Lung Cancer Screening Guidelines Yield Racial, Ethnic Disparities

The use of low-dose computed tomography (CT) has demonstrated a more than 20% lung cancer-specific mortality reduction in landmark lung cancer screening trials. Based on the trial evidence and modeling efforts, the US Preventive Services Task Force (USPSTF) issued lung cancer screening guidelines in 2013 recommending annual low-dose CT for individuals aged 55 to 80 years who had a minimum cumulative smoking exposure of 30 pack-years. The USPSTF guidelines were updated in 2021 and recommended lowering the starting age to 50 years and cumulative smoking exposure to 20 pack-years. Compared with the 2013 guidelines, the revised criteria have been shown to reduce disparities in screening eligibility and performance between Black and White individuals. However, potential disparities among other racial and ethnic groups in the United States have been poorly examined.

Risk model-based screening may improve screening performance and further reduce racial and ethnic disparities compared with strategies based on age and exposure to tobacco smoke alone. Yet the leading risk prediction models were developed and validated using predominately White populations. This issue led Eunji Choi, PhD, and colleagues to examine the predictive performance of the Prostate, Lung, Colorectal, and Ovarian Screening Trial 2012 (PLCOm2012) model and evaluate racial and ethnic disparities and screening performance through risk-based screening using PLCOm2012 versus the revised USPSTF 2021 criteria across five racial and ethnic groups in the United States. Results were reported in JAMA Oncology [published online October 26, 2023; doi:10.1001/jamaoncol.2023.4447].

The Multiethnic Cohort Study included adults aged 45 to 75 years with a history of smoking who were enrolled in the study from 1993 to 1996. Participants were Black, Japanese American, Latino, Native Hawaiian/Other Pacific Islander, or White. Upon enrollment, the participants completed a questionnaire about their smoking history, sociodemographic factors (eg, education level and body mass index), and medical background, including a personal history of cancer or a family history of lung cancer.

The outcomes of interest were predictive performance; screening eligibility through the USPSTF 2021 criteria versus risk-based screening using PLCOm2012; eligibility-incidence (E-I) under each eligibility criterion, defined as the ratio between the total number of eligible participants versus incident lung cancer cases; and screening performance.

Of the 105,261 participants enrolled, 57% were men and 43% were women, and the mean age was 59.8 years. The cohort included 19,258 Black, 27,227 Japanese American, 21,383 Latino, 8368 Native Hawaiian/Other Pacific Islander, and 29,025 White individuals.

The researchers used the Surveillance, Epidemiology, and End Results cancer registry to identify which participants were diagnosed with lung cancer within 6 years of study enrollment. Based on the responses in the questionnaire, the authors evaluated which of the participants would have been available for lung cancer screening under either the updated USPSTF guidelines or the PLCOm2012 risk-based assessment.

Overall, 24% of the study participants would have been eligible for screening based on the 2021 USPSTF guidelines. However, differences were observed among the racial and ethnic groups. Data showed that 30.2% of White individuals would have qualified for screening compared with 25.5% of Japanese American, 21.5% of Native Hawaiian/Other Pacific Islander, 21.4% of Black, and 15.7% of Latino individuals.

When researchers calculated the E-I ratio using updated guidelines, they found that White participants had an E-I ratio of 20.3, while Black individuals had a ratio of 9.5. The researchers attributed the difference to the fact that fewer Black participants were eligible for screening (21.1% vs 30.2%) and had a higher 6-year incidence of lung cancer (2.2% vs 1.5%). Among other groups, a disparity in the E-I ratio between Native Hawaiian/Other Pacific Islander and White participants was observed (16.8 vs 20.3).

In contrast, the risk-based criteria using the PLCOm2012-Update (6-year risk ³1.3%) showed that the E-I ratio between Black individuals compared with White individuals was substantially reduced (15.9 vs 18.4; P<.001). This improvement was driven by increased screening eligibility among Black participants (35.7% vs 21.4% eligible for screening under the updated task force guidelines). The difference in E-I ratios between Native Hawaiian/Other Pacific Islander and White participants also improved (16.6 vs 18.4; P>.001). Minimal differences were seen in E-I ratios between White participants compared with other ethnic groups, including Japanese American (18.5) and Latino (16.0) participants.

Further analysis of risk-based screening through the PLCOm2012-Update compared with USPSTF 2021 criteria showed overall higher sensitivity (67.2% vs 57.7%) and a lower number needed to screen (26 vs 30) at similar specificity (76.6%).

The authors cited study limitations, including that the population samples in the cohort from California and Hawaii might not be reflective of the entire US population structure. Also, it remains unknown whether efficacy of screening (ie, reduction in lung cancer mortality) potentially varies by racial or ethnic group. Future research is warranted to investigate clinician- and individual-level barriers to undergoing lung cancer screening among individuals in high-risk racial and ethnic minority groups.

In conclusion, the researchers said, “Risk-based lung cancer screening using a validated risk prediction model may help reduce racial and ethnic disparities in lung cancer screening and improve screening efficiency across racial and ethnic groups in the [United States].”