Do Lung Cancer Guidelines Undercount Black Americans?

Despite findings that Black Americans are more likely to die of lung cancer than white Americans, current screening guidelines fail to properly count this population, according to new findings published in the International Association for the Study of Lung Cancer’s Journal of Thoracic Oncology.

Black people have different patterns of smoking and lung cancer. They are more likely to begin smoking at a later age, have a longer duration of smoking, are less likely to quit and are more likely to be diagnosed with lung cancer at an earlier age.

Yet current guidelines from the United States Preventive Services Task Force (USPSTF) recommend that individuals between ages 55 and 80 with a smoking history of 30 or more pack-years and who are either current smokers or who have quit smoking within the last 15 years be screened for lung cancer. Meanwhile, the Center for Medicare and Medicaid Services recommends screening such individuals between ages 55 and 77. (A pack-year is equal to smoking one pack containing 20 cigarettes every day for a year.)

Revisions are underway to lower the USPSTF recommended screening age to 50 and the number of pack-years to 20.

According to the Southern Community Cohort, a study of cancer and other major diseases, only 17% of African Americans who ever smoked would have met current USPSTF criteria compared with 31% of white Americans. This is despite research that shows Black ever-smokers are at greater risk for lung cancer than their white counterparts even after factoring in age and smoking history.

When researchers at the University of Illinois at Chicago followed up on the previous study, they analyzed a cohort of 1,050 patients with thoracic cancer (which includes lung cancer) from a cancer registry to determine whether each patient would have been eligible for screening according to the USPSTF criteria based on age, pack-years and quit time. (The cohort was eventually pared down to 883 ever-smokers, which included 258 white Americans, 497 Black Americans and 69 Hispanic people.)

This time, scientists used the PLCOm2012 lung cancer risk prediction model, which includes sociodemographic, medical history and four smoking exposure variables.

Compared with the USPSTF criteria, those of the PLCOm2012 had a greater sensitivity for African Americans at several different lung cancer risk thresholds. For example, at the 1.7% risk threshold of developing lung cancer over the next six years, PLCOm2012 identified 66% of cases among white people and 71.3% of cases among Black people. By contrast, USPSTF criteria at that risk threshold identified only 62.4% of white and 50.3% of Black cases.

Researchers also determined that 23.4% of the 64 Black Americans who were ineligible for USPSTF screening due to their age would have qualified according to the PLCOM2012 criteria. About 49% of the 53 Black ever-smokers who were ineligible for USPSTF screening because they had quit smoking more than 15 years ago would have been eligible using the PLCOM2012 model. In addition, 40.4% the 193 Black-ever smokers who didn’t meet the USPSTF criteria for screening because they had fewer than 30 pack-years would have qualified according to the criteria of the PLCOM2012 model.

“We found that the PLCOm2012 model was significantly more sensitive in selecting lung cancer patients as being eligible for screening the entire cohort,” said lead author Mary Pasquinelli, DNP, from the University of Illinois at Chicago. “Broader use of this model in racially diverse populations may help overcome disparities in lung cancer screening and outcomes.”