Author speaks out about controversial lung cancer study
From the January-February ACP Observer, copyright © 2007 by the American College of Physicians.
By Stacey Butterfield
Claudia I. Henschke, MD, is the lead author of a new study on lung cancer screening. Dr. Henschke and her colleagues in the International Early Lung Cancer Action Project performed CT screens on more than 31,500 people who were at high risk for developing lung cancer. Although screening for lung cancer is not currently recommended by national organizations, Dr. Henschke's work has provided interesting new data on the controversial issue of screening for lung cancer in high-risk patients
Data were gathered from more than 30 hospitals around the world and sorted at a coordinating center at Weill Medical College of Cornell University, where Dr. Henschke is a professor of radiology.
A CT scan with a small cancer in the right lower lobe (shown left) and a close up of the cancer (shown right).
The results, published in the Oct. 26 New England Journal of Medicine, found that CT screening resulted in a diagnosis of lung cancer in 484 participants, 85% of them with clinical stage I cancer. The estimated 10-year survival rate for the 484, regardless of stage and treatment, was 80%. Among the 302 Stage I participants who underwent surgical resection within a month of diagnosis, the survival rate was 92% while all those in early stage without treatment died within five years.
Dr. Henschke has been a long-time advocate of lung cancer screening and had previously published research on CT scanning. The new study brought the issue into the public eye, with some critics still questioning the merits of CT screening.
ACP Observer recently spoke with Dr. Henschke about the impact of the study and the future of lung cancer screening.
Q: Based on your study results, who should be screened for lung cancer?
A: Typically somebody who's at least 50 years old with a history of at least 10 pack years. That means, for example, one pack a day for 10 years or two packs a day for five years. The risk for lung cancer starts increasing as you age. For a patient at age 50 with a 10 pack year smoking history, whether the patient is a current smoker or former smoker, the physician could discuss with the patient the benefits of doing CT screening.
Q: In your opinion, what should be the procedure for screening?
A: The patient should get the screening at a place that has experience in doing it. Screening requires that you do it in a well-controlled setting. We've learned that from breast cancer screening. You need the right type of equipment. You need the training and the expertise and you need to make sure that there is follow-up.
Q: Do you think your study results should cause CT scanning to become standard for lung cancer screening?
A: We think our paper provides compelling and convincing evidence. Initially we had published a paper in The Lancet in 1999 that showed we could find early stage lung cancer in 85% of people, whereas typically it's found in less that 15% of people. That's a huge shift that we already demonstrated. Many people have been getting screened since that time. But you really need to also look at the long term follow-up of those people who are diagnosed early.
Q: According to your research, how might early screening affect long-term survival of lung cancer patients?
A: Our study confirmed that we could find lung cancer early in 85% of the people who had a lung cancer detected and that when you find it early and treat it promptly, the 10-year survival rate is 92%. Now that in itself is not that surprising because there have been prior studies, although some much smaller. It's been known for a long time that finding lung cancer early allows you to treat it far more effectively, and that a high percentage of the patients can be cured.
Q: How cost-effective is the screening?
A: It's a highly cost-effective process if it's done appropriately. The typical charge for a low-dose CT scan is about $300. The actual cost to the hospital is less. Early treatment is about half the cost of late stage treatment in the U.S., according to the Medicare data. In our study of high-risk people (former and current smokers, 60 years of age and older) for lung cancer, we found that considering all tests resulting from the screening including surgery, CT screening costs about $2,500 per life-year saved.
Breast cancer screening costs about $20,000 to $30,000 per life-year saved. Pap smear screening is about the same. Colonoscopy costs more than $100,000 per life-year saved. So CT screening for lung cancer is more cost-effective, if properly done, so you don't have too many additional tests or unnecessary biopsies, which we showed in our paper you didn't need to have.
Q: In our opinion, why isn't CT scanning more accepted as a screening method?
"With lung cancer you can target the high-risk person much better than you can with any of the other cancers."
—Claudia I. Henschke, MD
A: I don't know why. Breast cancer screening was ultimately justified on the basis that mammography finds early cancer and earlier treatment is better than later treatment. With lung cancer you can target the high-risk person much better than you can with any of the other cancers.
It must be somehow the stigma attached to it, that you did it to yourself. Also, some smokers quit when the Surgeon General said you should quit—what they don't realize is they remain at high risk for lung cancer for some 20 or 30 years, and their risk never goes down to the risk of a lifelong nonsmoker.
Today we are finding more cancers in former smokers. To not have screening available to former smokers seems to me not very fair because by stopping smoking they're following recommendations. Their risk of heart disease goes down quite rapidly. Therefore they live longer and have more risk of dying of lung cancer.
Q: Do you think there should be a randomized controlled trial of CT screening?
A: We don't think so. Our study addresses the diagnostic performance of CT in finding early lung cancers—85% in Stage I—and then whether early treatment is better than no or late treatment. But nobody in the world can randomize people to early treatment and late treatment because everybody knows the consequences of treating late stage lung cancer. However, in those in whom overdiagnosis is truly suspected, it would be possible to do this randomization. The randomization should be done at time of treatment, either immediate treatment or later treatment. So we do have a control arm.
Q: What is the next step in your research?
A: There are still unanswered questions. We think it's very important to combine a screening program with smoking cessation advice. We've shown that we're very effective at combining smoking cessation programs with screening. We have a very good one-year quit rate.
Also, right now, we say it [CT screening] should be done every year. But let's say somebody stopped 20-30 years ago. How long do we really need to screen them? Those are questions that are still to be answered.
We have also just been funded for a grant to evaluate whether screening makes sense in the never smoker who has been heavily exposed to secondhand smoke. We're going to go through the same kind of assessment that we've gone through for smokers or former smokers.
Hopefully it won't take us 14 years. Because we've shown that if you find lung cancer early and treat it early you do very well, so now it should be enough to show how many [tumors] you find and how early you find them in these other groups.
The information included herein should never be used as a substitute for clinical judgment and does not represent an official position of ACP.
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