Abstract
Introduction
Eligibility criteria for lung cancer screening based solely on age and smoking history are less sensitive than validated risk prediction models. The U.S. Preventive Services Task Force (USPSTF) has proposed new guidelines to improve the sensitivity for selecting high-risk individuals and to decrease race disparity. In this retrospective study, termed the Chicago Race Eligibility for Screening Cohort, we compare the sensitivity of the proposed USPSTF2020 criteria versus the PLCOm2012 risk prediction model for selecting a racially diverse lung cancer population with a smoking history for lung cancer screening.
Methods
This Chicago Race Eligibility for Screening Cohort study applies the PLCOm2012 model with a risk threshold of 1.0%/6 years and the USPSTF2020 criteria (age 50–80 y, pack-years ≥ 20 y, quit-years ≤ 15 y) to 883 individuals with a smoking history diagnosed with having lung cancer.
Results
The PLCOm2012 was more sensitive than the USPSTF2020 overall (79.1% versus 68.6%, p < 0.0001) in White (81.5% versus 75.4%, p = 0.029) and in African American (82.8% versus 70.6% p < 0.0001) individuals. Of the total cohort, 254 (28.8%) would not have qualified owing to less than 20 pack-years, quit-time of more than 15 years, and age less than 50 years. Of these 254 cases, 40% would have qualified by the PLCOm2012 model. For the 20 pack-year criterion, of the 497 African American individuals, 19.3% did not meet this criterion, and of these, an additional 31.3% would have qualified by the PLCOm2012 model (p = 0.002).
Conclusions
Although more sensitive than USPSTF2013, the proposed USPSTF2020 draft guidelines still have a race disparity in eligibility for screening. This study provides “real world” evidence that use of the PLCOm2012 risk prediction model eliminates this race disparity.
Keywords
Introduction
Lung cancer is the leading cause of cancer death in the United States.
1
The National Lung Screening Trial revealed a 20% reduction in lung cancer mortality with low-dose computed tomography (CT) compared with chest radiograph in high-risk individuals between the ages of 55 and 74 years, who currently smoke or quit within the past 15 years, with a smoking history of greater than or equal to 30 pack-years.2
The Dutch-Belgian lung screening trial was a randomized trial comparing CT screening versus no screening in individuals aged 50 to 74 years and a smoking history of greater than or equal to 15 cigarettes a day for more than or equal to 25 years or greater than or equal to 10 cigarettes a day for more than or equal to 30 years and quit-time of less than 10 years. The Dutch-Belgian lung screening trial found a mortality benefit of greater than or equal to 26%.3
The current U.S. Preventive Services Task Force (USPSTF) 2013 lung screening guidelines based on the National Lung Screening Trial define eligible individuals as aged 55 to 80 years with a greater than or equal to 30 pack-year smoking history who currently smoke or have quit within the past 15 years.4
The USPSTF has proposed new guidelines to improve the sensitivity for selecting high-risk individuals and to decrease race disparity. A draft of the proposal of these guidelines (USPSTF2020) lowers the age limit to 50 years and pack-year smoking history to 20 years for those who currently smoke or those who have quit within the past 15 years.5
US Preventive Services Task Force
Draft recommendation statement: lung cancer screening July 7.
Draft recommendation statement: lung cancer screening July 7.
https://www.uspreventiveservicestaskforce.org/uspstf/document/draft-decision-analysis/lung-cancer-screening1
Date: 2020
Date accessed: October 22, 2020
African American individuals who have a smoking history have a higher risk of lung cancer despite accumulating fewer pack-years compared with their White counterparts and are less likely to meet the USPSTF2013 guidelines.
6
In our previous study of 883 lung cancer cases with a history of smoking, the USPSTF2013 identified for screening 52.3% of this entire cohort, with 50.3% African American and 62.4% White individuals, whereas the PLCOm2012 risk prediction model at a 1.7%/6-year risk threshold identified 62.1% of this cohort, with 61.0% African American and 67.4% White individuals.6
Although we revealed that compared with the USPSTF2013 guidelines, the PLCOm2012 risk prediction model is more sensitive and decreases race disparity, the USPSTF2020 proposed guidelines also aim to increase sensitivity and decrease race disparity.In this retrospective study, termed the Chicago Race Eligibility for Screening Cohort, we compare the sensitivity of the proposed USPSTF2020 criteria versus the PLCOm2012 risk prediction model for selecting African American individuals with a smoking history for screening. The aim of this study is to provide evidence for the most optimal lung screening method that eliminates race disparities.
