By Kim L. Sandler, MD, Melinda C. Aldrich, MPH, PhD, and Jeffrey D. Blume, PhD
Posted: April 16, 2020
IN REFERENCE TO: Aldrich MC, Mercaldo SF, Sandler KL, Blot WJ, Grogan EL, Blume JD. Evaluation of USPSTF Lung Cancer Screening Guidelines Among African American Adult Smokers. JAMA Oncol. 2019 Jun 27. [Epub ahead of print].
Lung cancer screening, which includes a shared decision-making visit and low-dose computed tomography (CT) scan of the chest, is fully covered for those who meet eligibility criteria by Affordable Care Actcompliant insurers. Eligibility criteria are based on the patient population that was selected for the National Lung Screening Trial (NLST).1 The NLST found a 20% reduction in lung cancer mortality for low dose CT imaging compared to chest x-ray after three annual scans. These results led to a Class B recommendation from the United States Preventive Services Task Force and to current screening guidelines.2 These guidelines, however, exclude a large number of patients who are diagnosed with lung cancer by limiting screening to smokers aged 55 to 80, who have a 30 pack–year smoking history and who quit no more than 15 years prior to screening.3,4 A recent sub-study analysis of the NLST data demonstrated that African Americans receive the most benefit from lung screening, yet this population fails to meet eligibility criteria more often than Caucasians.5,6
JAMA Oncology recently published “Evaluation of USPSTF Lung Cancer Screening Guidelines Among African American Adult Smokers.” This research paper evaluated lung cancer screening eligibility among more than 48,000 adult smokers who were prospectively enrolled primarily from community health centers across 12 southern states from March 2002 through September 2009. Two-thirds of participants were African American. Among participants diagnosed with lung cancer, a significantly smaller percentage of African-American smokers diagnosed with lung cancer would have been eligible for screening compared to Caucasian smokers diagnosed with lung cancer (32% vs 56%). This racial disparity in screening eligibility can be eliminated by simple modifications to current eligibility criteria for African Americans. By decreasing the pack–year smoking requirement to 20 years and beginning screening at age 50, sensitivity for lung cancer screening would improve for African Americans so that it would be almost identical to sensitivity among Caucasian smokers.5 Specificity for lung cancer screening would be similarly aligned with Caucasian smokers as well.
In the 8 years since the publication of the NLST, there have been several additional randomized controlled trials that have shown even greater mortality benefit with annual screening for lung cancer.7,8 Follow-up studies from the NLST and subgroup analyses have also shown that the morbidity and mortality benefit from screening is even better than initially reported.9 This, in addition to the racial disparities in current eligibility criteria, should be enough to consider revisions to the current screening guidelines.
Novel Screening Approaches
Many researchers have suggested that screening should be based on a risk-prediction model rather than simply age and smoking history.10-12 At the 2019 World Conference on Lung Cancer in Barcelona, Spain, there were 70 posters presented on lung cancer screening and early detection. Of these, 12 proposed algorithms based on patient demographics and/or CT imaging findings to refine screening eligibility. At the 2018 World Conference on Lung Cancer, several researchers presented algorithms for screening and emphasized how improved mortality benefit and reduced false-positive rates could be achieved by selecting a screening population based on risk-based eligibility. Importantly, several models, such as the PLCOm2012 model, have shown that risk prediction for lung cancer is improved in part by including race as part of the selection algorithm.10,11 However, a recent paper suggested that screening based on risk estimates may substantially increase overdiagnosis,13 so additional evaluation is necessary.
Lung cancer screening works by facilitating the early detection of lung cancer in asymptomatic patients who otherwise may only have been diagnosed with late-stage disease after the development of symptoms. Screening for lung cancer with low-dose CT has been proven now to provide an even greater mortality benefit than what was originally published in the NLST.7,8,14 Low-dose CT can find lung cancer with minimal risk to patients. Although the test is not perfect, it is continually being improved, with more advanced CT technology and machine learning being incorporated to better distinguish benign nodules from malignant disease.5,15
Although the research surrounding selection algorithms is promising, we should not deny lung cancer screening to patient groups at increased risk. We can begin by offering screening to patients who we know are routinely excluded, particularly high-risk African Americans who develop lung cancer at younger ages and with less tobacco exposure than their Caucasian counterparts. This is a critical step in reducing the racial disparities that exist in lung cancer survival. ✦
About the Authors: Dr. Sandler is assistant professor in the Department of Radiology at Vanderbilt University Medical Center and co-director of the Vanderbilt Lung Screening Program. Dr. Aldrich is assistant professor in the Department of Medicine at Vanderbilt University Medical Center. Dr. Blume is an associate professor in the Department of Biostatistics and Biomedical Informatics at Vanderbilt University Medical Center.
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