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USPSTF Lung Cancer Screening Guidelines Too Conservative for African Americans, New Study Suggests

NEW YORK — Current US Preventive Services Task Force guidelines for lung cancer screening in smokers may not be appropriate for African Americans, prompting the need for race-specific changes to screening eligibility criteria, according to a new study out of Vanderbilt University.

The study specifically found that the USPSTF's smoking history guidelines used to determine eligibility for CT screens is too conservative for African Americans, and that a change in this criterion could increase screenings for African American smokers at high risk for lung cancer.

In 2011, the National Cancer Institute released the results of the National Lung Screening Trial (NLST), which showed that yearly screening with low-dose computed tomography (CT) in heavy smokers reduced lung cancer mortality by up to 20 percent versus disease detection using standard chest X-ray. In light of these and other findings, the USPSTF issued guidelines recommending CT screening for individuals who are 55 to 80 year of age, have a 30 pack-per-year smoking history, and either currently smoke or have quit within the past 15 years.

However, only 4 percent of the smoker population analyzed in the NLST was African American, Vanderbilt researchers noted in a paper appearing today in JAMA Oncology. As a result, the NLST failed to account for racial differences in smoking patterns — namely that adult racial minorities tend to smoke fewer cigarettes versus white smokers — and African Americans' elevated risk of lung cancer compared with other races.

"These differences in smoking patterns and lung cancer risk suggest that the USPSTF lung cancer screening guidelines are not optimal for African American adults and could be improved," the investigators stated. 

To test their hypothesis, the scientists examined a cohort of 48,364 smokers — including 32,463 African Americans and 15,901 whites — from the prospective Southern Community Cohort Study (SCCS), which tracked adults visiting community health centers across 12 Southern US states between early 2002 and late 2009. 

Based on current USPSTF recommendations, 5,654 — or 17 percent — of the African Americans in the SCCS were eligible for lung cancer screening compared with 4,992 — or 31 percent — of whites. Among the 791 African American and 478 white smokers who were diagnosed with lung cancer over the study's 12-year observation period, just 32 percent of African Americans were eligible for screening compared with 56 percent of whites.

According to the researchers, this disparity is largely due to the differences in the age of diagnosis and smoking level between the racial groups. 

"A significantly greater percentage of African American smokers [versus] white smokers did not meet the minimum 30-pack-year requirement for screening," they wrote. "African American smokers were also more likely than white smokers to be diagnosed with lung cancer at an earlier age compared with the USPSTF-required minimum age of 55 years and thus were ineligible for screening."

But by revising the USPSTF guidelines to lower the smoking pack-per-year criterion to 20 from 30, the number of African Americans in the SCCS cohort who would be eligible for screening increased to nearly 29 percent, with the eligibility of those African Americans diagnosed with lung cancer increasing to 49 percent.

The combination of the lower pack-per-year requirement and a reduction in the minimum age criterion to 50 for African Americans, meantime, would increase the screening eligibility of African Americans diagnosed with lung cancer to almost 58 percent.

Overall, the findings indicate that "existing USPSTF lung cancer screening guidelines … [are not] optimized for African American smokers and may result in a widening of racial disparities in late-stage diagnosis, potentially leading to higher mortality and worse outcomes among African American persons with lung cancer," the researchers concluded. "Race-specific adjustment of pack-year criteria in lung cancer screening guidelines would result in more equitable screening for African American smokers at high risk for lung cancer."

The researchers noted a number of limitations to their study, including that smoking information was self-reported, a lack of information on actual lung screening use, and missing smoking and race information for 5,566 SCCS participants.