Low-Dose CT Scan Screening May Save Lives

Results from the National Cancer Institute's National Lung Screening Trial (NLST), which was recently published in the New England Journal of Medicine revealed that screening high-risk individuals with low-dose CT scans reduced lung cancer deaths by 20 percent compared with chest x-ray.

The trial, which was ended early due to these promising results, enrolled participants who were current and former smokers with no history of cancer, who smoked the equivalent of one pack a day for 30 years, and were between the ages of 55–74 years old. Roughly 7 million out of 94 million current and former smokers in the United States fit this demographic.

Participants were randomly assigned to receive three annual screening exams with either a CT scan or a chest x-ray. The researchers found 247 deaths from lung cancer per 100,000 person-years in the low-dose CT group and 309 deaths per 100,000 person-years in the radiography group, representing a relative reduction in mortality from lung cancer with low-dose CT screening of 20.0 percent.

The majority of lung cancers detected by the CT scan and chest x-ray were in earlier, more treatable stages, however, this distribution was more favorable in the CT scan group. Non-small cell lung cancers, such as adenocarcinomas and squamous cell lung cancers, were the predominate type found by both CT scans and chest x-rays. Unfortunately, the more aggressive type of lung cancer, small cell, was not detected in early stages by either group.

The authors of this study carefully pointed out that the study did not provide enough evidence to move forward with lung cancer screening recommendations. However, this study and other relevant ones will be reviewed by the U.S. Preventive Services Task Force in 2012 to develop recommendations for medical providers and health systems.

While the NLST results are an important step forward in the fight against lung cancer, smoking cessation continues to be the single most important thing any smoker can do to reduce their hances of developing or dying from lung cancer. Of course, prevention of the start of tobacco use, which occurs mostly in adolescence, is even more effective.

Sources

The National Lung Screening Trial Research Team. Reduced Lung-Cancer Mortality with Low-Dose Computed Tomographic Screening. N Engl J Med, 365; 5,395-409.