Today's announcement from the National Cancer Institute that the National Lung Screening Trial reduced deaths from lung cancer by 20% is exciting and important news. However, as always, there is more to the story that is yet to be told. And before we consider this a slam dunk in favor of screening, it is important that all of us understand what this trial has shown--and what it has not.
The background of the trial is that starting in 2002 the National Cancer Institute along with other collaborating organizations--including the American Cancer Society--recruited 53,000 current and former heavy smokers to a trial designed to show whether or not low dose helical chest CT scans reduced deaths from lung cancer compared to single view chest x-rays.
It is important to understand who participated in this trial: Current and former smokers had to have at least a 30 pack year history of smoking cigarettes. A pack year means smoking one pack a day for one year, so 30 pack years could be 3 packs a day for 10 years or one pack a day for 30 years. Former smokers who met those criteria had to have stopped smoking within 15 years of the time they entered the trial. Men and women were accepted, but had to be between the ages of 55 and 74. Special efforts were made to increase minority participation.
The design of the study was for these participants to get either a single frontal chest x-ray or a lung scan every year for three years. If anything was detected on the x-ray or CT, the participant was referred back to their primary physician for further follow-up. Sometimes that follow-up included another lung scan, or sometimes even surgery to evaluate the lesion on the scan.
In October, the committee that was monitoring the study concluded that the end-point had been reached. They notified the National Cancer Institute of that fact, and today the NCI held a press conference to announce the results. The study has been stopped, and the participants have also been advised of the results. The participants will continue to be followed, with further updates coming in the future. For now, the data has not been completely analyzed, and further work will be done to look at the study information with plans to publish the results in several months.
As noted, the study showed that death rates from lung cancer decreased 20% in heavy smokers who had a lung CT compared to those who had a chest x-ray. In addition, the overall death rate from all causes in people who had CT scans was 7% lower compared to those who only had the chest x-ray.
The reasons for these differences is not clear, according to the NCI investigators who participated in today's press conference. For lung cancer, the assumption is that CT scans led to earlier diagnosis and earlier treatment, but that has not been confirmed by careful data analysis at this time. For the "all-cause" reduction, the presenters indicated they are not certain why that happened, and will be looking at that finding in more detail.
As always, there are some cautionary notes that all of us must keep in mind when considering the implications of this report.
First and foremost, this is a "quick report" which is important for public health, but the data have not yet been fully evaluated. There is a reasonable expectation that the 20% number is "real," but I have learned from past experience that drawing quick conclusions from press conferences can be a bit risky. More time is needed for the complete data analysis, presentation and publication. And perhaps as important is the opportunity for those knowledgeable in these issues to digest the report, make their own analyses and offer us their thoughts.
Second, this is not a group of people who are generally in good health. People who have been heavy smokers usually have other serious medical problems such as heart disease, stroke, and advanced lung disease. Finding a nodule in the lung that may require chest surgery is not necessarily going to help people who have advanced medical diseases, such as those noted above. And the risks of treating people in that group can be substantial, even deadly.
In this study, despite those concerns, the death rates declined. But if you have advanced lung or cardiac disease, pursuing lung screening may be risky in your situation.
Above all, I suspect the data will show that a number of people still died from lung cancer. This study does nothing to advance our treatment of lung cancer, which remains far from satisfactory. And it does nothing for people who are not smokers and develop lung cancer. And it doesn't say anything to us about people at lower risk of lung cancer, such as everyone who does not meet the criteria outlined for the study.
So if you are a younger person, who has "only" smoked a pack a day for 20 years, this study tells you nothing. And if you are a non-smoker who works in a heavy smoking environment, such as a bar in some communities that don't have smoke-free laws, this study says nothing to you.
We also don't know from this study what the ideal screening program is for lung cancer. Unlike colon cancer, where we have several studies and science that helps us define screening intervals, this study doesn't tell us for the larger population of smokers how often they should be screened, when they should start screening or for how many years they should be screened.
With all of that information and uncertainty, what should you do?
The American Cancer Society does not have a formal recommendation at this time based on the results of this study. Remember, this is a very preliminary report and more information will be forthcoming. As will others, we will carefully examine the information once it becomes available and at that time will probably say something more definite. But for now we just don't have enough information.
Having said that, if you are someone who meets the criteria similar to people who participated in this study, then you may want to consider getting a scan. But before you do that, it would be wise to have a conversation with your health professional and consider whether screening is right for you. You should especially consider your current health status and answer the question if something is found, would you be willing and able to get treated with surgery, radiation therapy, and chemotherapy, either alone or in combination?
You should also be aware that there is a pretty good chance that somewhere along the line you may find a lesion in the lung that is not cancer. It has happened to me, and I am a non-smoker--so I know what the experience can be like, including all of the "follow-on" tests that would be recommended.
Finally, you should determine whether or not your insurance will cover the test if that is a factor for you. Right now, Medicare does not cover the test. They apparently are going to look at the data as it becomes available, but for right now the cost is yours.
So, as I said in the beginning: this is good news, but be aware and be cautious. And stay tuned, because there is clearly more to come.
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