The weather outside may be cooling off but the debate surrounding lung cancer screening is heating up once again as preliminary results released from The National Lung Screening Trial (NLST) showed 20% fewer lung cancer deaths in individuals that underwent screening with low-dose helical CT scans compared to chest X-ray. This is the first study to show a mortality benefit from lung cancer screening and could impact millions of people considered high-risk for lung cancer. The study’s initial findings were released by the National Cancer Institute this week when an independent Data and Safety Monitoring Board found a convincing difference in lung cancer mortality between the two groups .
A multi-centered randomized trial, NLST enrolled 53,456 former and current smokers age 55-74 years with at least a 30 pack-year smoking history between August 2002 and April 2004 . Participants were assigned to annual screening over a three year period with low-dose helical CT or chest X-ray and followed for an additional five years. The primary endpoint was lung cancer mortality while secondary endpoints included all-cause mortality and lung cancer incidence, case survival and stage distribution. The most recent results showed 354 lung cancer deaths in the CT group and 442 lung cancer deaths in the chest X-ray group (a relative risk reduction of 20.3%). The results also showed a 7% lower all-cause mortality in the CT arm.
Several randomized trials over the last 40 years have failed to show a mortality benefit from lung cancer screening. More recently the DANTE trial, a prospective randomized trial of 2,800 men aged 60-75 years with at least a 20 pack year history, used low-dose CT to screen for lung cancer . While screening with low-dose CT detected lung cancer at a higher rate, it failed to show a mortality benefit.
While full analysis of the study results will be needed before any conclusions regarding lung cancer screening can be made, clinicians can look forward to heated debate surrounding this controversial topic in the months to come.
The complete study design of the NLST is available in the journal Radiology.
Dr. Hormozdi is a second year resident at NYU Langone Medical Center
Image courtesy of Wikimedia Commons.
2. NLST Research Team. The National Lung Screening Trial: Overview and Study Design. Radiology. 2010 Nov 2. Epub ahead of print. http://radiology.rsna.org/content/early/2010/10/28/radiol.10091808.full#ref-list-1
3. Infante, M., S. Cavuto, F.R. Lutman, et al. 2009. A randomized study of lung cancer screening with spiral computed tomography. American Journal of Respiratory Critical Care Medicene 180: 445–453. http://ajrccm.atsjournals.org/cgi/content/short/180/5/445