Material and Methods
The material and methods have been described previously.
6
Briefly, the Chicago Race Eligibility for Screening Cohort study applies the PLCOm2012 model with a risk threshold of 1.0%/6 years and the USPSTF2020 criteria (age 50–80 y, pack-years ≥ 20 y, quit-years ≤ 15 y) to a sequential series of 883 individuals with a smoking history diagnosed with having lung cancer at a large urban academic medical center.6
The PLCOm2012 1.0%/6 years threshold was chosen because Cancer Intervention and Surveillance Modeling Network microsimulation modeling found that it selected a similar number for screening as did the USPSTF2020 criteria.7
This study (2018-0491) met the requirements for waiver of informed consent which was approved by the University of Illinois at Chicago Institutional Review Board.Cancer Intervention and Surveillance Modeling Network CISNET, Lung Cancer Working Group. Evaluation of the benefits and harms of lung cancer screening with low-dose computed tomography: a collaborative modeling study for the U.S. Preventive Services Task Force. https://cisnet.cancer.gov/lung. Accessed November 13, 2020.
Results
This cohort was previously described (Supplementary Table 1).
6
The PLCOm2012 was significantly more sensitive than the USPSTF2020 overall (79.1% versus 68.6%, p < 0.0001) in White (81.5% versus 75.4%, p = 0.029) and African American individuals (82.8% versus 70.6% p < 0.0001) (Table 1). Overall, 32 cases would have been missed by PLCOm2012 and detected by USPSTF2020 criteria, whereas 125 cases would have been detected by PLCOm2012 and missed by USPSTF2020 (ORMcNemar = 3.91, 95% confidence interval [CI]: 2.63–5.95). In White individuals, the comparable numbers are 16 and 32 (ORMcNemar = 2.00, 95% CI: 1.07–3.90), whereas in African American individuals the comparable numbers are 9 and 69 (ORMcNemar = 7.67, 95% CI: 3.81–17.47). Applying the PLCOm2012 model, the White versus African American difference in sensitivity is 1.3% and is higher in the African American cohort (p = 0.61), whereas applying the USPSTF2020, the difference is 4.8% and is higher in the White cohort (p = 0.14).Table 1Sensitivity (%) of the USPSTF2020 Draft Criteria Versus the PLCOm2012 Risk Prediction Model for Finding Lung Cancer Cases Eligible for Screening, Stratified by Race (NAll = 883, NWhite = 258, NAfrican American = 497)
| Sample | USPSTF2020 % | PLCOm2012 ≥1.0%/6 y % | OR PLCOm2012 vs. USPSTF2020 | p Value |
|---|---|---|---|---|
| All | 68.6 | 79.1 | 3.91 (2.63–5.95) | <0.0001 |
| White | 75.4 | 81.5 | 2.00 (1.07–3.90) | 0.029 |
| African American | 70.6 | 82.8 | 7.67 (3.81–17.47) | <0.0001 |
Note: USPSTF2020 draft guidelines for lung cancer screening (age 50–80 y, ≥20 pack-years, smoking quit-time ≤15 y).
CISNET, Cancer Intervention and Surveillance Modeling Network; USPSTF, U.S. Preventive Services Task Force.
a CISNET microsimulation modeling revealed that a PLCOm2012 greater than or equal to 1.0%/6-yr threshold would find a similar number to be eligible as the USPSTF2020 draft criteria.2
b OR is McNemar’s for discordant pairs.
c p value by McNemar’s exact test. The p values are based on applying the summary proportions obtained from multiplying imputed data sets to the actual size of the study sample and subsamples.
