Achieving Equity in Lung Cancer Screening for Black Individuals Requires Innovation to Move Beyond “Equal” Guidelines

Systemic or structural racism is a system in which public or institutional practices work, intentionally or unintentionally, to perpetuate inequity by race and ethnicity. The US Preventive Services Task Force (USPSTF) recently committed to address systemic racism through its recommendations for clinical preventive services.¹ Unfortunately, the criteria that define eligibility for lung cancer screening based on age and smoking pack-years may meet the definition of systemic racism by causing disparities in screening eligibility. Identifying a solution will require understanding the underlying causes of the disparities, defining the disparity we wish to eliminate, and developing tools to eliminate this disparity.

Eligibility is only 1 aspect of the disparities in lung cancer screening, but it merits special attention because it serves as a gatekeeping step. In March 2021, the USPSTF broadened eligibility for lung cancer screening by lowering the starting age from 55 to 50 years and the minimum number of pack-years smoked from 30 to 20 pack-years for those who currently smoke or quit within 15 years.² The USPSTF believed that these changes might reduce racial disparities in screening eligibility compared with the 2013 criteria and noted that the relative increase in the number of individuals eligible would be larger for non-Hispanic Black adults (107%) than non-Hispanic white adults (78%).²

Under the 2013 USPSTF recommendation, it was estimated that self-identified White individuals would gain 48% of the life-years potentially gainable among all White current or former smokers aged 50 to 80 years. This was compared with 33% for self-identified Black individuals—an absolute disparity of 15%.³ The 2021 recommendation allows White individuals to gain 64% of potentially gainable life-years compared with 48% for Black individuals.² Therefore, while the relative improvement is indeed greater for Black individuals (45% in Black individuals vs 33% in White individuals), the absolute disparity remains 16%—essentially unchanged from the 15% disparity in the 2013 recommendation; this implies that Black individuals will continue to accrue less of their potential benefit from lung cancer screening than White individuals.

An important source of this disparity is that, for 2 people with the same age and smoking history, a Black person has a higher risk for lung cancer than a White person. This disparity is most pronounced at lower smoking intensity; for people reporting 31 or more cigarettes smoked per day, lung cancer risk is 22% higher among Black than White individuals. This excess risk increases to 37% for 21 to 30 cigarettes smoked per day, 75% for 11 to 20 cigarettes smoked per day, and 122% for less than 10 cigarettes smoked per day.⁴ In the current US population, among lung cancer deaths that will occur among people aged 55 to 80 years, 80% of deaths among White individuals occur among those who smoked 20 pack-years or more compared with 62% for Black individuals.³ Therefore, USPSTF criteria that apply categories of age and smoking pack-years equally to everyone effectively ensure that Black-White disparities in screening eligibility will persist.

To move forward, a better definition of equity in the context of eligibility for cancer screening is needed. The goal is not to have the same proportion of Black and White individuals eligible because, if 1 group has a lower risk of lung cancer, then those individuals could experience net harm from screening. The same could apply to the goal of achieving an equal percentage of life-years gained across different groups. As an extreme example, consider 2 groups: in group A, everyone smokes 3 cigarettes per day, and, in group B, 10% smoke 30 cigarettes per day, and 90% have never smoked. Although many smoking-induced lung cancers would occur in both groups, practically no one in group A would have a sufficiently high risk to have net benefit from screening. If screening were offered to both groups in equal proportions, or to gain an equal percentage of life-years, then most screened individuals in group A would likely experience net harm. Instead, equity is better defined on an individual basis; when 2 people have the same anticipated screening benefit that outweighs the potential harms, both should be eligible, regardless of race and ethnicity.⁵

One strategy to achieve equity in this sense is to use prediction models that estimate individual lung cancer risk, with an agreed-on threshold, to determine screening eligibility. These models often include terms reflecting increased risk for Black individuals. However, the USPSTF declined to adopt this strategy, partly because of valid concerns that risk models prioritize older people and may be difficult to implement.² Also, these models were developed using data from cohort studies with more than 90% White participants and predict less accurately among Black individuals.

A second potential solution is to create USPSTF categories specifically for Black individuals. Before the 2021 recommendation was drafted, 1 analysis suggested lowering the pack-year threshold from 30 to 20 pack-years for Black individuals only.⁶ However, how then would issues of equity for individuals from other racial and ethnic groups be addressed? Would recommendations need to be stratified by sex or by family history of lung cancer?

A third solution is to apply a model that estimates individual predicted benefit from screening in terms of life-years gained, which deprioritizes screening for people with lower life expectancy.⁷ If this model were used to augment the 2021 USPSTF-eligible population with individuals who have high predicted benefit, then the aforementioned disparity in life-years gained might be nearly eliminated.³ However, a concern is that this model preferentially offers screening to people with longer life expectancy, while including an adjustment that reduces life expectancy for Black individuals. This also highlights that using life-years gained to quantify disparities may be problematic if Black individuals have shorter life expectancy Reducing screening for people with low life expectancy without systematically denying screening for Black individuals poses a conceptual challenge that disparities experts and ethicists might contribute to solving.

The onus is on the scientific community to find solutions for the problems facing existing approaches or to develop new ones. First, new tools could be developed and validated to predict lung cancer specifically among Black individuals by using data from cohort studies with strong representation from racial and ethnic minority groups. Researchers should consider that risk factors among Black participants may differ from those among White participants and may include environmental exposures or poverty-related factors.

In its 2021 recommendation statement,² the USPSTF cited the lack of implementation studies prospectively comparing the criteria of smoking pack-years and risk models as a reason for not endorsing the use of risk models. The ongoing International Lung Screening Trial and Yorkshire Lung Screening Trial should fill this evidence gap. However, separate implementation studies must demonstrate that prediction tools can be used successfully and efficiently in the US setting via integration into electronic health record systems. Since lung cancer screening is an individual decision that is preference sensitive for many individuals, research should examine the decision-making process specifically among Black individuals. The effect of new tools on screening uptake and psychological outcomes among Black individuals is of particular interest. More broadly, equitable eligibility for other racial and ethnic minority groups and across other dimensions, such as sex, socioeconomic status, and health status, must be ensured with a simultaneous focus on access, uptake, and other causes of screening disparities.

When the USPSTF next examines its recommendation for lung cancer screening, our hope is that the research community will have developed fit-for-purpose tools that can fully address disparities, along with clear evidence that they can be implemented. Transforming lung cancer screening guidelines to use such tools could be not just a health-improving act but also an antiracist one.