Extended Follow-up From the National Lung Screening Trial Reported
Early detection and treatment through screening with low-dose computed tomography (LDCT) has been investigated as a potential means of reducing lung cancer mortality for more than 2 decades. In 2011, a large U.S. study—the randomized National Lung Screening Trial (NLST)—reported a 20% reduction in lung cancer mortality in high-risk current and former smokers screened annually for 3 years with LDCT as compared to chest x-rays. The NLST study included 26,722 patients in the LDCT arm and 26,730 in the x-ray arm at 33 sites in the United States.
Now, in a new report by Black et al in the Journal of Thoracic Oncology, the authors of the NLST research report on an extended analysis of the patient cohort that was followed up on after the initial 2011 study was published. The authors report that their original findings have been sustained. This follow-up study also supports and reaffirms findings from the NELSON trial, which found a 26% reduction in lung cancer mortality in men and a 39% reduction in women with the use of LDCT.
The NLST study randomly assigned high-risk current and former smokers to three annual screens with either LDCT or chest radiographs, and demonstrated a significant reduction in lung cancer mortality in the LDCT arm after a median of 6.5 years follow-up. In this latest report, lead researcher Paul Pinsky, PhD, of the National Cancer Institute, and colleagues extended the follow up to 12.3 years for mortality.
Follow-up Findings
The study authors wrote that with an additional 6 years of mortality follow-up, researchers could better understand if LDCT prevented deaths from lung cancer or merely delayed them. They report that the extended follow-up allowed them to determine that LDCT did, in fact, prevent lung cancer deaths—or at least delayed them for more than a decade.
“Lung cancer is the leading cause of cancer death worldwide, and early detection and treatment through screening with LDCT has been investigated as a potential means of reducing lung cancer deaths for more than 2 decades. This study adds further weight to the notion that CT screening is effective,” said Dr. Pinsky in a press release.
The original report in 2011 found that 320 patients would have to be screened to prevent one death from lung cancer, while the current follow-up research found that 303 patients would have to be screened to prevent one lung cancer death.
The dilution-adjusted lung cancer mortality rate ratios was 0.89 (95% confidence interval [CI] = 0.80–0.997). For overall mortality, there were 5,253 deaths in the LDCT arm and 5,366 deaths in the chest x-ray arm, for a difference across arms (per 1,000) of 4.2 (95% CI = -2.6–10.9).
The study authors concluded that extended follow-up of the NLST showed a similar number needed to screen to prevent 1 lung cancer death as the original analysis. Further, the extended analysis reaffirms previously published research that shows screening patients at high risk for lung cancer can reduce lung cancer mortality.
Disclosure: For full disclosures of the study authors, visit jto.org.
The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.