Table 2 presents the number and proportion of lung cancer cases that failed to qualify by the USPSTF2020 criteria stratified by race and of these, the proportion of cases that would have qualified by the PLCOm2012 criteria. Of the total cohort of 883 cases, 254 (28.8%) would not have qualified owing to less than 20 pack-years, quit-time of more than 15 years, and age less than 50 years. Of these 254 cases, 40% would have qualified by the PLCOm2012 model. For the 20 pack-year criterion, of the 497 African American individuals, 97 (19.3%) did not meet this criterion and of these, an additional 30 (31.3%) in this group would have qualified by applying the PLCOm2012 model (p = 0.002). The quit-time criterion of more than 15 years negatively affected the screening eligibility of White and African American patients similarly, that is, 33 of 250 White (12.8%) and 53 of 497 African American (10.7%) (p = 0.383). By applying the PLCOm2012 model, approximately 60% of both White and African American individuals not eligible by the quit-time criterion would have qualified. In terms of age less than 50 years, (39 of 883) 4.4% of the entire cohort would have been screening ineligible by the USPSTF2020 criteria and of these 25% would have qualified by the PLCOm2012 model.
Table 2The Number and Proportion (in Round Brackets) of Individuals Not Meeting USPSTF 2020 Draft Criteria by Eligibility Rules and Proportion That Would Have Been Eligible by PLCOm2012 Greater Than or Equal to 1.0%/6 year [in Square Brackets], by Race
| Eligibility Criteria | Overall Sample | White | African American | p Value |
|---|---|---|---|---|
| Pack-years <20 y | 162/883 (18.3%) [24.0%] | 27/258 (10.5%) [22.5%] | 96/497 (19.3%) [31.3%] | 0.002 |
| Quit-time >15 y | 125/883 (14.2%) [50.2%] | 33/258 (12.8%) [60.6%] | 53/497 (10.7%) [59.2%] | 0.383 |
| Age <50 y | 39/883 (4.4%) [25.0%] | 12/258 (4.7%) [29.2%] | 23/497 (4.6%) [22.8%] | 0.998 |
| Age >80 y | 43/883 (4.9%) [91.9%] | 12/258 (4.7%) [95.8%] | 17/497 (3.4%) [86.8%] | 0.404 |
| Age <50 or >80 y | 82/883 (9.3%) [60.1%] | 24/258 (9.3%) [62.5%] | 40/497 (8.0%) [50.0%] | 0.557 |
| By any of the first 3 criteria listed | 254/883 (28.8%) [40.3%] | 58/258 (22.5%) [45.5%] | 138/497 (27.8%) [44.6%] | 0.116 |
Note: Percentages are based on all 20 imputed data sets, whereas the numbers presented represent one set, and therefore, they do not necessarily match perfectly.
USPSTF, U.S. Preventive Services Task Force.
a The overall category includes non-White and non-African American.
b The p values are for chi-square test of difference in proportion ineligible by criteria between Whites and African Americans.
c These summary statistics exclude USPSTF–ineligible individuals because they were greater than 80 years and because their health status was uncertain regarding their ability to undergo curative surgery or life expectancy.
Discussion
The USPSTF recently published their 2020 proposed draft guidelines on the eligibility for lung cancer screening with low-dose CT scan. Compared with the USPSTF2013 guidelines, the 2020 criteria would lower the restriction on smoking history from 30 to 20 pack-years and the age limit from 55 to 50 years. These changes are predicted to identify more high-risk individuals and result in an overall further decrease in lung cancer mortality; however, there will still likely be race disparities. Our study reveals that the USPSTF2020 criteria select a higher percentage of White versus African American patients with lung cancer for screening. The PLCOm2012 risk prediction model (≥1.0%/6-y threshold) is more sensitive and has no race disparity. Although, the USPSTF2020 White-African American sensitivity difference only trended to statistical significance in our limited sample, a 4.8% difference applied nationally would lead to substantial race disparity.
As it would be beneficial for the USPSTF (and the Centers for Medicare and Medicaid) to remove the 15 year-quit criteria so as to not penalize those who have successfully quit smoking, the PLCOm2012 does not have a limit on age, pack-years, or quit-time, providing an optimal screening modality for high-risk individuals who do not meet the USPSTF guidelines.
