The hidden racial bias in U.S. lung cancer screening policy

About five years ago, Vanderbilt University epidemiologist Melinda Aldrich discovered something about the U.S. cancer care system that has eaten at her ever since.

Aldrich had been studying the public health benefits of preventive lung cancer screening, widely seen as a critical first line of defense against a disease that kills more than 120,000 Americans a year — more than the combined total for breast, colon, and prostate cancers. Lung cancer is extraordinarily difficult to treat in its advanced stages, and the earlier it is detected, the better a person’s odds for survival, many experts say.

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But hospitals and insurers impose strict criteria for deciding who can receive preventive lung cancer screening, and when. At the time of Aldrich’s discovery, a person had to be between 55 and 80 years old and have smoked the equivalent of 30 pack-years — a pack a day for 30 years, say, or two packs a day for 15 — to be screened with the standard method for early detection, called low-dose spiral computed tomography. Aldrich’s analysis of more than 84,000 adult smokers revealed that under those criteria, Black patients at relatively high risk of lung cancer were being disproportionately excluded from the screening eligibility pool. More than two-thirds of Black smokers who were diagnosed with lung cancer did not meet the age and smoking history criteria at the time of their diagnosis.

“These people are getting diagnosed with lung cancer, and yet they can't even get in the door to be screened,” Aldrich later recalled.

Aldrich knew that Black Americans tended to develop lung cancer at higher rates and at younger ages than their White counterparts, despite on average smoking fewer cigarettes. And by her calculations, high-risk Black smokers were being excluded from screening at more than one and a half times the rate of White smokers.

As Aldrich saw it, the screening inequity had the potential to worsen the already staggering toll that lung cancer exacts in Black communities. According to the American Lung Association, the disease claimed the lives of more than 14,000 Black Americans in 2021, the most recent year for which there was data. Black lung cancer patients were 15 percent less likely than White patients to be diagnosed early, and had the lowest five-year survival rate of any racial group.

Based on their findings, Aldrich and her collaborators recommended lowering the age threshold to 50 and the smoking history requirement to 20 pack-years for Black smokers, to make rates of screening eligibility more equitable. Putting race at the center of cancer screening was in some ways a radical proposal, and Aldrich was prepared for pushback from her peers. But at the 2018 World Conference on Lung Cancer, where she first presented the findings, the response from the audience was very positive. Aldrich and her colleagues realized the work was going to be taken seriously.

“These people are getting diagnosed with lung cancer, and yet they can’t even get in the door to be screened.” 

Two years after the Vanderbilt study was published, the nation’s standard bearer for preventive health policy — an independent panel of experts known as the U.S. Preventive Services Task Force — revised its lung cancer screening guidelines, citing their work as a factor alongside other studies, including a large study called the Nelson trial. But rather than lower the age and pack-year requirements specifically for Black smokers, as Aldrich and her colleagues had advised, the task force loosened those criteria for all smokers, regardless of race. The new guidelines caught a larger share of Black smokers but also larger shares of White smokers and smokers of other backgrounds. As a result, it narrowed, but did not close, the racial screening gap that Aldrich and company had identified.

The task force’s decision has thrust it into the center of a simmering debate about the best way to address the factors underlying racial health disparities in lung cancer and other diseases. And it has led some experts to call for a more complete overhaul of screening policy that accounts not just for race but for genetics, environment, occupation, and other risk factors in screening decisions.

“Lung cancer [screening] is not going to be a one size fits all solution,” said Aldrich, who advocates for more personalized approaches to assessing risk. That those approaches have yet to gain traction in health policy circles, however, underscores a seemingly inescapable truth of the American health care system: With public health interventions like preventative screening, it’s nearly impossible to disentangle scientific findings from the politics and social forces that drive them.

Aldrich’s interest in racial disparities in lung cancer goes back two decades, to her days as a Ph.D. student at the University of California, Berkeley. There, she studied the genetic factors that influence lung cancer risk, and how those factors vary between Black American and Hispanic populations. When she arrived at Vanderbilt in 2010, she began deepening her understanding of the fraught topic, probing genetics, social determinants of health, and environmental risk factors.

