August 24, 2021 — The mortality benefit of low-dose CT (LDCT) lung cancer screening programs could be improved significantly if more Black people who are eligible to be screened participate, according to research published online August 24 in JAMA Network Open.
In a secondary analysis of data from the National Lung Screening Trial (NLST), a research team led by Dr. Ashley Prosper of the David Geffen School of Medicine at the University of California, Los Angeles estimated the outcomes for CT lung cancer screening by creating hypothetical screening populations with varying distributions of Black individuals, women, and current smokers.
The group found that CT lung screening could offer an even greater reduction of lung cancer mortality if the percentage of Black participants were increased to reflect the share of Black individuals in the overall U.S. population.
“The potential to achieve greater reductions in lung cancer mortality than originally estimated by the NLST with the inclusion of more Black participants stresses the critical importance of improving access to lung cancer screening for Black current and former smokers,” the authors wrote.
Although the benefits of CT lung screening are now well accepted overall, the case for its importance for Black people who are current or former smokers has been based largely on analyses of clinical screening programs, according to the researchers.
“These descriptive analyses provide important insights into the effects of screening in eligible Black participants, yet clinical trials remain the criterion standard in the assessment of the efficacy of clinical interventions,” the authors wrote.
As a result, Prosper and colleagues sought to estimate how CT lung screening could affect lung cancer and all-cause mortality in populations with greater proportions of Black screening participants than the NLST. Using a technique called transportability analysis, they estimated outcomes among hypothetical populations by varying the distributions of Black individuals, women, and current smokers.
In the original NLST study, 4.4% of the study population was Black — far below the percentage of Black people in the U.S. population at large. The researchers found that increasing the percentage of Black participants in a hypothetical CT lung screening population to 13.4% — equivalent to U.S. census data — resulted in a higher reduction of lung cancer mortality.
|Improvement in lung cancer mortality from LDCT screening|
|NLST trial overall (4.4% of Black participants)||A hypothetical screening population in which 13.4% were Black|
|Hazard ratio for lung cancer mortality||0.84||0.8|
What’s more, the team found that the hazard ratio for mortality dropped even further to 0.68 in a hypothetical population with a higher proportion of men or current smokers, along with a higher proportion (60%, including 20%-40% women) of Black individuals.
“Even with the myriad barriers to enrollment in and ultimately adherence to lung screening with LDCT, extrapolation of NLST results to diverse populations with increased proportions of Black screening participants is nonetheless encouraging,” the authors concluded. “The potential to achieve greater reductions in lung cancer
mortality than originally estimated by the NLST with the inclusion of more Black participants stresses the critical importance of working to improve access to lung cancer screening for Black current and former smokers.”
In an accompanying editorial, Dr. Christopher Lathan of the Dana-Farber Cancer Institute in Boston said that the research is elegant and thought-provoking.
“Now we just need the will to build our trials and interventions to include historically marginalized communities prospectively even when there is not a global pandemic and sustain this awareness of systemic inequity moving forwards,” Lathan wrote. “Lives depend on it.”