6
Consistent with the known trend that African American individuals have less smoking history than their White counterparts, a race disparity was found in that a statistically significantly higher percentage of African American compared with White patients did not meet the 20 pack-year criterion. For the other two USPSTF2020 criteria, that is, age less than 50 years and quit-years of more than 15 years, there was no race disparity found and the PLCOm2012 model would have selected for screening an additional 25% and 50% of these high-risk individuals, respectively.The American Thoracic Society recently released an official statement addressing disparities in lung cancer screening supporting screening eligibility assessment that includes both the USPSTF2020 guidelines and risk prediction models.
8
The USPSTF2020 draft guidelines discuss the benefits of risk prediction models with evidence from studies using simulation modeling. In addition, evidence from “real world” data is quickly accumulating which also supports risk prediction model implementation.9
, 10
, 11
Here, we provide additional “real world” evidence and reveal that the PLCOm2012 risk prediction model at a greater than or equal to 1%/6-year risk threshold seems to effectively eliminate race disparity in lung cancer screening.Supplementary Data
- Supplemental Table 1
References
- Cancer statistics, 2020.CA Cancer J Clin. 2020; 70: 7-30
- Reduced lung-cancer mortality with low-dose computed tomographic screening.New Eng J Med. 2011; 365: 395-409
- Reduced lung-cancer mortality with volume CT screening in a randomized trial.N Engl J Med. 2020; 382: 503-513
- US Preventive Services Task Force. Screening for lung cancer: U.S. Preventive Services Task Force recommendation statement.Ann Intern Med. 2014; 160: 330-338
- Draft recommendation statement: lung cancer screening July 7.https://www.uspreventiveservicestaskforce.org/uspstf/document/draft-decision-analysis/lung-cancer-screening1Date: 2020Date accessed: October 22, 2020
- Risk prediction model versus United States Preventive Services Task Force lung cancer screening eligibility criteria: reducing race disparities.J Thorac Oncol. 2020; 15: 1738-1747
Cancer Intervention and Surveillance Modeling Network CISNET, Lung Cancer Working Group. Evaluation of the benefits and harms of lung cancer screening with low-dose computed tomography: a collaborative modeling study for the U.S. Preventive Services Task Force. https://cisnet.cancer.gov/lung. Accessed November 13, 2020.
- Addressing disparities in lung cancer screening eligibility and healthcare access. An official American Thoracic Society statement.Am J Respir Crit Care Med. 2020; 202: e95-e112
Darling GE, Tammemägi MC, Schmidt H, et al. Organized lung cancer screening pilot: informing a province-wide program in Ontario, Canada [e-pub ahead of print]. Ann Thorac Surg. https://doi.org/10.1016/j.athoracsur.2020.07.051. Accessed November 16, 2020.
- Implementing lung cancer screening: baseline results from a community-based ‘Lung Health Check’ pilot in deprived areas of Manchester.Thorax. 2019; 74: 405-409
- PL02.02 lung cancer screenee selection by USPSTF versus PLCOm2012 criteria—interim ILST findings.J Thorac Oncol. 2019; 14: S4-S5
Article info
Publication history
Published online: December 29, 2020
Accepted:
December 19,
2020
Received in revised form:
December 18,
2020
Received:
November 27,
2020
Footnotes
Disclosure: Dr. Tammemägi developed the PLCOm2012 lung cancer risk prediction models. The model is open access and is available free of charge to noncommercial users. For commercial users, licensing has been assigned to Brock University. To date, Dr. Tammemägi has not received any money for use of the PLCOm2012 model nor does he anticipate any payments in the future. The remaining authors declare no conflict of interest.
Identification
Copyright
© 2020 The Authors. Published by Elsevier Inc. on behalf of the International Association for the Study of Lung Cancer.
User license
Creative Commons Attribution – NonCommercial – NoDerivs (CC BY-NC-ND 4.0) | How you can reuse 
Elsevier's open access license policy
Creative Commons Attribution – NonCommercial – NoDerivs (CC BY-NC-ND 4.0)
Permitted
For non-commercial purposes:
- Read, print & download
- Redistribute or republish the final article
- Text & data mine
- Translate the article (private use only, not for distribution)
- Reuse portions or extracts from the article in other works
Not Permitted
- Sell or re-use for commercial purposes
- Distribute translations or adaptations of the article
Elsevier's open access license policy
