USPSTF’s Lung Cancer Screening Recs Tied to Thousands Fewer Deaths

Significantly more cases of early non-small cell lung cancer (NSCLC) were caught following the introduction of low-dose CT screening recommendations nearly a decade ago, a quasi-experimental study found.

After the U.S. Preventive Services Task Force (USPSTF) in 2013 recommended low-dose CT for high-risk current and former smokers, the percentage of patients ages 55 to 80 presenting with stage I NSCLC increased by 3.9% (95% CI 3.0-4.8) annually over the next 4 years, reported Chi-Fu Jeffrey Yang, MD, of Massachusetts General Hospital in Boston, and colleagues.

Over the 3 years leading up to the new recommendations, the percentage of NSCLC cases among this age group that were stage I remained relatively stable (27.8% to 29.4%), but significantly increased from 2014 to 2018 (30.2% to 35.5%), the group wrote in The BMJ.

The odds that a patient would be diagnosed a full stage lower — e.g., stage I rather than II, or stage III rather than IV — versus the prior year also increased, from 2.3% annually in the years before the USPSTF recommendations to 8.7% in the years after.

Additionally, while median all-cause survival among NSCLC patients didn’t waver much from 2010 to 2013, a 4.1% annual change (16 to 18.3 months), median survival significantly increased by 11.9% per year from 2014 to 2018 (19.7 to 28.2 months).

The researchers calculated that due to a shift toward earlier stages of disease from 2014 to 2018, these improvements in survival averted an estimated 10,100 deaths.

“Although the adoption of lung cancer screening has been slow and screening rates have remained low nationally, the findings of this study indicate the beneficial effect that even a small amount of screening can have on lung cancer stage shifts and survival at the population level,” Yang’s group wrote.

While evidence of this stage shift is “compelling,” accompanying editorial authors Anne Melzer, MD, MS, of University of Minnesota in Minneapolis, and Matthew Triplette, MD, MPH, of the Fred Hutchinson Cancer Research Center in Seattle, pointed out that improved screening isn’t the only driving force behind this mortality benefit.

Instead, it likely reflects advances in cancer treatment that coincided with the introduction of screening, including the widespread use of mutational testing, targeted therapies, and immunotherapy, they wrote.

“Given the slow natural history of NSCLC, we would not expect the observed stage shift to result in such early mortality benefits,” added Melzer and Triplette. Though on a positive note, they pointed out these findings, “suggest that even poorly implemented screening can result in a stage shift that will almost certainly lead to downstream decreases in lung cancer mortality over the longer term.”

This retrospective analysis included 763,474 patients diagnosed with NSCLC from 2010 to 2018 in the National Cancer Database (ages 45 to 80) and the Surveillance, Epidemiology, and End Results database (ages 55 to 79).

Yang’s group also highlighted racial and ethnic disparities in the stage of NSCLC at diagnosis.

“In 2018, for the first time ever, stage I disease was the predominant stage of NSCLC identified among non-Hispanic white patients,” they noted. “By contrast, stage IV disease remained the predominant stage of NSCLC diagnosed among non-white patients.”

In addition, patients living in more educated and higher income areas were more likely to have stage I disease than stage IV disease at diagnosis, differences that “likely reflect disparities in access to screening” as well as the poor adoption of low-dose CT in the community setting, Yang’s group suggested.

Melzer and Triplette commented that as currently implemented, lung cancer screening will only further exacerbate these disparities.

“Researchers and policymakers must analyze not just how many people are being screened but also the ‘mismatch’ between who is screened and who bears the greatest burden of disease related to lung cancer,” the editorialists wrote. “Through such targeted interventions, screening can realize its full potential for everyone at high risk for lung cancer.”