In a new study, researchers found mortality rates from the most common lung cancer, non-small cell lung cancer (NSCLC), have fallen sharply in the United States in recent years, due primarily to recent advances in treatment.
The research was conducted by a team at the National Cancer Institute (NCI), part of the National Institutes of Health.
Reduced tobacco consumption in the U.S. has been associated with a progressive decrease in lung cancer deaths that started around 1990 in men and around 2000 in women.
Until now, however, scientists have not known whether newer treatments might contribute to some of the recent improvements.
This analysis shows for the first time that nationwide mortality rates for the most common category of lung cancer, non-small cell lung cancer, are declining faster than its incidence.
This is an advance that correlates with the [U.S. Food and Drug Administration] approval of several targeted therapies for this cancer in recent years.
In this study, researchers looked at data for both NSCLC, which accounts for 76% of lung cancer in the U.S. and small-cell lung cancer (SCLC), which accounts for 13%.
In the last decade, new treatments for NSCLC have become available, including those that target genetic changes seen in some NSCLC tumors as well as immune checkpoint inhibitors that help the immune system better attack NSCLC.
In contrast, there have been limited treatment advancements for SCLC.
The researchers were able to estimate lung cancer mortality trends for specific lung cancer subtypes.
The researchers found that, in recent years, deaths from NSCLC decreased even faster than the decrease in NSCLC incidence and the decrease in deaths was linked to an improvement in survival.
Among men, for example, deaths from NSCLC decreased 3.2% annually from 2006 to 2013 and 6.3% annually from 2013 to 2016, whereas incidence decreased 1.9% annually from 2001 to 2008 and 3.1% annually from 2008 to 2016.
Two-year survival for men with NSCLC improved over this time, from 26% for patients diagnosed in 2001 to 35% for those diagnosed in 2014. A similar improvement was observed for women.
In addition, improvements in two-year survival were seen for all races/ethnicities, despite concerns that the newer cancer treatments, many of which are expensive, might increase disparities.
The researchers had originally considered the possibility that lung cancer screening might help explain the decreases in NSCLC mortality, but their findings suggest that lung cancer screening rates, which remained low and stable, do not explain the mortality declines.
Instead, the rapid decline in deaths reflects both declines in incidence (due in large part to reductions in smoking) and improvement in treatment.
In contrast, the decrease in deaths from SCLC corresponded with the decrease in incidence, and two-year survival was largely unchanged.
Among men, for example, deaths declined 4.3% annually and incidence 3.6% annually. Findings were similar among women.
The reduced mortality from SCLC over time, therefore, primarily reflects declines in incidence—again, due largely to reduced smoking.
The team says the survival benefit for patients with non-small cell lung cancer treated with targeted therapies has been demonstrated in clinical trials, but this study highlights the impact of these treatments at the population level.
One author of the study is Douglas R. Lowy, M.D., NCI deputy director.
The study is published in the New England Journal of Medicine.
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