It seems screening for lung cancer doesn't save lives and it doesn't prevent advanced disease. But it does lead to potentially unnecessary and harmful treatment.

This isn't the final word on the use of CT scans to screen smokers and former smokers for the disease. But right now, the hope some experts had for the special X-rays to detect tiny lung abnormalities has been diminished by a large study that is still in the works. And until conclusive evidence says the screening is useful, the American Cancer Society will not endorse the test.

While CT screening did increase diagnosis and treatment -- those screened were three times more likely to be diagnosed with lung cancer and 10 times more likely to have lung surgery than predicted -- study co-author Dr. Peter Bach of Memorial Sloan-Kettering Cancer Center in New York says, "We don't see a trace of evidence that a single life was saved, that a single case of advanced cancer was avoided."

And because CT scanning led to more biopsies and surgeries, patients were put at risk for complications such as lung puncture, bleeding, and infection, according to Bach, whose work is published in the Journal of the American Medical Association.

"Getting screened for lung cancer with CT scanning is not only unproven, it's potentially a risky endeavor," he said.

Until an effective screening tool emerges -- possibly still years away -- experts say there is one surefire way to protect yourself from lung cancer. Stop smoking.