WASHINGTONWhen used to diagnose early lung cancer, low-dose
spiral CT scanning has a high specificityas well as high
sensitivityand it is cost-effective, according to
as-yet-unpublished data from the New York City-based Early Lung
Cancer Action Program (ELCAP). Moreover, the technique can diagnose
emphysema at an earlier stage than existing tests, which has helped
smokers in the study to stop.
We think that screening saves lives of former smokers and
current smokers, said Claudia I. Henschke, MD, PhD, professor
of radiology, Cornell Universitys Weill Medical College, and
director of chest imaging, New York Presbyterian Hospital. It
is cost-effective, and it encourages smoking cessation and should be
combined with smoking cessation. That combination will be even more cost-effective.
ELCAP enrolled 1,000 men and women age 60 or older who had smoked at
least a pack of cigarettes a day for 10 years or two packs a day for
5 years. Dr. Henschke and her colleagues reported findings from the
first year of the study in 1999.
Their report set off what some have called call the spiral CT
rush, as many radiology centers rushed to offer the
test to smokers and former smokers as a way of diagnosing early lung cancer.
Dr. Henschke described some data from the studys second year at
a conference on reducing lung cancer mortality sponsored by the
Cancer Research Foundation of America and the Roy Castle
International Center for Lung Cancer Research, Liverpool, England.
ELCAP team initially reported that 233 of the people scanned had
suspicious lesions, defined as one to six noncalcified nodules (see
Figures 1-3). Of these 233 patients, 27 were diagnosed with lung
cancer, and of those who were staged, 85% were found to have stage I
Thats a marked reversal to the 8% that is found in the
United States currently, Dr. Henschke said. The study
clearly demonstrated that spiral CT can pick up lung tumors when they
are small and treatment offers the greatest chance of survival.
She and her colleagues are now beginning a much larger New York City
and state ELCAP study that will enroll 10,000 high-risk subjects at
up to 12 centers. In addition, more than 10,000 subjects at 10
centers will be enrolled in the International Collaboration to Screen
for Lung Cancer. The international study will have somewhat more
flexible entry criteria than ELCAP in terms of age, she noted.
ELCAP participants were rescanned 1 year after their initial spiral CT screening. The key thing
in the screening program is what happens on annual repeat, not so
much on baseline, Dr. Henschke said. On annual repeat,
this really becomes a terrific test.
Team members found that 1.5% of those rescreened had new noncalcified
nodules, many of them being small focal infections, which were
treated with antibiotics and resolved. As expected, a larger
percentage of nodules found on repeat examination41%were
cancerous, and 83% of those were stage I.
So now it becomes a highly specific test, about 98% specific,
as well as being highly sensitive, Dr. Henschke said.
Evidence supports lung cancer screening as being cost-effective, she
added, citing a study reported in the May issue of the Canadian
Medical Journal. That study showed annual screening costs with
low-dose spiral CT of between $5,000 and $10,000 per life-year saved.
Weve shown that baseline screening costs only about
$1,000 per life-year saved because were finding many more
cancers at baseline than on annual repeat, she said.
Benefits of Resection
The ELCAP team addressed the issue of whether early tumors picked up
by spiral CT scanning are actually deadly. To do that, they examined
data from the National Cancer Institutes Surveillance,
Epidemiology, and End Results (SEER) program on the survival rates of
stage I lung cancer patients who had undergone full resection,
partial resection, or no resection, a category that included people
who underwent radiotherapy or chemotherapy without surgery.
Theres a dramatic difference between no resection and
full resection, Dr. Henschke said. These early lung
cancers are ones that can kill or that do kill.
Earlier NCI-sponsored studies at Memorial Sloan-Kettering, Johns
Hopkins University, and the Mayo Clinic showed that resected stage I
lung cancer patients had a survival rate better than 70%, while those
who refused or could not undergo surgery had less than 10% survival.
Studies in Japan have also found a survival rate of 10% among stage I
lung cancer patients who did not have resection.
To answer those who might complain that patients who were not
resected might have been incorrectly staged, the researchers looked
at SEER survival data for lung cancer patients with other stages of
the disease, including those with node involvement. They found
similar gaps in survival between resected and unresected patients.
This really should show everybody convincingly that theres
a dramatic difference between resection and nonresec-tion, and even
those small cancers kill, Dr. Henschke said.
Bringing Down Lung Cancer Mortality Rates
A projected 164,100 new lung cancers will be diagnosed in the United
Although it is too early in ELCAP to determine cure rates, the team
has done some statistical projections for the relationship between
tumor size and survival. Using SEER data, the researchers plotted the
survival rates of lung cancer patients out 10 years.
We show that theres a statistically significant
difference between the survival of individuals who started out with
tumors less than 15 mm, 16 mm to 25 mm, and so on, Dr. Henschke
said. And we can show by logistic regression that theres
a decrease in the cure rate for every millimeter increase in tumor
In addition, the team looked at SEER data on a subset of lung tumors
that were 15 mm or smaller, in which the large majority of cancers
were between 10 and 15 mm. Even for these tiny lung cancers,
theres a dramatic difference between full resection and
nonresection, Dr. Henschke said.
Again using SEER data, ELCAP researchers have examined the
relationship between tumor size and metastasis. We see an
exponential increase of progression of disease or just the
metastasisincurable diseaseby size, Dr. Henschke
said. It really points out how much we should focus on this
interval, looking for lung cancers below 1 cm.
The ELCAP screenings returned an unanticipated benefitevidence
of very early emphysema on CT screening helps patients stop smoking.
We would go through the CT scans of the individuals, and they
were all very shocked about their emphysema, Dr. Henschke said.
So we would talk about it, and then they would call up several
months later and say, You know, that was really very helpful.
Every time I lit a cigarette, I had the image of my CT scan in front
of me, and it helped me to quit.
After hearing a number of such anecdotes, the team commissioned a
survey of 300 of the 1,000 ELCAP participants by researchers outside
We found that among those who were still smoking at the time of
enrollment, 23% quit, another 23% decreased their smoking, and the
rest stayed the same. Almost all of them attributed the change to
enrollment in the ELCAP program, Dr. Henschke said.
This finding has led the team to suggest combining annual screening
with efforts to get smokers to stop. You can really personalize
smoking with this information, and encourage smokers to quit,
Dr. Henschke said.