Lung cancer kills more Americans than any other cancer. Each year about 190,000 people are diagnosed with the disease; 158,000 of them die from it. No wonder doctors hope to find an effective way to screen for the disease, just as they use the Pap smear to detect cervical cancer. Last fall researchers reported in the New England Journal of Medicine that early detection of lung cancer through computed tomography (CT), when followed by surgery within one month, results in a 10-year survival rate of 92 percent. That was big news for America's 92 million current and former smokers, who are at increased risk for a disease that tends to develop silently, with symptoms such as chest pain and coughing that often don't appear until the cancer is advanced.
At the time, officials at the National Cancer Institute were cautious. Before recommending screening, they want proof that screening actually reduces the number of deaths from lung cancer. To that end, the NCI began its own randomized, controlled trial in 2002, which should be completed in 2009.
The wisdom of that wait-and-see approach was confirmed this week with the release of a new report in the Journal of the American Medical Association (JAMA) that suggests early screening may be a bad idea. Researchers looked at 3,246 asymptomatic current or former smokers screened for lung cancer and found that screening did not reduce deaths from lung cancer, even as it dramatically increased the number of patients undergoing surgery. An editorial accompanying the study asks, "How is it possible that two large studies published within six months of each other could lead to such dramatically different conclusions about the effectiveness of CT screening?" The most probable explanation: the new study measured mortality whereas the fall study measured survival. NEWSWEEK's Karen Springen spoke with the lead author of the new study, Dr. Peter B. Bach, a lung specialist and epidemiologist at the Memorial Sloan Kettering Cancer Center in New York. Excerpts:
NEWSWEEK: Your study says early screening detects more cancer—but doesn't necessarily reduce deaths from the disease. Why?
Dr. Peter B. Bach: It looks like the screening test is very good at picking up very small growths in the lungs, some of which look like cancer when you biopsy them or take them out. But they're probably not the cancers that are going to go on any time soon and cause health problems. Despite finding many early cancers and removing them with surgery, we weren't able to prevent patients from dying of lung cancer. In fact, it looked like CT was missing the cancers that caused death and only picking up those that grew very slowly and didn't pose much of a threat. Over the five years of the study, there were 38 deaths from lung cancer, and that's exactly how many we would have seen if we had not done any screening.
What's the take-home message? Is it that doctors should stop giving early CT scans, and patients should stop asking for them?
Doctors should definitely not be offering any early-detection test that's not proven to be beneficial. There's no established approach for testing for lung cancer, and there's no professional organization that recommends screening with CT scan. There's no evidence that treating those early cancers provides any benefit to patients. Meanwhile, there are lots of risks, including the risk of extra biopsies that are done to evaluate abnormalities, and the risk of the treatment of the small modules that don't seem to pose much of a threat.
You found a 10-fold increase in lung-cancer surgeries resulting from screening. Do you think some of these patients should not have been operated on?
This is one of those tricky things. Once you know about these cancers, it's inevitable that you perform surgery and remove them. There is every possibility that with a larger study, we will be able to see that when you screen people for lung cancer, you do reduce, to a small extent, their risk of dying from lung cancer. Whether or not the extent of the reduction is enough to make up for the biopsies and the rest of it is something that can only be determined with a large study. If anything, our study looked like the studies of chest x-rays decades ago. The screening didn't save any lives.
Who, if anyone, should get an early screen?
There is a lot of excitement about CT screening because CT is more sensitive than chest x-ray. It really looks from the study as if we're missing the cancers that are going to go on to cause death. I think they're moving faster, but that's just a hypothesis. We have done a very good job in the public health community of sending a message that cancers can be found early, so you should go get checked. And if you go get checked, and they find the cancer early, that's great. That's true in breast cancer, cervical cancer and colon cancer, but that doesn't necessarily mean it's going to be true for all cancers. Our model for them—catch it early, save a life—may not apply in every case. We have to be very cautious before we take healthy people, who have nothing wrong with them, and ask them to have a test that involves radiation and possible biopsies. About 12 percent of people who have a scan end up having a biopsy. And they're virtually all negative. And every once in awhile when we do one of these biopsies, somebody gets a collapsed lung.
