Cancer Research Lab

Although screening with low-dose CT may increase detection of lung cancer, it does not lead to a meaningful reduction in deaths from the malignancy, new research suggests. As such, further studies are needed to determine whether CT screening for lung cancer should become standard practice.

CT screening of current and former smokers is used at a number of centers based on the belief that such screening will catch lung cancer at an early, more curable stage. However, there are limited data to support that screening actually improves outcomes.

In the present study, reported in the Journal of the American Medical Association for March 7, Dr. Peter B. Bach, from the Memorial Sloan-Kettering Cancer Center in New York, and colleagues assessed the outcomes of 3246 asymptomatic current or ex-smokers who were screened for lung cancer starting in 1998. The median follow-up period was 3.9 years.

Low-dose CT screening was performed on an annual basis with standard treatment applied to any detected lesions.

As noted, CT screening did increase detection of lung cancer. A total of 144 people were diagnosed with lung cancer when only 44.5 cases were expected. Similarly, 109 patients underwent lung resections, while just 10.9 cases were expected.

CT screening also did not result in detection in fewer cases of advanced lung cancer. In fact, the number diagnosed exceeded the number expected: 42 vs. 33.4. Similarly, deaths from lung cancer did not fall either: 38 occurred vs. 38.8 expected.

As Dr. Brach’s group mentions, “formulation of (a CT-based) screening policy should await the rigorous assessment that will be provided by ongoing randomized controlled trials (the National Lung Screening Trial and the NELSON Trial),” Drs. William C. Black and John A. Baron, from Dartmouth Medical School in Hanover, New Hampshire, note in a related editorial.

“Although expensive and time-consuming, rigorous trials of cancer screening are far more cost-effective than what might be the alternative - widespread adoption of costly screening interventions that cause more harm than good,” they add.