For the better part of Aldrich’s career, there were no official national standards for screening asymptomatic patients for lung cancer — not even for heavy smokers, who are known to be at elevated risk. In part, that was because the most common tool for examining a patient’s lungs, the chest X-ray, wasn’t very good at identifying small tumors.

In 2011, however, a study known as the National Lung Screening Trial, which followed more than 53,000 people aged 55 to 74 with a history of heavy smoking, showed that low-dose spiral computed tomography, or low-dose CT, could identify early-stage tumors while they were still treatable. Study participants screened with low-dose CT had a 20 percent lower risk of lung cancer death than those screened with standard chest X-rays.

Two years later, citing that study, the U.S. Preventive Services Task Force issued its first-ever lung cancer screening guidelines: Anyone 55 or older with at least a 30 pack-year smoking history should be screened annually with low-dose CT. The recommendation, like all of the task force’s guidelines, was the product of a complex calculus that weighed the benefits of early detection against potential harms like overdiagnosis, unnecessary tests, and invasive follow-up procedures. And coming from the U.S. Preventive Services Task Force, perhaps the most authoritative voice in preventive care and evidence-based medicine, the recommendation carried substantial weight.

The task force’s 16 volunteer members, appointed by the secretary of the U.S. Department of Health and Human Services, draw on peer-reviewed evidence, as well as expert and public opinions to arrive at health care policy recommendations. When the task force sets screening guidelines, leading medical associations, insurance companies, and primary care physicians often adopt those guidelines as their own. After the task force released its lung cancer screening criteria, professional organizations such as the American Academy of Family Physicians and the American College of Chest Physicians soon issued guidelines that were essentially identical.

But there were reasons, even then, to believe that lung cancer screening guidelines based strictly on age and smoking history might disproportionately exclude Black patients from receiving potentially life-saving care. It would not take long for that policy pitfall to come to light.

It is well documented that Black smokers tend to develop lung cancer younger and more often than White smokers, despite generally smoking less: A 2006 study published in the New England Journal of Medicine found that Black smokers with a habit of up to 20 cigarettes a day were around twice as likely as White smokers to develop lung cancer; a 2015 analysis found that Black Americans were diagnosed at younger ages for nearly every cancer type, including lung, prostate, breast, and brain cancer; and an analysis of data from the National Lung Screening Trial showed that African Americans were twice as likely as White Americans to die of lung cancer, and were generally younger at the time of diagnosis.

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Although the reasons for these disparities are unclear, the 2006 New England Journal of Medicine study suggested that they can’t be explained by racial differences in socioeconomic status alone. Whatever the cause of the lung cancer disparity, Black smokers’ heightened risks likely weren’t reflected in the U.S. Preventive Services Task Force’s 2013 screening recommendations. That’s because Black patients were vastly underrepresented in the National Lung Screening Trial, the study that formed the basis of the guidelines. Only 4 percent of the trial’s participants were Black, though Black people made up roughly 14 percent of the U.S. population around the time the study was conducted.

If lung cancer screening guidelines were failing Black smokers, it may have been because the clinical trial system had failed them first.

With public health interventions like preventative screening, it’s nearly impossible to disentangle scientific findings from the politics and social forces that drive them.

Experts say this is a problem that extends beyond lung cancer. Breast cancer mortality rates, in particular, are high among Black women, who are twice as likely as White women to die of the disease before age 50. Yet for a decade, the task force recommended that women at average risk should start mammograms, the main screening tool for breast cancer, at 50, regardless of race, based largely on findings from clinical trials that lacked proportionate representation of Black women. (The task force recently updated its guidelines to recommend screening starting at 40 for women of all racial and ethnic backgrounds.) Similarly, Black men die of prostate cancer at twice the rate of White men, yet until recently, the task force advised against prostate cancer screening altogether.

Overall, White people account for 60 percent of the U.S. population but more than 70 percent of clinical trial participants, according to a study published in the journal Therapeutic Innovation & Regulatory Science. This lopsidedness has dire consequences for public health, said Laurie Fenton Ambrose, president and CEO of the patient advocacy group GO2 for Lung Cancer. “We evolve clinical trials in a way that never captures real world implication.”

