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A small fraction of those who were eligible under previous U.S. Preventive Services Task Force recommendations were screened with low-dose CT scans. New recommendations will make an additional 6.4 million Americans eligible, but a number of barriers to screening remain.
When the U.S. Preventive Services Task Force (USPSTF) recommended screening current and former smokers for lung cancer with low-dose CT scans in 2013, it held the promise of ushering in a new era of lung cancer diagnosis and treatment.
Screening for other cancers has kicked up some controversies about overdiagnosis and the quality of evidence for a mortality benefit, and lung cancer screening is not entirely free of those. But USPSTF recommendations were based on a large, randomized trial that showed a 20% improvement in lung cancer mortality. Screening would mean catching many more cancers at an earlier, more treatable stage, and lung cancer remains, by far, the leading cause of cancer-related death in the U.S. About 8 million Americans were eligible for lung cancer screening, according to the recommendations that the USPSTF issued at the time.
But only a small percentage of Americans who met the criteria set by the USPSTF guidelines have gotten screened. Estimates of the proportion vary, but they range from 6% to 18%. The list of reasons is long: fear of radiation exposure, stigmatization of smokers, lack of insurance coverage, to name just a few. Aside from willingness, the eligibility criteria set by the USPSTF may have had some discriminatory effects. According to one study, the criteria would have excluded 67.8% of Black smokers who received a diagnosis of lung cancer compared with 43.5% of White smokers.
In March 2021, the USPSTF updated its lung cancer recommendations in two important ways. It lowered the age at which screening should be performed, from 55 to 50. It also lowered the number of “pack-years” from 30 to 20. Pack-years are a measure of how heavily someone smoked and for how long. For example, someone who smoked two packs of cigarettes a day for two years would have a four pack-year smoking history. By some estimates, the new guidelines will mean an additional 6.4 million Americans, or a total of about 14.5 million, will be eligible for lung cancer screening, an 80% increase from the number eligible under the 2013 recommendations.
A study published in JAMA at the time the new guidelines came out found that the percentage of Black smokers who would be eligible for screening would increase from 16.3% under the old guidelines to 28.8% under the new ones.
For proponents of lung cancer screening, the question now is how to turn expanded eligibility into more actual screening. John Bulger, D.O., chief medical officer at Geisinger Health Plan in Danville, Pennsylvania, says the health plan is implementing claims configuration and that there is no cost sharing.
“The biggest challenges that we see are getting the word out to members and their doctors,” Bulger says. “Additionally, there is a need for clinical facilities that perform the testing. Geisinger’s clinical enterprise has a streamlined process set up to identify patients, get them tested, close the loop on results, and schedule any further testing. More programs such as this are needed.”
Reducing false positives
But some wariness about lung cancer screening is understandable given its history. Chest X-rays and sputum cytology also looked promising but were abandoned when more rigorous research showed they didn’t reduce lung cancer mortality. That background is one reason the National Cancer Institute conducted a $300 million randomized trial of low-dose CT scans. In 2011, results from the National Lung Screening Trial (NLST), which enrolled a total of about 53,000 study volunteers, were a “win” for lung cancer screening. They showed a 20% lower risk of lung cancer mortality among those randomized to be screened with the low-dose CT scans compared with those who were screened with chest X-rays. Other research has found a lung cancer mortality benefit from low-dose CT scans.
Last year, results reported in The New England Journal of Medicine from the NELSON study, a large, randomized trial conducted in the Netherlands and Belgium, showed a 24% reduction in lung cancer mortality in the CT scan group compared with the control group that wasn’t screened.
Adam Saltman, M.D., chief medical officer at Eko, a cardiopulmonary digital health company, says low-dose CT scanning has revolutionized the field of lung cancer screening. “It has detected many small, early-stage cancers and facilitated curative treatment for many who would not have presented until much later in their disease,” he says.
Historically, between 60% and 70% of patients with lung cancer have stage 3 or 4 cancers, notes Mark Dylewski, M.D., chief of general thoracic surgery at Baptist Health South Florida’s Miami Cancer Institute. “That number is changing with the implementation of screening with CT scans,” he says. “We’re catching more and more patients in the earlier stages — stage 1 and stage 2 — where surgery can have an impact at curing those patients.”
As is true for many cancer screening tests, false positives are a drawback of lung cancer screening with low-dose CT scans. In the NLST study, just under 1 in 4 (23.3%) of the scans resulted in a false positive reading: The scan discovered a nodule — a small growth in the lung — that wasn’t cancer. Several years ago, the National Comprehensive Cancer Network and the American College of Radiology’s program to standardize lung cancer screening raised the size threshold for a positive nodule from 4 millimeters (mm) to 6 mm. When data from NLST were reanalyzed using 6 mm as the threshold, the false positive rate decreased to 13% and to 5% at subsequent readings. Saltman notes the progress that has been made in the follow-up tests.
“[That low-dose CT scans] have identified a lot of lung lesions that are not cancer is a bit of conundrum but the field is maturing through the use of thin-needle biopsies, PET/CT scanning, electromagnetic navigational bronchoscopy and others,”
Even if the false positive rate were zero, some people will be reluctant to get screened because of the radiation exposure. It is called low-dose CT scan screening for a reason: The radiation is about one-fifth of the radiation a person receives during a diagnostic CT scan. However, the recommendations are to get screened every year, so there is some concern with the cumulative exposure and whether that might increase cancer risk. Several years ago, Italian researchers calculated that the benefit far outweighed risk: For every 108 lung cancers detected with screening, one radiation-induced cancer might occur, they reported in an article in The BMJ. Nonetheless, it is a risk and one that might increase with the new USPSTF recommendations to start screening at a younger age.
