Risk Model-Based Lung Cancer Screening and Racial and Ethnic Disparities in the US

Abstract

Importance: The revised 2021 US Preventive Services Task Force (USPSTF) guidelines for lung cancer screening have been shown to reduce disparities in screening eligibility and performance between African American and White individuals vs the 2013 guidelines. However, potential disparities across other racial and ethnic groups in the US remain unknown. Risk model-based screening may reduce racial and ethnic disparities and improve screening performance, but neither validation of key risk prediction models nor their screening performance has been examined by race and ethnicity.

Objective: To validate and recalibrate the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial 2012 (PLCOm2012) model-a well-established risk prediction model based on a predominantly White population-across races and ethnicities in the US and evaluate racial and ethnic disparities and screening performance through risk-based screening using PLCOm2012 vs the USPSTF 2021 criteria.

Design, setting, and participants: In a population-based cohort design, the Multiethnic Cohort Study enrolled participants in 1993-1996, followed up through December 31, 2018. Data analysis was conducted from April 1, 2022, to May 19. 2023. A total of 105 261 adults with a smoking history were included.

Exposures: The 6-year lung cancer risk was calculated through recalibrated PLCOm2012 (ie, PLCOm2012-Update) and screening eligibility based on a 6-year risk threshold greater than or equal to 1.3%, yielding similar eligibility as the USPSTF 2021 guidelines.

Outcomes: Predictive accuracy, screening eligibility-incidence (E-I) ratio (ie, ratio of the number of eligible to incident cases), and screening performance (sensitivity, specificity, and number needed to screen to detect 1 lung cancer).

Results: Of 105 261 participants (60 011 [57.0%] men; mean [SD] age, 59.8 [8.7] years), consisting of 19 258 (18.3%) African American, 27 227 (25.9%) Japanese American, 21 383 (20.3%) Latino, 8368 (7.9%) Native Hawaiian/Other Pacific Islander, and 29 025 (27.6%) White individuals, 1464 (1.4%) developed lung cancer within 6 years from enrollment. The PLCOm2012-Update showed good predictive accuracy across races and ethnicities (area under the curve, 0.72-0.82). The USPSTF 2021 criteria yielded a large disparity among African American individuals, whose E-I ratio was 53% lower vs White individuals (E-I ratio: 9.5 vs 20.3; P < .001). Under the risk-based screening (PLCOm2012-Update 6-year risk ≥1.3%), the disparity between African American and White individuals was substantially reduced (E-I ratio: 15.9 vs 18.4; P < .001), with minimal disparities observed in persons of other minoritized groups, including Japanese American, Latino, and Native Hawaiian/Other Pacific Islander. Risk-based screening yielded superior overall and race and ethnicity-specific performance to the USPSTF 2021 criteria, with higher overall sensitivity (67.2% vs 57.7%) and lower number needed to screen (26 vs 30) at similar specificity (76.6%).

Conclusions: The findings of this cohort study suggest that risk-based lung cancer screening can reduce racial and ethnic disparities and improve screening performance across races and ethnicities vs the USPSTF 2021 criteria.

Figure 1.. Predictive Performance of the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial 2012 (PLCOm2012)-Update Model by Race and Ethnicity

The discriminatory ability of the PLCOm2012-Update is evaluated by area under the curve (AUC). A, Japanese American (n = 27 727). B, Latino (n = 21 383). C, African American (n = 19 258). D, Native Hawaiian/Other Pacific Islander (n = 8368). Calibration between the observed and predicted probability of developing a 6-year lung cancer risk is presented with a calibration plot and calibration slope. The Brier score measures the accuracy of probabilistic predictions in the range of 0 and 1, and the lower the Brier score, the better the predictions are calibrated. All estimates are based on 10-fold cross-validation. Calibration measures the overall agreement between the observed and predicted outcomes by plotting a calibration curve between the observed vs predicted event status in groups by quantiles (eg, deciles) of the predicted probabilities. In this study, calibration ability was further quantified using the slope of the fitted linear regression between the means of observed and predicted probabilities across the decile groups. Perfect agreement between observed and predicted probability over deciles is shown by a slope of 1. The calibration slope is a simple, straightforward metric for evaluating overall calibration, but the graphic calibration plot across risk decile groups should also be taken into account because good calibration is dependent on a risk threshold of interest. The performance of PLCOm2012-Update on the White and overall cohorts is shown in eFigure 4 in Supplement 1.

Figure 2.. Racial Disparities in the Eligibility-Incidence (E-I) Ratio Through the US Preventive Services Task Force (USPSTF) 2021 and Risk-Based Screening (Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial 2012 [PLCOm2012]-Update Model 6-Year Risk ≥1.3%) Criteria

A, Screening eligibility to 6-year lung cancer incidence (E-I) ratio is compared between the USPSTF 2021 criteria and risk-based criteria using the PLCOm2012-Update across different races and ethnicities. In risk-based screening, individuals were deemed eligible for lung cancer screening if their predicted 6-year risk of lung cancer using the PLCOm2012-Update equaled or exceeded the risk threshold (≥1.3%). B, The percent difference of the E-I ratio between the White and other racial and ethnic groups is calculated as follows: ([E-I ratio of a racial or ethnic group – E-I ratio of White] / [E-I ratio of White] x 100).

Figure 3.. Screening Performance Through the US Preventive Services Task Force (USPSTF) 2021 and the Risk-Based Screening (Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial 2012 [PLCOm2012]-Update 6-Year Risk ≥1.3%) Criteria

In the risk-based screening criteria, participants are eligible for screening if their predicted 6-year risk of lung cancer using the PLCOm2012-Update equals or exceeds the risk threshold (≥1.3%). A, Screening efficiency performance was quantified by screening sensitivity (the number of screening-eligible participants among lung cancer cases). B, Specificity (the number of screening-ineligible participants among non–lung cancer cases). C, The number needed to screen (NNS) to detect 1 lung cancer (the total number of screening-eligible cases divided by the number of screening-eligible lung cancer cases).