The reasons for Black Americans’ underrepresentation in clinical trials are myriad and complicated. Experts point out that socioeconomic factors can render the basic logistics of trial participation — such as securing transportation and free time — difficult if not impossible for some people to manage. And Fenton Ambrose notes that around 80 percent of the general population is treated for diseases like cancer in hospitals in their local communities, not the major academic centers where most clinical trials for cancer are conducted. Those local facilities may not have the resources to offer clinical trial participation to patients, she says, and those patients might not even be able to access them if they knew they existed.

The racial imbalances in clinical trials may be partially attributable to study design. Many trials exclude patients with high body-mass indices or chronic illnesses like high blood pressure, kidney disease, and asthma — all of which are more common among Black Americans. “There’s just so many of these barriers,” Fenton Ambrose said. "I don't think there's an intention to set parameters that exclude [people of color], it’s that the end result isn’t a sufficiently represented population.” But there’s also evidence that Black patients’ poor representation in clinical trials stems partly from racism and implicit bias. A 2020 study published in the journal Cancer found that some clinical trial recruiters withheld opportunities from racial and ethnic minorities because they viewed them as “less promising.” One asserted that African Americans have less knowledge than patients of other backgrounds, and required more time to understand the study instructions. Another said they felt African Americans were less likely to comply with the protocols and rules required by a trial.

“Sometimes you'll hear researchers use the excuse that those are hard-to-reach populations,” said Carol Mangione, a primary care doctor and former chair of the U.S. Preventive Services Task Force in a 2021 interview. “I think those are hardly reached.”

The gap in clinical trial participation has led to a chicken-egg problem: While there is statistical data that shows Black people get diagnosed with and tend to die at higher rates of certain cancers, there often is not sufficient clinical trial evidence to support race-specific screening recommendations.

“We have to be much more purposeful about how we design studies so that it's easy for people to participate,” Mangione said. “We need the federal government to put out requests for clinical trials where you're only allowed to compete to do that research if you can guarantee that you're going to bring in a certain percentage of people of different groups.”

Five years after Melinda Aldrich arrived at Vanderbilt, she gained a collaborator who would be instrumental in helping her unearth the racial disparities stemming from the U.S. Preventive Services Task Force’s lung cancer screening guidelines. Kim Sandler joined the Vanderbilt faculty in 2016, fresh off a residency in radiology and fellowship in cardiothoracic imaging. She and Aldrich began working together, and among their first projects was to examine the relative impacts of the 2013 screening guidelines on patients of different racial backgrounds.

That study called for a dataset that was much more representative of the Black population than the National Lung Screening Trial that had informed the 2013 guidelines. Aldrich and Sandler decided to use the Southern Community Cohort Study, funded by the National Cancer Institute, which follows approximately 85,000 people — mostly patients at community health centers throughout the southeast — recruited between 2002 and 2009. Of the roughly 48,000 participants in the study who reported a history of smoking, more than 32,000 were Black.

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Using statistical models, Aldrich and Sandler analyzed the data to see whether those patients were being screened at appropriate rates. The results were jaw-dropping. Their models suggested that only 17 percent of Black smokers met the task force’s age criteria and 30-pack-year smoking history requirement, compared with 31 percent of White smokers. Worse, during the 12-year period that they followed the cohort for the study, just 32 percent of Black smokers who were diagnosed with lung cancer met the screening eligibility at the time of their diagnosis, compared with 56 percent of White smokers.

The data was compelling, but the remedy was hardly clear cut. “I actually remember having that discussion in the library of the Oxford House," Sandler recalls. "There was a group of us sitting around a table with all the data from tens of thousands of patients, but it was like, ‘how do we package this?’” she said. “It was that balance between what's best for the patients, what’s best for the population moving forward in the screening space, and what is most easily implementable.’”

Ultimately, the researchers recommended lowering the smoking history criterion for African Americans to 20 pack-years, and the age requirement to 50 — steps their modeling indicated would result in more equitable screening outcomes.

Aldrich and Sandler are not the only researchers to have proposed a race-conscious approach to cancer screening. A recent study published in JAMA Network Open considered racial differences in breast cancer rates and recommended that mammography screening start at age 42 for Black women, 51 for White women, 57 for American Indian or Alaska Native and Hispanic women, and 61 for Asian or Pacific Islanders. Last October in JAMA Oncology, a team led by Stanford researchers proposed that decisions to screen for lung cancer should be made using a risk-based model that takes race and ethnicity, among other factors, into account.