In the U.S. and in many countries, smoking is now a behavior that is more common in disadvantaged populations: people living in poverty or with disabilities or behavioral health problems — or some combination of the three. Yet a 2018 review of 14 studies of lung cancer screening programs found that the participants tend to have a relatively high socioeconomic status. That review, which included studies of programs in other countries, also found that former smokers were more likely to be screened than current ones, a difference that may reflect, in part, the stigma attached to smoking.
In the U.S., lack of health insurance is a barrier for some. The USPSTF gave a B rating to low-dose CT scan lung cancer screening, and the ACA requires that most health plans cover preventive services with a USPSTF services with an A or B rating. But those requirements don’t necessarily apply to people covered by Medicaid. An American Lung Association report showed that screening was not covered by Medicaid fee-for-service programs in 12 states. The report is based on information collected several years ago, so some states may have since changed their coverage.
Also, managed Medicaid plans may cover the screening in states where the fee-for-service program doesn’t. Regardless, Medicaid coverage is patchy, and smoking rates are higher among people covered by Medicaid than among people covered by Medicare or commercial insurance. Medicare finalized a national coverage determination for low-dose CT scans in February 2015. But there are some hurdles in Medicare, too. For one, the program requires submission of data to a CMS registry. For another, CMS has a formal shared decision-making requirement for the low-dose CT scans that, in theory, might encourage screening but, in practice, may be an impediment.
Karen Winkfield, M.D., Ph.D., executive director of the Meharry-Vanderbilt Alliance, a partnership between Meharry Medical College and Vanderbilt University Medical Center, both in Nashville, Tennessee, notes although that although most insurance plans and Medicare cover low-dose CT scans for lung cancer screening, “the stinger is Medicaid is not requiring coverage, so it leaves a little bit of a gap for certain communities. Part of the challenge is many of the individuals on Medicaid are the same individuals who have lower socioeconomic status and tend to have higher rates of lung cancer.”
In states that have expanded Medicaid, cancer screening goes up, Winkfield notes. “But we are still struggling with what happens after you screen a patient, because lung cancer can be a very multimodal way about diagnostics if there is a finding on a scan. We need to make sure people have access to follow-up care. It cannot just be on the screening.”
In a review article published last year in the Journal of Thoracic Oncology, lead author Jacob Sands, M.D., a lung cancer specialist at Dana-Farber Cancer Institute in Boston, and his colleagues wrote that a lung cancer screening program that uses low-dose CT scans should have a program navigator, a reliable database for patients and a nodule monitoring and multidisciplinary committee. Sands and his colleagues also mention the need to work with primary care physicians, partnership with community leaders and organizations, and standardization of radiology reporting as important aspects of a screening program.
Winkfield, who works on health equity issues and differences in health and access to healthcare among racial and ethnic groups, notes that 2013 USPSTF recommendations excluded a lot of African Americans. The “smoking intensity” — the number of pack-years — tends to be lower among Black Americans than White Americans, but Black Americans develop lung cancer at a younger age. There’s some evidence that Black smokers have a higher risk of developing lung cancer than White smokers at relatively low levels of smoking. Black smokers tend to smoke menthol cigarettes more than White smokers, and some explanations of the lung cancer differences at the same level of smoking cite menthol cigarettes as the reason because of evidence that they may lead to more nicotine and carcinogen exposure per cigarette than other cigarettes.
The new USPSTF recommendations may narrow the eligibility gap between Black and White smokers but may still mean that Black (and Hispanic) smokers are underrepresented in screened populations. Some research shows that adding assessments to those recommendations to identify “high-benefit” individuals would close the gap and possibly eliminate it.
Lung cancer screening may be particularly important for Black men. Lung cancer incidence and death rates are higher among Black men than among White men; it’s the reverse for Black women and White women. The differences may be related to smoking rates. According to the American Cancer Society, in 2017, smoking prevalence was higher among Black men than among White men (19% versus 17%) but lower among Black women than among White women (12% versus 15%).
“If you look at the data related to the number of new cases related to lung cancer, Blacks had a much higher incidence a couple of years ago but the numbers have evened out more recently,” says Winkfield, “although Black men still have a higher rate of developing lung cancer than White men, and we see Black men are dying at a much higher rate of lung cancer.”
That’s why it’s so important to prioritize the African American community for screening, Winkfield says. She has also been thinking about other groups. “Part of the challenge in any screening program is awareness and getting the word out that individuals are aware of the recommended health promotion things to do,” she says. “You have to think about our underserved communities, whether that’s our Black and Brown individuals or those in rural communities or LGBT-plus communities.” Moreover, many in underserved populations are disproportionately uninsured and don’t have a primary care provider. Those providers play a crucial role in screening uptake because they advise and refer patients. Winfield says the broader use of lung cancer screening could also be an opportunity to get patients who are currently smoking into cessation programs. “Cancer is going to be the No. 1 killer in the U.S. very soon,” she says. “We have to use every opportunity to talk to individuals around risk reduction.
Keith Loria, a frequent contributor to Managed Healthcare Executive®, is a freelance writer in the Washington, D.C., area.