Mortality from lung cancer is the highest among all cancers. Chest x-rays have been used successfully to detect lung cancers. However, a recent trial, known as the National Lung Screening Trial, has found that compared to chest x-rays, CT scans of the chest are more sensitive in diagnosing lung cancers and can be deployed more frequently to bring down mortality from lung cancer. The research, which has been published in the recent issue of the New England Journal of Medicine, was carried out by Timothy R. Church and his colleagues from the University of Minnesota, School of Public Health in Minneapolis.
For their study, the researchers enrolled 53,439 asymptomatic participants between August 2002 and April 2004. All of the participants were between 55 to 74 years of age and had a history of 30 pack years (number of packs of cigarettes smoked per days times the number of years the person has smoked) of smoking. The participants were randomly divided into two groups and were subjected to either a chest x-ray or chest CT scan, annually for three years. Any nodule or suspicious findings were considered as positive.
It was seen that 27.3% of the participants who were subjected to a low dose CT scan showed a positive screening result compared to just 9.2% of the participants who were subjected to a chest x-ray.
Mortality from lung cancer was 20% less with chest CT scan
The researchers observed that the participants subjected to CT scans showed substantially more positive results, which led to a decrease in the mortality from lung cancer by almost 20%. The sensitivity and specificity of lung cancer detection with the CT scan were 94% and 73% respectively. By contrast, the sensitivity and specificity of a chest x-ray in the detection of lung cancer was 74% and 91%. The number of lung cancers diagnosed at stage I were 158 with the CT scan compared to 70 with the chest x-ray.
The sensitivity of the chest CT scan in diagnosing lung cancer is 20% higher than that of a chest x-ray. This can help in bringing down the mortality from lung cancer.
- The National Lung Screening Trial Research Team. Results of Initial Low-Dose Computed Tomographic Screening for Lung Cancer N Engl J Med 2013; 368:1980-1991; DOI: 10.1056/NEJMoa1209120