CT Scans Reduce Lung Cancer Deaths
Study finds annual CT scans of current and former smokers over 55 lower risk of death by 20 percent
Yearly CT scans of middle-aged and older smokers — and former smokers — can reduce the risk of death from lung cancer by 20 percent, according to an eight-year, landmark study funded by the federal government. Health experts say the study results represent a historic leap forward in cancer detection that could save thousands of lives each year, although at considerable cost.
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CT scans of smokers and former smokers reduced deaths from lung cancer by 20 percent.
"We have finally demonstrated that most lung cancers can be detected early," says Christine Berg, M.D., of the National Cancer Institute, the lead author of the study.
Lung cancer kills far more Americans than any other type of cancer. It strikes more than 220,000 people each year and kills about 160,000 of those, more than colon, breast and prostate cancers combined.
Previously, doctors only ordered computed tomography scans (CTs) or x-rays for smokers who complained of symptoms, such as coughing up blood. Health experts say this study is likely to lead to a push for widespread screening using CT scans on millions of older smokers. "It's a game-changing trial for lung cancer screening," says Harold Sox, M.D., a professor emeritus at Dartmouth Medical School who wrote an editorial commenting on the study, released online Wednesday in the New England Journal of Medicine.
But even some experts who hailed the study's results question whether the research will lead to costly, unnecessary screening and procedures on men and women who are not really at high risk. Biopsies and lung surgery on older people can be dangerous, even deadly.
For 30 years, researchers and cancer doctors watched in frustration as study after study designed to screen for lung cancer failed. Even when x-rays could find tumors in lungs, they didn't save lives because it was too late. As CT scan technology improved, Berg and other researchers thought the scans might be able to catch lung tumors at an early enough stage to improve survival.
They tested that theory in this National Lung Screening Trial with more than 53,000 people ages 55 to 74 who had smoked at least one pack a day for 30 years or two packs a day for 15 years. They also included heavy smokers who had quit smoking within the last 15 years. Older former smokers who quit more than 15 years ago were not included in the study, because over the years their risk of lung cancer drops considerably.
Next page: Dramatic CT scans results stop trial early »
Participants at 33 sites received either a low-dose CT scan or a chest x-ray for three years and were followed for five. The results were compelling enough that researchers stopped the trial early in November and released some information about the study. But the complete statistics and results were not released until Wednesday.
Frank Detterbeck, M.D., surgical director of the Yale Thoracic Oncology Program, says now government groups, such as the U.S. Preventive Services Task Force, and nonprofit cancer groups will delve into the numbers and create guidelines for how doctors should interpret the results.
"We need to take these results very seriously," Detterbeck says, and consider how to "save the thousands of lives that we have the potential to save."
About 7 million Americans fit into the group studied in the trial, but there are 94 million current or former smokers and many more with other risks, such as exposure to secondhand smoke.
Detterbeck chairs a committee of experts working to create guidelines in the next several months to help doctors apply the results of the study to their patients.
While the results are compelling enough to warrant the CT scans, Detterbeck says, at the same time it's crucial to carefully design the recommendations so that doctors understand how to interpret the findings.
The researchers, he points out, also saw a large number of spots on the scans that weren't dangerous, leading to more scans, and even biopsies and surgery. About a quarter of all the scans found some abnormality but nearly all of them turned out to be benign. The scans also found cancers that surgeons then removed that might not have been harmful.
"If everybody who has a little finding on the scan starts to have a biopsy, then we may do a lot of harm," Dedderbeck says.
And as government seeks to reign in rising health cost, even one of the experts who helped design the study says there are hard decisions to be made before the country commits to a new screening that could cost billions of dollars.
"There are not unlimited health care dollars," says Edward Patz Jr., M.D., a professor of radiology at Duke University Medical Center and an investigator who helped design the study. "We have to make some decisions once we have the data whether this is really worth it or not."
Next page: Is this test really necessary? »
Some also worry that medical professionals more interested in profits than evidence could frighten younger people or those who aren't heavy smokers into believing they should get a CT scan as well. Although most insurance programs and Medicare wouldn't cover an initial screening, once a scan finds something suspicious, insurance and Medicare will pay for further tests, biopsies and even surgery. Since a large percentage of scans will show something suspicious, hospitals or radiology centers stand to make money from the procedures.
"It's a gateway to having new patients," says Peter B. Bach, M.D., a lung specialist and epidemiologist at Memorial Sloan-Kettering Cancer Center in New York City, who warns of "the hucksterism that will surround" the findings. "The concern is that people will use this study and overblow the benefits, seriously soft-pedal the risk and start pushing this on people who are not at high risk," he says.
Sox says for all of these "false positives," there were relatively few biopsies and surgeries in the study, most likely because it was conducted with top doctors and technology at large medical centers.
But he adds that in order to duplicate the results of this study and reduce deaths from lung cancer in community practice, "you've got to have people who are really experienced, or else everybody has got to go to a big medical center where they do a lot of interpretation of these scans."
Some large medical systems are already poised to launch screening programs.
Based on the results of this trial, the University of Pittsburgh Medical Center, for example, will start advertising a new clinic offering lung cancer screening in the next few weeks aimed specifically at the group studied — those ages 55 to 74 who are smokers or have smoked within the past 15 years. For $200, people receive an hour of education about the scans and information about smoking cessation and a low-dose CT scan interpreted by a radiologist who will interpret the results and consult with a specialist.
"The results of this study are very important, suggesting that many Americans who smoke should not only quit smoking, but also undergo lung cancer screening with CT scans, both of which will reduce lung cancer mortality rates," says Mark Gladwin, M.D., chief of the division of pulmonary, allergy and critical care medicine at Pittsburgh. Other hospitals, medical centers and radiology clinics are sure to follow suit. Scans cost between $300 to $1,000, according to the National Cancer Institute, but costs can go much higher than that in some parts of the country.
Bach of Sloan-Kettering says it might be more worthwhile for the U.S. health care system to channel money into smoking cessation programs, which can prevent or reduce lung cancer risk, rather than funding the newest technology to find and remove the cancers after they've taken root.
Quitting smoking is a much more effective way to cut your risk of dying from lung cancer, he says. And, he adds, quitting smoking also reduces the risk of death from other "major killers" linked to smoking, including heart disease and other cancers.
Elizabeth Agnvall is a contributing editor of the Bulletin.