"Late-staged treatment is more costly than early-stage treatment," said Henschke, whose initial 1999 study published in Lancet showed that CT scans were more effective than chest x-rays to pick up earlier-stage lung cancers. Henschke was not involved in the latest NCI trial.
While the latest trial showed that CT scans screening decreased the number of people who died from lung cancer, Varmus said CT scans should not be used to prevent the disease among the general population.
The results of the study only applied to heavy current and previous smokers deemed at higher risk for lung cancer. The best way to prevent the disease, he said, is to stop smoking.
According to Dr. Joseph Bokar, medical oncologist at University Hospitals Case Medical Center in Cleveland, Ohio, quitting smoking is "more effective than any screening program."
In fact, not all folks who are at high risk for lung cancer should ask for CT scans, according to Dr. Len Lichtenfeld, deputy chief medical officer at the American Cancer Society. Screening may not be appropriate for those who suffer from later-stage lung or heart disease, he said.
"Ask yourself the question, if you find an abnormality, are you in good enough condition to go through the surgery or the treatment that follows," said Lichtenfeld.
And questions still remain on how best to implement CT scans as a screening tool for lung cancer. Although many studies suggest x-ray does not prevent lung cancer death, Lichtenfeld said only individual doctors can evaluate the best screening method for each patient.
"What was not said today is that we have enough to make a blanket recommendation that everyone get screened [by CT scans]," said Lichtenfeld. "It's going to take time for experts to give it some thought."
"For all this we really need to develop guidelines," said Henchke.
Investigators said they plan to publish full review of their results in subsequent months.
"All of these considerations have implications for recommendations," said Lowy. "Further analysis will be needed before concluding broader use for this method."