Have we removed racial disparity from lung cancer screening?

In March 2021, the US Preventive Services Task Force (USPSTF) issued revised lung cancer screening guidance. The new guidance expanded the age range for screening and lowered pack-year history. Alleviating racial disparities over access to lung cancer screening was one of the motivations underpinning the update.

Did the changes have their intended effect? Two studies have weighed whether the expansion ameliorated the issue, with one predicting enhanced access for at-risk individuals, and the other demonstrating reduced racial disparity.

Inside the changes

For adults between the ages of 50 and 80 who have a smoking history of 20 pack-years and either are current smokers or have quit within the last 15 years, the USPSTF recommends annual low-dose CT scans. Clinicians can discontinue screenings after 15 years of smoking cessation, or if the patient has a health issue that shortens life expectancy or limits the viability of lung surgery. Suggested screening ages had been 55 to 80 years, and pack-year history had been set at 30.

For clinical assessment, the USPSTF considers a pack-year “the equivalent of smoking an average of 20 cigarettes—1 pack—per day for a year.” If a patient falls within the age range and meets the pack-year criteria, the USPSTF says clinicians should engage patients in shared decision-making about whether to be screened. Discussions should cover benefits, harms, and limitations of screening. Clinicians can also advise those who currently smoke about cessation options.

“These differences are likely related to differences in smoking exposure (ie, prevalence of smoking) and related exposure to carcinogens in cigarettes,” the USPSTF wrote.

The low uptake of lung screenings adds to the complexity, as demonstrated in a 2019 study in the American Journal of Preventive Medicine. Researchers found that among 4,374 patients eligible for screening, 14.4% received a CT scan within the past year. Those who had insurance were more likely to receive scans, as were those with asthma or COPD. Of note, as of 2018, Blacks were 42% more likely than Whites to have asthma, according to the American Lung Association.

With the need to address the screening disparity rendered clearly, the question becomes whether the new guidelines had their intended effect. 

Narrowing the gap

Two studies indicate that the new guidelines are addressing the underlying racial disparity in lung cancer screening. 

The first is a 2022 study published in JAMA Oncology. Researchers compared the specificity and sensitivity of the revised USPSTF guidelines with those of similar screening criteria, noting differences by race. The study involved 912 patients with lung cancer, and 1,457 control patients. Ages ranged from 21 to 89.

Researchers applied USPSTF criteria from 2013 and 2021, along with the PLCOm2012 screening criteria, to see which patients would have qualified for lung screenings. Sensitivity was defined as the percentage of those with lung cancer who were screening-eligible, and specificity as the percentage of the control group who were ineligible for screening.

Overall, 68% of participants qualified for screening under PLCOm2012, and 65% were eligible under the 2021 USPSTF guidance. Under the 2013 USPSTF criteria, 49% would have been screened.

However, with the 2013 USPSTF criteria, a disproportionate number of eligible patients were White: 52% compared with 42% of the Black study participants. Researchers noted that “this racial disparity was absent” with the 2021 USPSTF criteria: 65% of White patients were eligible, as were 63% of Black patients.

In terms of specificity, the 2013 USPSTF criteria excluded more Black participants (70%) than White participants (61%). This leveled out under the 2021 USPSTF criteria, with 48% of White participants and 50% of Black patients excluded.

“This study suggests that the USPSTF 2021 guideline changes improve on earlier, fixed screening criteria for lung cancer, broadening eligibility and reducing the racial disparity in access to screening,” researchers concluded.

Expanding access

A 2021 study published in JAMA Network Open had similar findings. Researchers sought to determine whether the 2021 USPSTF guidelines lead to “a clinically meaningful change in the distribution of characteristics of individuals who are eligible for screening.”

The study involved patient data from five healthcare systems. All 341,163 participants, ranging in age from 50 to 80, had smoked and been healthcare system participants for 12 months or more. Non-smokers, and those with unclear smoking history, were not included.

Under the 2013 USPSTF recommendations, 34,528 participants were eligible for screening.

“Findings of the present study suggest that expanding the USPSTF recommendations for lung cancer screening eligibility is an important step toward minimizing disparities in lung cancer screening, but healthcare systems will still need to invest substantial resources to tailor outreach strategies and reduce barriers to lung cancer screening uptake for those with lower SES [socioeconomic status] and for racial and ethnic minority groups,” the researchers concluded.

Sources

1. Final Recommendation Statement. Lung Cancer: Screening. US Preventive Services Task Force. March 9, 2021.

2. Haiman CA, Stram DO, Wilkens LR, et al. Ethnic and racial differences in the smoking-related risk of lung cancer. N Engl J Med. 2006;354(4):333-342.

3. Pu CY, Lusk CM, Neslund-Dudas C, et al. Comparison between the 2021 USPSTF lung cancer screening criteria and other lung cancer screening criteria for racial disparity in eligibility. JAMA Oncology. Published online January 13, 2022.

4. Ritzwoller DP, Meza R, Carroll NM, et al. Evaluation of population-level changes associated with the 2021 US Preventive Services Task Force lung cancer screening recommendations in community-based health care systems. JAMA Netw Open. 2021;4(10):e2128176.

5. Zahnd WE, Eberth JM. Lung cancer screening utilization: a behavioral risk factor surveillance system analysis. Am J Prev Med. 2019;57(2):250-255.