But efforts to incorporate race into the cancer screening equation have faced pushback, in part on political and sociological grounds. Some critics worry that such medical prescriptions will only perpetuate the notion of race as biological instead of a social construct.

Among them is Otis Brawley, a professor of oncology and epidemiology at Johns Hopkins University and former chief medical and scientific officer for the American Cancer Society. For more than three decades, Brawley’s stated mission has been “to close racial, economic, and social disparities in cancer prevention, detection, and treatment of cancer in the United States and worldwide.” Yet, he adamantly opposes making race a part of screening guidelines.

For decades, Brawley says, medicine has attributed racial disparities in cancer outcomes to a myth that Black and White people — and the diseases that affect them — differ biologically. Quoting the Nobel Prize-winning scientist Harold Varmus, Brawley said that “if you want to divide the American population into more races than one, that’ fine, but in terms of biology, that’s like trying to slice soup.”

Brawley also believes that focusing on race obscures the true driver of cancer disparities: quality of care. He notes that most Black cancer patients don’t have access to the MD Andersons and Memorial Sloan Ketterings of the world — hospitals where he says cancer outcomes are equal regardless of race. As he sees it, the examples set by those hospitals point to a very obvious solution to health disparities: “Equal treatment yields equal outcomes.” But what looks like disparity driven by biological differences is actually just a proxy for socioeconomic issues, he says, and Black patients often don’t have access to equitable treatment.

When the U.S. Preventive Services Task Force was reassessing its previous guidelines, it commissioned a modeling study that concluded that the suggested updates would confer more health benefits to more people compared to the existing guidelines. But that study’s modeling did not consider racial or ethnic disparities in lung cancer risk. In a statement emailed to Undark, Michael Barry, current chair of the task force, wrote that while the group always looks for evidence that would facilitate “specific recommendations for different racial and ethnic populations, especially those disproportionately burdened by a given disease or condition, that data often does not exist."

Barry added that "when the Task Force considered whether it was possible to include race as a variable in the model it used for its lung cancer screening recommendation, it found that there was not sufficient underlying data. The evidence was simply not available to show how race — together with the other variables in the model — affects the way people’s health progresses over time due to both lung cancer and other medical conditions a person could develop.”

For decades, Brawley says, medicine has attributed racial disparities in cancer outcomes to a myth that Black and White people — and the diseases that affect them — differ biologically.

This does not mean it won’t be included in future models, as Barry acknowledged that research is constantly progressing and that new studies will be incorporated into future revisions of the screening guidelines. Barry added that, in terms of screening eligibility, dropping the pack-year threshold from 30 to 20 benefitted the Black high-risk population more than the corresponding non-Hispanic White population. Indeed, a 2022 study in JNCI Cancer Spectrum found that while the new recommendations did not eliminate the racial gap in screening eligibility, they narrowed it. According to that analysis, the new guidelines reduced a 16-percentage-point gap between the proportions of Black and White smokers with lung cancer who were eligible for screening at the time of their diagnosis to around 11 percentage points. (Under the new recommendations, Latino smokers, who had also been disproportionately excluded from lung cancer screening under the old guidelines, became the group most likely to be excluded from screening.)

At the same time, some experts, like the authors of a 2023 JAMA Oncology study that found a persistent screening eligibility gap under the new guidelines, argued that new recommendations didn’t make screening access equitable. “Based on racially and ethnically diverse population-based cohort data, the 2021 USPSTF guidelines for lung cancer screening still induce racial and ethnic disparities,” the study authors wrote.

In a Stanford Medicine press release, Summer Han, the study’s lead author, noted: “Our study shows that these changes to the guidelines are not sufficient to address race-based differences in lung cancer incidence and age at diagnosis.”

As some public health experts see it, stringent screening eligibility guidelines aren’t the biggest obstacle to closing lung cancer disparities. Kathy Levy, a former project manager for GO2 for Lung Cancer’s Alabama Lung Cancer Awareness, Screening, and Education project, known as ALCASE, said it matters little whether screening guidelines incorporate race because even eligible people face significant barriers to getting screened.

