Lung cancer screening models not all alike, new study finds

Racial disparities in lung cancer screening could be reduced by employing the risk predictor model PLCOm2012 instead of a more commonly used version that is more skewed toward Caucasians, according to new research conducted at the University of Illinois at Chicago and published in the Journal of Thoracic Oncology.

“Lung cancer is the leading cause of cancer mortality in the United States, and it disproportionally affects African American individuals with higher incidence, advanced stage at diagnosis and lower survival rates,” said Mary Pasquinelli, DNP, APRN, FNP-BC, lead author of the study. “African American ever-smokers are at increased risk for lung cancer compared to their white counterparts after adjusting for age and smoking history.

“African American individuals are more likely to start smoking at a later age, smoke fewer cigarettes per day, have a longer duration of smoking, are less likely to quit, and tend to be diagnosed at an earlier age.”

Every year about 200,000 people are diagnosed with lung cancer and 150,000 people die. Cigarette smoking is the number one cause of lung cancer, and it is linked to 80% to 90% of all lung cancers, according to the American Cancer Society.

The PLCOm2012 prediction model, which has been endorsed in several countries, including the United States, Germany, Australia and Canada, is based on data collected from the control arm of the Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial (PLCO), a randomized controlled trial studying screening to reduce cancer mortality. It incorporates 11 predictors, including sociodemographic, medical history, and four smoking exposure variables.

The predictors are: age, highest level of education obtained, body mass index (BMI), chronic obstructive pulmonary disease (COPD), personal history of cancer, family history of lung cancer, race/ethnicity, smoking status (former or current), average number of cigarettes smoked daily, number of years smoked, and duration of time having stopped smoking.

The study was conducted at UI Health, with the cases being between the years 2010-2019, with the data being collected until March 15, 2020.

Pasquinelli and her research team compared the screening sensitivities of the PLCOm2012 to those of the United States Preventive Services Task Force (USPSTF) – an independent, volunteer panel of national experts in prevention and evidence-based medicine­ – using six-year thresholds of more than or equal to 1.51%, 1.70% and 2.0%. The initial survey population included 1,050 lung cancer cases, which was then narrowed to 883 ever-smokers comprised of the following racial/ethnic makeup: 258 (29.2%) White; 497 (56.3%) African American; 69 (7.8%) Hispanic; 24 (2.7%) Asian; and 35 (4.0%) other.

Compared to the USPSTF criteria, the PLCOm2012 model increased the sensitivity for the African American cohort at lung cancer risk at all three thresholds for the six years, Pasquinelli said. The USPSTF criteria and the PLCOm2012 model with 1.70% risk threshold identified 62.4% and 66% of White cases, respectively, and 50.3% and 71.3% of African American cases, respectively.

The PLCOm2012 model improved sensitivity in both Whites and African American ever-smokers and eliminated the eligibility disparity, she said. Of the 64 African American ever-smokers who were ineligible due to USPSTF standards because their ages were less than 55 years, 23.4% would have qualified by the model with the risk threshold of 1.7%. Of 53 African American ever-smokers who were USPSTF-ineligible because they had quit smoking more than 15 years ago, 49.1% would have qualified by the PLCOm2012. Additionally, of the 193 African American ever-smokers who were USPSTF-ineligible because they had pack-years less than 30, 40.4% would have qualified by the PLCOm2012.

Current USPSTF guidelines, based on the National Lung Cancer Screening Trial, recommend annual screening using low dose computed tomography for individuals that meet the following criteria: ages 55-80 or 55-77 years, respectively; history of 30 or more pack years of cigarette smoking; and in former smokers having quit smoking within the past 15 years.

In lung cancer screening trials to date, African American ever-smokers have been underrepresented, Pasquinelli said. The USPSTF lung cancer screening criteria omits several potential high-risk factors, and a 30-year pack history is a “comparatively crude measure of an individual’s actual smoking exposure,” she said. “Thus the USPSTF criteria may exclude individuals who are at high risk for lung cancer and neglects them from the potential benefits of screening.

USPSTF guidelines are used to determine insurance coverage for lung cancer screening without cost sharing under the Affordable Care Act. This study gives evidence that the USPSTF guidelines need to be expanded to include a risk prediction model such as the PLCOm2012 in order to decrease racial disparities in lung cancer screening, Pasquinelli said.

“Our research found that the PLCOm2012 model was preferable over the USPSTF criteria at identifying African American ever-smokers for lung cancer screening. Broader use of the PLCOm2012 in racially diverse populations may help overcome disparities in lung cancer screening and outcomes.”

Study co-authors include: Martin Tammemagi, PhD, CancerCare Ontario, Canada; and Kevin Kovitz, MD; Marianne Durham, DNP; Zane Deliu, MS; Kayleigh Rygalski, BS; Li Liu, PhD; Matthew Koshy, MD; Patricia Finn, MD; and Lawrence Feldman, MD, all of UIC. Feldman is a member of the UI Cancer Center.

Share on facebook
Share on twitter

Translate »