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Looking at Lungs: New national study will test ways of finding lung cancer early
A University of Michigan Health Minute update on important health issues
U-M Health System seeking 1,000 smokers and former smokers to take part
originally posted September 18, 2002
ANN ARBOR, Mich. - Lung cancer kills more Americans every year than any other kind of cancer - mainly because doctors don't have a reliable way of finding it early, when treatment has the best chance of working. Now, a new nationwide study will test two different methods of looking for tiny lung tumors, to see if either approach can help catch cancer early and reduce the death rate among patients.
Doctors at the University of Michigan Comprehensive Cancer Center and other study centers across the country will soon begin making pictures of the lungs of smokers and ex-smokers, using either a chest X-ray machine or a CT ("cat") scanner. Then, they'll track participants' health for several years, looking yearly for signs of lung cancer.
By the end of the study, they'll be able to tell whether regular chest X-rays or CT scans had any effect on the participants' lung cancer detection and mortality rates. And that might help determine whether all American smokers and ex-smokers should get their lungs scanned regularly - or whether scientists need to keep looking for better ways of finding lung cancer in its treatable early stages.
"The trial will recruit 50,000 patients, of which 1,000 will be specifically recruited here," says Ella Kazerooni, M.D., M.S., director of thoracic radiology at UMHS and a member of the U-M Comprehensive Cancer Center. "We're looking for men and women aged 55 to 74 years, who are current and former smokers. Former smokers must have quit within the last 15 years." Smoking is by far the biggest risk factor for lung cancer, causing 87 percent of cases.
The study is badly needed because of the huge death toll that lung cancer takes every year - about 157,400 Americans, more than die from prostate, breast, colon and ovarian cancer combined - and because of claims that have been made about the power of new spiral CT machines to detect lung cancer, Kazerooni explains.
"In the last few years, CT scans have been shown to pick up small cancers, and it's become much easier to see those small cancers with a CT scan than with a chest X-ray," she says. But, she adds, there isn't yet enough proof to say that CT scans help reduce the lung cancer death rate. Currently, that rate is 85 percent after five years.
Some doctors even worry that, because normal tissue can look suspicious on a high-quality spiral CT scan, the scans will cause needless worry and even lead people to have tests or surgery that could harm them. To settle the debate, the National Cancer Institute and the American College of Radiology Imaging Network are sponsoring the study, called the National Lung Screening Trial.
The study is designed to be as scientific as possible, to make sure that the results will hold up under scrutiny and be good enough to guide public health recommendations.
Participants will be assigned to either chest X-rays or CT scans by random chance - like the flip of a coin. They must have no history of lung cancer, but they must be heavy smokers, or former heavy smokers. The risk of lung cancer goes up with the number of cigarettes smoked per day. Participants who smoke and want to quit will receive referrals to stop-smoking programs.
All participants must be in the age group - over 55 years old, and younger than 75, when they begin the study - that has the highest risk of lung cancer. The researchers will make sure to include people of all races, incomes and educational levels, so that they can look for patterns of lung cancer occurrence and survival in different populations. Currently, statistics show that African-Americans and people with lower incomes and educational levels have a higher risk of getting lung cancer, but the reasons for these differences aren't clear.
Participants will have spiral CT scans or X-rays each year for the first three years, and will be surveyed about their health and quality of life every six months for up to eight years - enough time to see if there are death-rate differences between the two groups. If an X-ray or a CT scan finds a suspicious area on a participant's lungs, he or she will be referred for further testing and, if needed, treatment.
Some participants, including all 1,000 enrolled at UMHS, will be asked to give blood, urine and phlegm samples. These will help scientists look for clues to what makes people vulnerable to lung cancer, and perhaps allow them to find tiny "biomarkers" common to many cancer patients that could someday be used to test for lung cancer.
Ultimately, Kazerooni and the other study leaders hope they will help in the search for an effective way to provide early, reliable detection of lung cancer. They know that millions of American smokers and former smokers are likely to develop lung cancer sometime in their lives, and they want to help them have a better chance of survival.
"Unfortunately, the majority of people with lung cancer are diagnosed when the disease is advanced, making a cure very difficult," she explains. "Many lung cancers are found when people have symptoms, like a new or different cough, or when they start coughing blood. Unfortunately, when lung cancer is very small, say the size of your fingernail, it's very hard to pick up, and doesn't make symptoms." But that's when treatment has the best chance to work.
Despite lung cancer's wide reach and deadly toll, doctors don't have the same kind of detection systems for it as they have for other, less common or less deadly cancers. Such systems, using medical imaging tools, blood tests or hands-on techniques, are called screening tests.
"People may be familiar with mammography, used to screen for breast cancer, or physical exams, blood tests and endoscopy that are done to look for prostate cancer or colon cancer," Kazerooni says. "But currently, there is no way to screen for lung cancer."
Kazerooni and her colleagues have to wait for the evidence to come in, but they hope the study will show that either chest X-rays or spiral CT's are successful in finding early lung cancers, and that such detection reduces lung cancer mortality - as well as showing any limitations the techniques may have.
"If this is shown to be a benefit, people at risk around the United States would be eligible to have this done clinically - similar to the way they may currently undergo mammography," or prostate PSA testing, Kazerooni predicts.
You may be eligible for the study if you:
To learn if you are eligible to participate in the study, call 800-4-CANCER (800-422-6237) between 9 a.m. and 4:30 p.m. weekdays, or visit www.cancer.gov/nlst.
The Henry Ford Health System in Detroit is the only other NLST center in Michigan, and is participating in the PLCO (Prostate, Lung, Colon & Ovary) wing of the NSLT study, which will focus on several types of cancer including lung cancer.
Facts about lung cancer: