tumors. The study participants were then followed for up to five years, and the researchers recorded the deaths specifically due to lung cancer.
Since the 2002 launch of the NLST, a total of 356 deaths from lung cancer had occurred among the participants who received screening with CT versus 443 participants who received screening with a chest x-ray.
What This Means for Patients
“This is a very exciting and important result, with a reduction in deaths that could be as high as 20%,” said Bruce E. Johnson, MD, ASCO Board Member, Director, Lowe Center for Thoracic Oncology, Dana-Farber Cancer Institute. “Lung cancer is by far the leading cancer killer in the United States, with more than 157,000 deaths annually. One of our greatest challenges has been catching it early enough to treat it effectively. This study fills a huge gap in lung cancer control, and ASCO is currently examining the most appropriate method for implementing its findings.”
Dr. Johnson also cautioned against using screening as a substitute for quitting smoking. “The overwhelming majority of lung cancer is caused by smoking, and smoking cessation will always have a far greater impact on lung cancer deaths than any screening tool. For Americans who wish to prevent deaths from cancer, respiratory illness or heart disease, the first step is to quit smoking.”
ASCO is developing a clinical practice guideline on lung cancer screening with the National Comprehensive Cancer Network, American Cancer Society and the American College of Chest Physicians to help doctors and patients better asses the risks and benefits of CT scans for lowering deaths from lung cancer. Additionally, the guideline will be updated as the results of other ongoing randomized lung cancer screening trials around the world are reported.
What to Ask Your Doctor
- What is my risk of lung cancer?
- How can you help me quit smoking?
- What the risks and benefits of screening?
- How will I learn the results of the test?
- What are the next steps if the CT scan indicates cancer?
- Where can I get more information?