WEDNESDAY, Oct. 26 (HealthDay News) -- Using chest X-rays to
screen for lung cancer doesn't prevent deaths from the disease, a
new study finds.
"There really was no benefit of the screening," said study co-author Dr. Christine Berg, chief of the early detection research group at the division of cancer prevention at the U.S. National Cancer Institute. "We detected some of the cancers a little earlier than we would have, but not early enough or in large enough numbers to really have an impact on lung cancer mortality."
Experts noted that the results of the large randomized clinical
trial should put an end to any lingering questions about whether
X-rays are useful in lung cancer screening. Recent research has
indicated that CT scans are more effective at spotting malignancies
The study involved more than 150,000 never smokers, former
smokers and current smokers aged 55 to 74 taking part in the
Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial.
Half of the participants, including smokers and nonsmokers,
underwent annual chest X-rays for three or four years between 1993
and 2001; half did not get screened.
During 13 years of follow-up, similar numbers of people in both
groups were diagnosed with lung cancer -- 1,696 in the screened
group and 1,620 who were not screened.
There were 1,213 lung cancer deaths in the screened group and
1,230 in the unscreened group. Those who were not screened were no
more likely to die of lung cancer than those who underwent the
annual X-rays, according to the study in the Nov. 2 issue of the
Journal of the American Medical Association. The research was published early online and is scheduled to be presented Wednesday at the American College of Chest Physicians annual meeting, in Honolulu.
Lung cancer is the leading cause of cancer death in the United
States and worldwide, according to background information in the
Starting in the 1950s and through the 1970s -- a time when there
were both lots of American smokers and a growing understanding
about the dangers of smoking -- there was great interest in using
chest X-rays to screen for lung cancer, Berg explained.
Studies published in the 1980s showed chest X-rays weren't all
that effective, but those studies had small numbers of participants
and other flaws that left lingering questions that have been
answered in a more definitive way in this new study, Berg said.
Other experts agreed. "The study shows that lung cancer
screening with chest X-ray isn't very effective, and certainly not
as effective as CT scans," said Robert Smith, director of cancer
screening at the American Cancer Society. "This paper indicates
that the long tradition of using a chest X-ray to screen for lung
cancer is over."
Another study, published recently in the
New England Journal of Medicine, found that using a newer technology cut the death rate by 20 percent compared to X-rays.
Helical CT, also called "spiral" CT scan, gives a more precise
look at lung tissue. While an X-ray is a single image, portions of
which can be blocked by the ribs, a spiral CT scan takes pictures
of multiple layers of the lungs to create a three-dimensional
image. Think of it like slicing a loaf of bread, with each image
about 2.5 millimeters to 3 millimeters thick, Berg explained.
"Lung cancer screening with low-dose helical CT is the only technology that has ever been shown to lower lung cancer mortality," she said.
The downsides of CT scans are that they're more expensive, and
they have many more false positives because they're so sensitive,
While lung cancer caught early is more treatable than lung
cancer caught later, one challenge with the disease is that many
lung cancers are aggressive and difficult to treat, Berg noted.
"It's only recently that the drug companies and researchers are
beginning to find some drugs that work," she said.
U.S. National Cancer Institute has more on lung