Dartmouth scientists said that lung cancer screening in the
National Lung Screening Trial (NLST) found a commonly accepted standard for
This relatively new screening test uses annual low-dose CT
scans to spot lung tumors early in individuals facing the highest risks of lung
cancer due to age and smoking history.
The research was funded by the National Cancer Institute, a
health agency under the US Department of Health and Human Services.
"The takeaway from this study is that there is potential for
lung cancer screening to be done in a cost-effective manner, particularly for
adults 65-75 years of age," said William C. Black, MD, chair of the Lung Cancer
Screening Group at Dartmouth-Hitchcock Medical Center and professor of
Radiology, of Community & Family Medicine, and of The Dartmouth Institute
for Health Policy and Clinical Practice, Geisel School of Medicine at
Dartmouth. Black is the principal author of the paper and a leading national
researcher of lung cancer screening.
The Dartmouth study found that screening costs $81,000 for
each quality-adjusted year of life it produces. The statistic, known as Cost
per Quality-Adjusted-Life-Years (QALYs), considers the overall costs of a
medical intervention to a selected population to produce one year of perfect
health. For policy makers, this ratio establishes relative worth from an
economic perspective. A proposed benchmark for cost-effectiveness is
"I think the vast majority of health economists would
consider the threshold to be close to $100,000 per QALY," said Black.
When the researchers looked at specific subgroups of study
participants, they found lung cancer screening was most cost-effective for current
smokers, women, and for people in their sixties.
"Although precision with subsets is not as good as overall,
people at higher risk seemed to benefit more from screening, so, for example,
current smokers benefited much more than people who had quit," said Black.
Lung cancer screening is not yet standard medical practice.
Over the last two years, multiple professional associations have issued
statements that recommend physicians offer annual lung cancer screening to
individuals 55-80 years old who have more than a 30-pack years history of
As a result of a positive recommendation (Grade B) handed down by the U.S.
Preventive Services Task Force in December, 2013, commercial insurers will be
required to cover the test as a preventive service with no co-pays or
deductibles. The Centers for Medicare and Medicaid Services (CMS), however, has
yet to issue its final decision on reimbursement. A preliminary panel
recommended against coverage by CMS this past spring. The final report from CMS
is expected in the next week.
In this study Dartmouth researchers evaluated more than
53,000 participants in the seven-year NLST. This randomized control study was
the one credited for proving that low-dose CT screening for lung cancer can
save lives. For each 1,000 people screened there were about three fewer deaths
from lung cancer. NLST followed strict protocols and the results of this study
do not necessarily apply to lung cancer screening programs implemented
Lung cancer screening is not without risks. In the NLST,
roughly one-third of those screened had a "false alarm" requiring further
testing, usually a repeat of the CT scan, to rule out lung cancer. Some
additional tests are invasive and come with a small risk of serious
Since the NLST was conducted, the American College of
Radiology (ACR) narrowed its definitions of a "positive" lung cancer screening
test. This stricter guideline should substantively decrease the number of false
alarms resulting from the test.
"The new ACR LungRADs reporting system should reduce the
false positive rate by about 50 percent," said Black, "and reduce the
cost-effectiveness ratio by several thousand dollars per QALY gained."
The study was conducted in collaboration with investigators
at the Brown School of Public Health, Pardee RAND Graduate School, University
of California at Los Angeles, University of Minnesota School of Public Health,
and the University of South Carolina at Charlestown. Co-authors included Ilana
F. Gareen, Samir S. Soneji, JoRean D. Sicks, Emmett B. Keeler, Denise R.
Aberle, Arash Naeim, Timothy R. Church, Gerard A. Silvestri, Jeremy Gorelick,
and Constantine Gatsonis.