What about when the biopsies reveal lung cancer?
The whole idea of screening is to find these small growths in the lung that are cancer and take them out. Here's the problem. Our study, which is consistent with many studies that have been done strongly suggest that these strong things that look like cancer when you biopsy them are not very dangerous at all. They're probably quite slow growing or maybe even haven't developed the characteristics they need to cause the person to be sick and to kill them. Right now we don't know what the significance of these small growths are, but we're certain they don't constitute the cancers that will rapidly progress and kill people because we found almost 100 extra early cancers and 100 extra surgeries, and we didn't prevent a single death from lung cancer over almost five years of study. At the end of the day, we don't know what these nodules mean. Any time we do a lung-cancer surgery to remove a cancer and take out a lobe of the lung, the risk that somebody dies from that surgery is about 4 percent. That may not sound like a high number, it's about 1 in 25, but it's a high number if you're not sure what the benefits of the surgery are. In our study, screening people increased the rate of these surgeries 10 times. So we better be very sure that what we're finding is going to go on to be lung cancer and that the treatments we're applying are beneficial, because they certainly have risk. ... Right now the data from our study suggests that this isn't going to help people, and we're not going to save people's lives by doing this. We're not going to find the cancers that are going along quickly and claiming people's lives. We're going to treat people a lot more, and meanwhile, at least in our study, we didn't save a single person's life.
What about the financial issues—a $300 test and then an operation that costs thousands?
In my mind, how we pay for this test and whether people pay for it or whether insurance companies pay for it is something that needs to be settled after we determine whether or not it's beneficial. This is an intervention. We're offering this to people. Right now our study suggests they won't benefit, and they could be harmed. I don't care if it's free. It's not an issue of financing. It's an issue of health. It doesn't matter what it costs. There's no question in my mind that people shouldn't be getting screened for lung cancer. The American Cancer Society doesn't recommend it. The National Cancer Institute doesn't recommend it. Our study gives you at least one of the reasons why. It's not only unproven, it's potentially harmful. The reason they shouldn't go is it may hurt them, and it probably isn't going to help them. Not because it costs $250 or $400. We wouldn't encourage anyone to get it, even if it were free.
Dr. Claudia Henschke's International Early Lung Cancer Action Program study in the New England Journal of Medicine last fall said that early detection followed by surgery within one month resulted in a 10-year survival rate of 92 percent. Why are your results so different?
Our results are not different. Our interpretation is different. We found cancers, just like they did, that were small. But the key difference is that we actually counted how many people died of lung cancer over the study and asked whether or not it had been reduced by all the early detection and treatment, and the answer is no. That study was reported as a very large study. But the reality is they followed about 400 patients for about three years. All of these patients were patients with very good prognosis lung cancer and may not have caused any trouble if they'd been left alone. We followed them to see how many got advanced cancer and asked if that had been reduced by screening. So Dr. Henschke's study gave some preliminary idea by studying about 1 percent of people they'd screened and looking at the survival of those people. They just asked about survival in that 1 percent of people. We asked about everybody. The question in screening you'd want to ask is, will I be better off if I have it than if I don't.
Should we all just continue to wait for the results of the randomized, controlled National Lung Screening Trial by the National Cancer Institute?
That's absolutely what you should do. I don't want people to believe that screens will save their life, and even more important, we don't want people to think that if they smoked for a long time or continue to smoke, if they just go get a CT scan, and there's nothing going on with the CT scan, they're fine. We had plenty of people in our study who looked fine in the CT scan—and then went on to develop lung cancer. Having a negative CT scan doesn't mean you're OK. It's really disappointing for all of us. We would love to say we have a new test for preventing lung cancer, but this isn't it.