Lung cancer kills more Americans every year than any other kind
of cancer, mainly because doctors donĦt have a reliable way of finding
it early. 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 U-M Comprehensive Cancer Center (CCC) and other
study centers across the country soon will begin making pictures
of the lungs of smokers and ex-smokers, using either a chest X-ray
machine or a CT ("cat") scanner. Then, theyĦll track participantsĦ
health for several years, looking yearly for signs of lung cancer.
By the end of the study, theyĦll be able to tell whether regular
chest X-rays or CT scans had any effect on the participantsĦ lung
cancer detection and mortality rates. This might help determine
whether all 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 Dr. Ella Kazerooni, director
of thoracic radiology at U-M Health System and a member of the CCC.
"WeĦre looking for men and women aged 55 to 74, 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 needed because of the huge death toll that lung cancer
takes every yearabout 157,400 Americans, more than the number that
die from prostate, breast, colon and ovarian cancer combinedand
because of claims that have been made about the power of new spiral
CT machines to detect lung cancer, Kazerooni says.
"In the last few years, CT scans have been shown to pick up small
cancers, and itĦs become much easier to see those small cancers
with a CT scan than with a chest X-ray," she says. But, she adds,
there isnĦt enough proof to say that CT scans help reduce the lung
cancer death rate.
Some doctors worry that, because normal tissue can look suspicious
on a high-quality spiral CT scan, the scans will cause needless
worry and will 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.
Participants will be assigned to chest X-rays or CT scans at random.
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 smoking cessation programs.
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, which is
enough time to see if there are death-rate differences between the
two groups. If an X-ray or CT scan finds a suspicious area on a
participantĦs lungs, he or she will be referred for further testing
and, if needed, treatment.
Despite lung cancerĦs wide reach and deadly toll, doctors donĦt
have the same kind of detection systems for it as they have for
other, less common or less deadly cancers.
"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."