Levy spent three years working to get more underserved people of color screened, diagnosed, and treated for lung cancer throughout Alabama’s Black Belt, a rural region home to large African American populations, and she remembers it as a slow process to get started.. There, she says, practically any cancer diagnosis comes with a social stigma. “We're rural and a cancer diagnosis is so secret,” said Levy. “They’ve just gotten to where they would start saying the word ‘cancer.’ They would call it ‘the Big C’.”

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Some Black people also feared getting a diagnosis because they viewed lung cancer as an automatic death sentence, she said, and didn’t want to know if they had it. “We had to do a lot of education, and a lot of hand holding, just showing the love and concern to these people that were out there in the neighborhood. You might have to talk with them six or seven times.”

Nationally, just 5.8 percent of people who are eligible for lung cancer screening are actually screened; in some states, the number is only around 1 percent. According to the 2022 Lung Health Barometer from the American Lung Association, nearly 70 percent of people don’t even know that lung cancer screening exists. Black adults who are eligible for lung cancer screening are even less likely than people from other backgrounds to undergo the procedure, Levy said, due to distrust of the health care system and lack of access to care.

According to Levy, the challenges don’t stop with the patients; many health care providers remain uninformed about proper lung cancer screening. She recalls sending patients for screening only to have their doctors pronounce them clear after listening to their lungs and ordering a chest X-ray, procedures that are known to be ill-equipped to detect early tumors. She later created a “Dear Doctor” letter that her patients could give to their physicians — a missive that explained the screening process and included a list of facilities that offered low-dose CT scans.

The persistent frustrations notwithstanding, Levy believes her work has made a difference, particularly in her home county of Choctaw, where she is known as “the Cancer Lady” who pesters everybody about getting regular check-ups and screenings. Now, they call her asking if it’s time to get screened again, she said with a soft chuckle.

Although Levy is doubtful that any screening policy change would fix the lung cancer woes that plague the Black Belt, she takes issue with the use of age restrictions on screening, a barrier that could disproportionately affect Black smokers. “I wish it was that we didn't have to worry about age on the screening because we have people that are actually younger now, [that are] getting cancer at such an early age,” she said. “Why do we have to put stipulations about an age on screening for our health?”

The debate over race-conscious screening guidelines is taking place against a backdrop of rapid changes in the treatment and scientific understanding of lung cancer.

Experts acknowledge that cancer screening is imperfect , although many emphasize that they think it is worth any associated risks. For instance, early detection can skew screening statistics for topics such as five-year survival rate, even if it does nothing to extend a person’s life. One educational resource by the National Cancer Institute showed how a common metric, the five-year survival rate, can sometimes mislead: If a group of patients are diagnosed with cancer at 67 and then die of the disease at 70, they would effectively have a zero percent five-year survival rate. But if they are diagnosed early, at 60, and also die at 70, the group would have a 100 percent five-year survival rate — even though the early detection may not have helped them live any longer. The National Cancer Institute references this so-called “lead-time bias” as one of the causes of confusion and misunderstanding about screening efficacy.

“Doctors frequently talk about survival rates,” says Brawley, the Johns Hopkins epidemiologist. He says he frequently tells his graduate students that if doctors are just talking about survival without talking about it in a randomized trial, "you have someone who doesn't know what the hell they're talking about.”

Brawley points out that the interventions and follow-up tests that come after a positive screening result can themselves be risky. He calculated that the follow-up procedures for the group in the National Lung Screening Trial that got a low-dose CT scan killed one person for every 5.4 people the new screening method saved. Modeling work used by the U.S. Preventive Services Task Force in determining the new guidelines predicted less dire — but nonetheless significant — screening harms, including roughly one radiation-related death occurring due to annual screening for every 13 cancer deaths averted. The same model predicted around two false positives per person over a lifetime of screening, with some of those false positives resulting in follow-up biopsies. One study found that the mortality rate for patients who elect to have a surgical lung biopsy in hospitals is just under 2 percent, and almost 10 times higher than that for people who have it as a nonelective procedure.

