CT Scan to Screen for Lung Cancer: Part 1

The majority of people who develop lung cancer are not diagnosed until it is too late. One of the chief reasons for late diagnosis is because there are no suitable screening tests. Unlike breast or colon cancer, there are no radiological tests for screening lung cancer.  Plain chest x-rays are simply not sensitive enough to identify lung cancer in the early stages. For many years, it was believed that CT scans were not suitable for lung cancer screening. However, now a recent study funded by the National Cancer Institute showed that when CT scans were used to screen patients for lung cancer, at least 20 % fewer patients died from this horrible cancer.

This is the first time it has been shown that perhaps CT scans can be used as a screening test. The present study known as the  National Lung Screening Trial, involved more than 53,000 current and former heavy smokers ages 55 to 74, and was designed to compare two screening procedures for lung cancer—low-dose helical computed tomography and a chest X-ray.

The study clearly showed that lung cancer screening by CT scan reduced lung cancer deaths because it identified lung cancers at an early stage. The data were so statistically compelling the trial was discontinued and the results immediately made public. The results of the study revealed that CT screening could benefit older, high-risk patients.

Principal investigator Dr. Denise Aberle, for the American College of Radiology Imaging Network (ACRIN) said, "We have the potential to save thousands of lives if low-dose screening is implemented responsibly, and people with abnormalities are closely followed.”

The majority of participants in the study smoked at least a pack a day for 30 years and had no symptoms of lung cancer. They were screened once a year for three years and followed for an additional five years.

"This is the first time that we have seen clear evidence of a significant reduction in lung cancer mortality with a screening test in a randomized controlled trial," said Dr. Christine Berg, NLST project officer for the Lung Screening Study. "The fact that low-dose helical CT provides a decided benefit is a result that will have implications for the screening and management of lung cancer for many years to come."