Study Shows CT Scans Cut Lung Cancer Deaths Long-awaited results from a big federal study show that screening smokers and former smokers with CT scans cuts the risk of dying from lung cancer by 20 percent. But many questions remain about how these findings should be applied to more than 90 million Americans who smoke or once did.

Study Shows CT Scans Cut Lung Cancer Deaths

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A new federal study shows there's a test that could reduce lung cancer deaths by 20 percent. That could potentially save tens of thousands of lives per year. The test is called CT screening. It uses computerized x-ray machines to detect many lung cancers when they're too small to cause symptoms. The new study follows a long debate about whether CT lung screening really does save lives. NPR's Richard Knox has this report.

RICHARD KNOX: U.S. smoking rates are way down from what they used to be. And lung cancer rates are beginning to come down too. But in case you think the problem is fading away, consider this: a staggering 92 million Americans are smokers or former smokers. And they're all at risk of getting lung cancer.

So there's a crying need for a test that could identify lung cancer early, when it might be cured. This new study says CT screening can do that. It looked at more than 50,000 people who'd smoked heavily.

Dr. William Black of Dartmouth Medical School says the study's results, a 20 percent reduction in lung cancer deaths, shows this kind of cancer screening is about as effective as mammography.

Dr. WILLIAM BLACK (Dartmouth Medical School): In the same ballpark. Yeah.

KNOX: The reason it's only a 20 percent reduction in lung cancer deaths is not because it misses many cancers.�

Dr. BLACK: The reason you don't expect 100 percent is because you expect some of the cancers you detect will have already spread by the time you pick them up.

KNOX: The next question is, what should people at risk for lung cancer do now that these results are out? Some think people with a smoking history should get CT screening tests, even if they have to pay for them on their own.

Dr. CLAUDIA HENSCHKE (Mount Sinai Medical Center): They should have that conversation with their physician and decide whether it's worth their while to be screened.

KNOX: That's Dr. Claudia Henschke of Mount Sinai Medical Center in New York. She's the leading advocate for CT lung screening. She has no doubt that smokers and former smokers should be asking their doctors about this test.

Dr. HENSCHKE: I think they can have those discussions now.

KNOX: But Peter Bach, of Memorial Sloan-Kettering Cancer Center in New York, disagrees.

Dr. PETER BACH (Memorial Sloan-Kettering Cancer Center): If the question is, you know, is it ready for prime time or what should we tell people who have a smoking history to do today or tomorrow, I think, you know, as unsatisfying as this answer is, it's a little too early to know that.

KNOX: Bach points out that for every 300 people screened with CT scans, one person will be saved from dying of lung cancer. That's what the new study shows. But at least 25 percent of people who get the test will have a false alarm.

That is, screening will detect something suspicious in their lung that requires more tests, sometimes including needle biopsies and chest surgery. But most of these suspicious lumps will not be lung cancer.

Bach says the risk that this test will give a false positive result is about 100 times higher than the chance that it will keep someone from dying of lung cancer.

Dr. BACH: And so we're all going to have to look very carefully at how that tradeoff works for different groups of patients so that we can provide good advice to doctors and patients who are considering this.

KNOX: William Black of Dartmouth says there's a lot to figure out.

Dr. BLACK: Well, yeah, there's lots of questions. We know it can work. OK? Now that it works, how do we do it and in whom?

KNOX: Black says even after experts decide who should be at the head of the screening line, that's just the beginning.

Dr. BLACK: How long do we screen these people for? How often do we screen them? How exactly do we interpret all the findings? What do we do about people who are little bit older or a little bit younger? There's tons of questions that have to be answered.

KNOX: The work to answer those questions starts now. But you can bet it'll stretch on for months and years.

Richard Knox, NPR News.

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