These sobering statistics reinforce the need to target screening at people at highest risk in order to reduce the number of false positives and risky follow-up procedures. The stigma of smoking leads many people to lie about or legitimately underestimate the extent of their smoking history, making it too crude an indicator of risk for some. Jennifer King, GO2’s former chief scientific officer and now the chief science officer at the International Association for the Study of Lung Cancer, would like to see clinical trials and screening recommendations consider additional risk factors, including genetic mutations known to be associated with heightened cancer risk, family history, and prior history of cancer. As she puts it, “Smoking history is not going to find everybody.”

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When King says “everybody,” she may be referring to people like Diane Juitt, a 59-year-old resident of Columbia, South Carolina who is among the 10 to 20 percent of American lung cancer patients who have never smoked or smoked fewer than 100 cigarettes in their lifetime. When Juitt developed an unshakeable, bone-rattling cough in the summer of 2021, she never imagined she might have lung cancer. She attributed her symptoms to the residual effects of a Covid-19 infection she’d battled earlier in the year. “It kept getting worse,” she recalls. The first time she saw a doctor, he gave her something for the cough and “it went away, but then it just came back.”

Juitt, who was preparing for retirement from her job with the Army National Guard, decided to undergo a complete physical, which included a chest X-ray that revealed a spot on her lung. A follow-up low-dose CT scan led to a biopsy. By the time doctors at the Hollings Cancer Center at the Medical University of South Carolina in Charleston performed surgery, her cancer was at stage 3: The tumor had not invaded adjacent organs, but cancerous cells had spread to nearby lymph nodes in the chest. Doctors removed part of her lung and about 30 lymph nodes.

Juitt is Black, but genetics may have been a more critical risk factor for her lung cancer. Subsequent tests revealed that she had a genetic mutation that increased her risk for the disease. Her two daughters were screened for the same mutation based on her experience.

The U.S. Preventive Services Task Force does not recommend lung cancer screening for people who have never smoked. It says that current evidence does not support adding other risk factors than smoking to the screening guidelines. But cases like Juitt’s exert pressure for the screening guidelines to evolve.

The American Cancer Society recently updated its guidelines to eliminate the number of years since quitting smoking as an eligibility factor. Many researchers favor expanding the eligibility pool for lung cancer screening and considering a broader array of risk factors in screening decisions.

Aldrich would like to see the guidelines take into account not only smoking history and race, but also other demographic factors and genetic sequencing. “Race is complicated,” she said. It’s difficult to disentangle it from social factors, diets, culture, genetic variants across populations.

Fenton Ambrose, of GO2 for Lung Cancer, suggested that certain classes of workers, such as first responders and military servicemembers, should also be prioritized for screening. Lung cancer incidence and mortality rates are much higher for military personnel than the general population, due to occupational exposures to an assortment of toxins.

Many researchers favor expanding the eligibility pool for lung cancer screening and considering a broader array of risk factors in screening decisions.

While Barry, the U.S. Preventive Services Task Force chair, agrees that it's a good thing to look for additional risk factors and focus screening on people who would most benefit, he also warns that more complicated implementation procedures might push people away. "Our recommendation currently using just age and pack years is pretty straightforward," he said. In trying to fine tune those criteria, he added, "we want to be careful not to create an implementation barrier when we already know even with the simple criteria, that lung cancer screening is underutilized."

Meanwhile, Aldrich’s collaborator, Sandler, believes that many screening eligibility guidelines are likely to change in the not-too-distant future. She points to ongoing studies that are evaluating the benefits of screening other high-risk populations. And she’s hopeful that new diagnostic tests will emerge to augment low-dose CT in the screening process. Researchers in the U.S. and Taiwan, for example, have developed a new AI tool that can detect predict future lung cancer risk within the next six years based off of a single low-dose CT scan; other tests can identify minute genetic markers circulating in the blood that signal residual or recurrent cancer.

In terms of the future evolution of the task force screening guidelines, “my hope is that they will continue to address disparities in race and gender,” Sandler said, “and that we also continue to look at access.”

Melba Newsome is a freelance science, health, and environmental journalist in Charlotte, North Carolina.

This reporting was supported in part by a grant from the National Institute for Health Care Management Foundation.

This article was originally published on Undark. Read the original article.