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CT Screening Cuts Lung Cancer Mortality; Raises Policy Questions

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Exciting Results, but Not Ready for Prime Time

This is an exciting

study that does show an impact on mortality, which has not been a screening

result from previous studies. What it doesn’t tell us exactly is: What does

this mean from a policy standpoint?

We need to look at a lot

more to see what’s the best model with this kind of screening and when this is

screening appropriate. I think the authors of this study were right to say that

this is a very positive result and it’s helpful … but that the best way to

implement this in day-to-day practice still is not completely resolved. There’s

a lot more work to be done in that regard.

One message that is still

very clear is that if you don’t want to die from lung cancer, you need to stop

smoking or never start smoking. This still has to be foremost in our public

health preventative message.

The study results do help

by saying that screening can have a role in day-to-day practice. The fact that

these patients were treated in a community setting showed that … the process

for diagnosing lung cancer can be handled by community physicians. I’m a

pulmonary physician. So when I sit down with patients who have the risk of

smoking, and we talk about what is the role of getting a low-dose CT scan for

screening, I think I have a lot more information to help both me and the

patient to decide whether this is beneficial to them versus a risk.

In the past, with CT

screening there was certainly risk from the radiation and risks for having

unnecessary procedures done, but no real proven benefit that we were going to

impact mortality if we found an early cancer. The study results do add value on

a day-to-day basis.

We just don’t know whether

it’s something that should be applied to everybody. Another question is whether

there are there markers that might help in this group of individuals to

identify who is at high risk for fast-growing tumors or for slow-growing tumors

Are there biologic markers that we can find with a blood test that might add to

this information to help us sort out who would benefit from screening or not?

[Other questions to

answer] from these data or from other ongoing studies include: Are there

subgroups of this 55- to 74-year-old population that are at higher risk? Are

there individuals who with less frequent screening can do just as well? Are

there individuals for whom more screening is necessary? The population looked

at [in the study] was a narrow window of high-risk individuals … It represents

about 7 million people out of the 94 million current and former smokers that we

have in this country.

We may even be able to

look at genetic markers at some point in the near future to determine who is at

higher risk and that will help us better identify who needs to be screened. I

think biomarkers and genetic markers all could be added to the formula when

we’re trying to decide what the best risk population to be screened is.

Screening tools work best when the screening population is well defined.

So now we have evidence

that screening in general can have an impact on disease. Unfortunately, prior

to this, lung cancer was diagnosed too late to make a big impact for most

patients. In lung cancer, an earlier diagnosis hopefully impacts mortality.

Lung cancer could become a curable disease if it’s found early enough to be

completely resected.

Dr. Albert A. Rizzo is

chair-elect of the American Lung Association board and chief of Christiana

Care’s pulmonary and critical care medicine section in Newark, Del.

He has no conflicts of interest.


 

FROM THE NEW ENGLAND JOURNAL OF MEDICINE

In an accompanying editorial, Dr. Harold C. Sox, professor of medicine at the Dartmouth Institute in Hanover, N. H., agreed with the investigators’ reservations. In particular, the cost effectiveness of low-dose CT screening for lung cancer must be analyzed, he said: "Policy makers should wait for cost-effectiveness analyses to determine the amount of overdiagnosis in the NLST, and, perhaps identification of biologic markers of cancers that do not progress."

In addition, "it may be possible to define subgroups of smokers who are at higher or lower risk for lung cancer and tailor the screening strategy accordingly," he said. "The findings of the NLST regarding lung-cancer mortality signal the beginning of the end of one era of research on lung-cancer screening and the start of another. The focus will shift to informing the difficult patient-centered and policy decisions that are yet to come."

Dr. Sox also noted that "overdiagnosis is a problem because predicting which early-stage cancers will not progress is in an early stage of development, so that everyone with screen-detected cancer receives treatment that some do not need," he wrote in an accompanying editorial (doi: 10.1056/NEJME1103776).

All but two of the NLST study authors reported that they have no relevant financial relationships. Jonathan D. Clap reported having financial interest in Human Genome Sciences. Constantine Gatsonis, Ph.D., is a consultant for Wilex AG, Mela Sciences, and Endocyte Inc., has received speaker fees from Bayer Health and payment for education development by the Radiologic Society of North America. He also has invested in the Vanguard Health Fund. Dr. Sox had no conflicts.

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