Minorities, socioeconomically disadvantaged face higher risk of aggressive lung cancers

A study in the March issue of the American Journal of Roentgenology found that minority, socioeconomically disadvantaged, high-risk populations are may be more prone to developing late-stage and aggressive lung cancers than more privileged communities.

Researchers from the Keck School of Medicine at the University of Southern California and the Health Sciences Campus Community Partnerships at the USC Office of Civic Engagement aimed to analyze a population different than 2002 National Lung Screening Trial (NLST) participants by using lung cancer screening with low-dose CT (LDCT) technology. NLST participants identified as 91 percent white, 48 percent were current smokers, and a majority were of younger with higher socioeconomic status than the usual U.S. population eligible for lung cancer screening.

For the LDCT study, 329 eligible participants were referred from July 2015 to April 2017 through community partner clinics in a socioeconomically disadvantaged region of southern Los Angeles. All participants met National Comprehensive Cancer Network eligibility requirements to undergo necessary lung cancer screenings for the study.

Participants were an average age of 59 years old, 52 percent male and 84 percent black, with 66 percent obtaining a high school education or less. Additionally, the average pack years was 40, current smokers made up 81 percent of all and 31 percent reported having occupational exposure to one or more lung carcinogens, most commonly asbestos and diesel fumes.

“Our population’s low education status predisposes them to working in manual labor jobs that often involve regular exposure to noxious fumes and other hazardous materials that may further increase their risk for developing lung cancer,” wrote lead author Phillip Guichet, MD, from the Keck School of Medicine at USC, and co-authors. “Indeed, regular occupational exposure to known lung carcinogens is more common among black than white individuals, a reflection of the socioeconomic burdens of minority communities.”

Among other risk factors, 20 percent of participants reported a family history of lung cancer, and 20 percent reported being diagnosed with chronic obstructive pulmonary disease. Of the 329 eligible participants, 275 underwent LDCT baseline screening and the following Lung CT Screening Reporting and Data System (Lung-RADS) categories were assigned using baseline LDCT examinations:

• Category 1 or 2 in 86 percent of participants (negative findings).
• Category 3 in seven percent of participants (positive findings).
• Category 4A in four percent of participants (positive findings).
• Category 4B or 4X in three percent of participants (positive findings).

Overall, 29 percent of the 275 participants had “potentially clinically significant incidental findings” on their baseline LDCT screening, more than twice as much as found in the NLST study, researchers wrote.

“Although detection of clinically significant incidental findings may confer added value to a lung cancer screening program, a more immediate issue our program encountered was the coordination of proper follow-up and evaluation of these findings in communities with few and overburdened health care resources,” said Guichet et al. “It is unclear at this point whether detection of clinically significant findings in an under- served population will result in any morbidity or mortality benefits.”

Furthermore, 0.7 percent of participants were diagnosed lung cancer, including stage IIIB small cell lung carcinoma in one patient and stage IV lung cancer of unknown type in another. Comparatively, late-stage lung cancers made up a small percentage of all malignancies detected in the NLST, researchers wrote. However, both the LDCT and NLST studies had a similar percentage of positive baseline screens of all participants in either study (14 percent).

“Although our primary objective was to describe the preliminary screening results in this underserved population, successful completion of this goal has permitted a deeper analysis of the unique lung cancer risk factors, cancer profile, and socioeconomic issues regarding cancer screening and health care navigation in these communities,” according to the researchers. “Furthermore, implementation of a lung cancer-screening program targeting this population has afforded a valuable opportunity to evaluate the generalizability of the NLST’s results to the aggregate U.S. population eligible for lung cancer screening.”