Using CT scans to screen patients who have a high risk of developing lung cancer could help in detecting the disease at a more curable stage and reduce lung cancer deaths, scientists said today.

Preliminary results from the Early Lung Cancer Action Project (ELCAP) published in The Lancet medical journal showed that a technique called low-dose computed tomography (CT) detected more tumors and early signs of lung cancer than chest X-rays.

"Our results confirm the expectation that, compared with chest radiography, low-dose CT greatly increases the likelihood of detection . . . of lung cancer at an earlier, curable stage," said researcher Claudia Henschke.

Screening for lung cancer was generally considered ineffective after four trials set up in the 1970s failed to show that it reduced deaths from the disease.

Henschke and her colleagues at New York Presbyterian Hospital-Weill Cornell Medical Center and McGill University in Montreal tested 1,000 high-risk people -- heavy smokers over the age of 60.

CT, which gives more precise images than normal chest X-rays, detected six times as many early-stage tumors as X-rays, four times more cancerous nodules, or groups of cells, and three times more swellings that raise the suspicion of cancer.

Lung cancer is the most common form of cancer and affects more than one in every 1,000 people. Smoking is a leading cause of the illness. If detected in the earliest stages, up to 70 percent of cases can be cured by surgery.