Physicians Refining Lung Cancer Screening Program
By Joe Munch
|A lung tumor in the left upper lobe is visible in a low-dose computed tomography scan (left) but not in a posteroanterior chest radiograph (right) of the same patient.
cancer screening with low-dose computed tomography (CT) has been shown
to reduce the rate of lung cancer–specific mortality in people at high
risk for the disease.
Three years after the National Lung Screening Trial (NLST) showed this
definitively, physicians and researchers at The University of Texas MD
Anderson Cancer Center have implemented the NLST’s findings in a
screening program and are developing new methods of identifying
patients who would most likely benefit from screening.
“We’re working to better understand who we should screen and what we
should do with any abnormal results we find,” said Therese Bevers,
M.D., a professor in the Department of Clinical Cancer Prevention.
MD Anderson’s CT screening program
Established shortly before the publication of the NLST’s primary
findings in 2011, the CT screening program at MD Anderson’s Lung Cancer
Screening Clinic follows the criteria set forth by that landmark study.
Annual screening with low-dose, thin-slice multidetector CT of the
lungs is recommended for asymptomatic individuals at a high risk of
lung cancer—those 55–74 years old who have a smoking history of at
least 30 pack-years and are current smokers or former smokers who quit
within the past 15 years. Screening is not recommended for individuals
at low risk—those with no current or former history of smoking.
|“We’ve already shown a 20% reduction in mortality using the NLST indications for CT screening. Now, we’re simply asking what contribution a blood-based test would add to lung cancer screening.”
|– Dr. Samir Hanash
For individuals who have a moderate risk of lung cancer (i.e., those at
neither a high nor a low risk of the disease), the recommendation to
undergo screening is ultimately left to the discretion of the patient’s
physician. People in the moderate-risk category do not meet the
screening criteria established by the NLST but have a combination of
variables that suggest that the benefits of screening could outweigh
“A moderate-risk individual might be a person who is only 50 years old
but has a 40 pack-year smoking history,” Dr. Bevers said, “or maybe a
patient who quit smoking 20 years ago but has a 50 pack-year smoking
history. Those patients would have a moderate risk because they don’t
meet the exact high-risk criteria as defined by the NLST but still have
significant risk of lung cancer due to their enormous smoking
People who have a history of cancer other than lung cancer related to
tobacco use are also included in the moderate-risk category.
Acknowledging the mounting evidence that individuals who have chronic
obstructive pulmonary disease (COPD) as a result of their smoking are
at higher risk of lung cancer, Dr. Bevers also suggested that such
people be included in the moderate-risk category.
Although the NLST showed a benefit through 3 years of screening with
CT, MD Anderson recommends that individuals at high risk of lung cancer
undergo annual screening with low-dose CT for as long they remain in
good health and able to undergo additional interventions if lung cancer
is discovered. In addition, through its Tobacco Treatment Program, MD
Anderson offers tobacco cessation services to all the institution’s
patients who currently smoke or have quit smoking within the past year.
Patients must have an order from a physician to be able to undergo lung
cancer screening at MD Anderson, and the screening results are sent to
the physician. However, Dr. Bevers said that she or other physicians in
the Cancer Prevention Center can order screening for patients who do
not have a primary care physician or for those whose primary care
physician is not comfortable managing the outcomes of CT screening.
Cost and coverage
Currently, few insurance plans cover lung cancer screening, and many
people have to pay for the service out of pocket. At MD Anderson,
screening costs $250, which includes the charge for performing CT as
well as a radiologist’s interpretation of the study. For many
individuals, this cost is prohibitive.
This may soon change, however. In late December, the U.S. Preventive
Services Task Force issued a statement recommending annual lung cancer
screening with low-dose CT for adults who meet the NLST criteria. Per
the 2010 Affordable Care Act, private insurance companies participating
in the Health Insurance Marketplace established by the legislation must
cover services the Task Force recommends with no cost to patients.
Dr. Bevers expects that the added coverage will result in an influx of
patients to the screening program. “We’ve seen it with all other
screenings: once they’re covered by insurance, patients are more likely
to participate,” she said.
She also believes that, although they have no legal obligation to do
so, Medicare, Medicaid, and private insurance companies not
participating in the exchanges will eventually cover the screening if
data show the procedure to be cost-effective.
Improvements to screening
Lung cancer screening is not without risk. Although the amount of
radiation exposure from low-dose CT (1.5 mSv) is considerably less than
that from diagnostic CT (7 mSv) or even that of yearly background
levels (3–5 mSv), increasing evidence suggests that cumulative
radiation effects may have harms associated with them, including an
increased risk of cancer.
|“We’re working to better understand who we should screen and what we should do with any abnormal results we find.”
|– Dr. Therese Bevers
And the screening is not perfect: the NLST found a high false-positive
rate, largely owing to the detection of benign lesions. In many
patients whose CT findings were positive, a watch-and-wait approach
with follow-up CT that revealed no changes confirmed the absence of
lung cancer. Other patients required interventions.
“At worst, you end up having to perform a needle biopsy to determine whether cancer is present,” Dr. Bevers said.
To help address these issues, researchers at MD Anderson are developing
a blood test to guide decision-making in the face of abnormal findings
on lung cancer screening CT. The blood test will include a panel of
biomarkers found to be associated with increased lung cancer risk. A
clinical trial of the blood test will soon be open to patients who
undergo lung cancer screening at MD Anderson.
“If you have a blood test that could discriminate what is cancer from
what is not cancer, you could save a lot of unnecessary procedures and
encourage people to undergo CT screening,” said Samir Hanash, M.D.,
Ph.D., a professor in the Department of Clinical Cancer Prevention,
noting that such a blood test could allay people’s concerns about
possibly having to undergo unnecessary procedures because of
“We’ve already shown a 20% reduction in mortality using the NLST
indications for CT screening,” Dr. Hanash said. “Now, we’re simply
asking what contribution a blood-based test would add to lung cancer
Dr. Hanash said there are plans to expand the trial to include other
institutions nationally and worldwide. As the test is evaluated and
refined, its role in lung cancer screening may change.
“If a test turns out to be good at detecting cancer, then one can
imagine down the road that perhaps it would be more logical to first
get a blood test, and if the blood test is positive, then that would be
an indication to get a CT study,” Dr. Hanash said. “But we’re not there
yet. We have to crawl before we walk and walk before we run. What is
very compelling to do now is to figure out a way we can improve on CT
contact Dr. Therese Bevers at 713-745-8048 or Dr. Samir Hanash at
713-745-5242. View MD Anderson’s lung cancer screening algorithm (PDF).
To refer a patient to MD Anderson’s Lung Cancer Screening Clinic, call
877-632-6789 or visit www.mdanderson.org.
articles in OncoLog, March 2014 issue:
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