Ambassador Blog Series: Javad Azadi of Johns Hopkins provides an overview of the National Lung Screening Trial

December 31, 2014

Javad_Azadi Hopkins

Name: Javad Azadi, MSIV
Institution: Johns Hopkins University School of Medicine
Undergrad: Ohio State University 

Trial: National Lung Screen Trial Review 

Reference: The National Lung Screening Trial: overview and study design in Radiology
Date: January 1, 2011

Reference: Reduced Lung-Cancer Mortality with Low-Dose Computed Tomographic Screening in the New England Journal of Medicine
Date: June 29, 2011

Cancer is fast approaching heart disease as the number one cause of death in the United States.  Of all causes of cancer, lung cancer is notorious not only because it is the second most common cancers in both genders, but also because it is also leads to the most deaths annually.1 Prior to 2011, numerous trials had looked into early screening of lung cancer.  Past work includes studying sputum cytology and serial chest radiographs in high-risk populations, but neither method reduced mortality.  The National Lung Screen Trial (NLST) research team was the first to show screening with low-dose CT reduced lung cancer mortality.2

The National Lung Screening Trial ( number, NCT00047385) ran from August 2002 through April 2004.  The trial enrolled 53,454 patients who were determined to be at high-risk for lung cancer across 33 U.S. medical institutions.  Eligible patients were 55-74 years old, had a 30 or more pack year smoking history, and had not quit smoking greater than 15 years prior to the start of the study.  Patients were not eligible for the study if they had a previous history cancer other than non-melanoma skin cancer in the past 5 years, a history of lung cancer, any removal of lung tissue including biopsy, home oxygen requirements, unexplained weight loss during 12 months prior to the study, pneumonia or acute respiratory infection treated within 12 weeks prior to the study, or a recent chest CT during the 18 months prior to the study.  Of the 53,454 patients enrolled, they were randomly assigned to receive a low-dose CT screen or a single view posteroanterior chest radiography screen.  A baseline screen was followed by two more screenings occurring annually.  The NLST research team was able to demonstrate that low-dose CT reduced lung cancer mortality compared to chest radiography.  Specifically, they found 247 deaths from lung cancer per 100,000 person-years in the low-dose CT group compared to the 309 deaths per 100,000 person-years in the radiography group.  This represented a 20.0% (95% CI, 6.8 to 26.7; P=0.004) decrease in lung cancer mortality, and similarly all-cause mortality decreased by 6.7%.3

While the NLST trial is the first major randomized control trial to demonstrate screening with low-dose CT can reduce the mortality of lung cancer, it is worth noting that this study validates the continued need for improved smoking cessation strategies as another means to reduce lung cancer mortality. 


1.     Murphy SL, Xu J, Kochanek KD. Deaths: Preliminary Data for 2010. Natl Vital Stat Rep 2012;60(4):1–52.

2.     National Lung Screening Trial Research Team, Aberle DR, Berg CD, et al. The National Lung Screening Trial: overview and study design. Radiology 2011;258(1):243–53.

3.     National Lung Screening Trial Research Team, Aberle DR, Adams AM, et al. Reduced lung-cancer mortality with low-dose computed tomographic screening. N Engl J Med 2011;365(5):395–409.


The opinions expressed are the sole opinions of the author. If content is related to general and specific health issues, the information contained in the Site is made available with the express understanding that neither Docphin and/or the other authors on the Site, nor the Site itself, nor members of the Site are dispensing medical advice and do not intend any of this information to be used for self diagnosis or treatment. IF YOU HAVE ANY QUESTIONS OR CONCERNS ABOUT YOUR HEALTH AND BEFORE STARTING OR STOPPING ANY TREATMENT OR ACTING UPON INFORMATION CONTAINED ON THE SITE, YOU SHOULD CONTACT YOUR OWN PHYSICIAN OR HEALTH CARE PROVIDER