Saving the Lives of Heavy Smokers

Low-dose helical CT scans reduce lung cancer deaths in smokers

(RxWiki News) Lung cancer is most commonly detected with a chest X-ray. This standard technique misses a number of early cancers, though. A study shows another technology is not only a better screening tool, but can save the lives of smokers.

People who are currently or used to be heavy smokers have a more reliable way of detecting lung cancer in its earlier more treatable stages. A nearly 10-year study has found that compared to conventional chest X-rays, low- dose helical computed tomography (CT) can reduce lung cancer deaths by 20 percent.

"Smokers and former smokers should ask for CT scans instead of chest X-rays."

The National Lung Screening Trial (NLST) was a randomized national trial that worked with 53,454 current and former heavy smokers between the ages of 55 and 74. Participants had a history of at least 30 pack-years (average number of packs smoked by number of years person smoked) with no signs, symptoms, or history of lung cancer.

Participants received three annual screens using either low-dose helical CT (known as spiral CT) or standard chest X-ray. The spiral CT produces a number of images of the entire chest, while a standard X-ray creates only a single image.

The spiral CT scans picked up 24.6 percent adnormalities that could potentially be lung cancer. Chest X-rays identified 6.9 percent potential problem areas.

The spiral CT scans were far more effective in identifying two types of lung cancer earlier than the standard chest X-ray:

  • Adenocarcinomas that starts in the cells that line the lungs
  • Squamous cell carcinomas which start in the cells that line respiratory tract passages

A very aggressive form of the disease - small-cell lung cancers - were not detected in early stages by either method.

Both methods produced a high number of false positives (CT - 96.4 percent; X-rays - 94.5 percent) where the abnormalities were not linked to cancer. Follow-up studies to rule out cancer can be both invasive and expensive.

As a result, more study is needed before recommendations can be made.

Despite the challenges that still remain, knowing that there's screening method that can actually reduce mortality in heavy smokers is tremendously important, says Constantine Gatsonis, one of the study's lead statisticians and chair of biostatistics in the public health program of the Warren Alpert Medical School of Brown University.

The NLST was sponsored by the National Cancer Institute (NCI), part of the National Institutes of Health, and involved researchers from Brown University, Dartmouth College and the NCI.

The primary research results from the National Lung Screening Trial (NLST) are published in The New England Journal of Medicine.

Review Date: 
July 5, 2011