A study by researchers at the National Cancer Institute investigating mortality trends in lung cancer by subtype has found that population-level mortality from individuals with non–small cell lung cancer (NSCLC) fell sharply from 2013 to 2016, and that survival after diagnosis improved substantially. The study findings suggest that a reduction in incidence in conjunction with treatment advances likely explains the decline in mortality. The study by Howlader et al was published in The New England Journal of Medicine.
The two major histologic subtypes of lung cancer are non–small cell and small cell (SCLC), which account for 76% and 13%, respectively, of all cases of lung cancer in the United States. Although statistics from the American Cancer Society show that this year, about 228,820 people will be diagnosed with lung cancer, and approximately 135,720 will die from the disease, they do not specify how many of the deaths are from NSCLC and how many are due to SCLC. And although overall mortality has been declining in the United States, little is known about mortality trends by cancer subtype because death certificates do not record subtype information.
“Population-level mortality from NSCLC in the United States fell sharply from 2013 to 2016, and survival after diagnosis improved substantially. Our analysis suggests that a reduction in incidence along with treatment advances—particularly approvals for and use of targeted therapies—is likely to explain the reduction in mortality observed during this period.”— Howlader et al
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Study Methodology
The researchers analyzed data from the Surveillance, Epidemiology, and End Results (SEER) database to assess lung cancer mortality and linked deaths from lung cancer to incident cases in SEER cancer registries. The researchers used the data to evaluate population-level mortality trends from specific lung cancer subtypes. They also evaluated lung cancer incidence and survival according to cancer subtype, sex, and calendar year.
Joinpoint statistical software was used to assess changes in incidence and trends in incidence-based mortality.
Study Results
The researchers found that mortality from NSCLC decreased even faster than the incidence of this subtype, and that the decrease was associated with a substantial improvement in survival over time that corresponded to the timing of U.S. Food and Drug Administration approval of targeted therapy.
Among men, incidence-based mortality from NSCLC decreased 6.3% annually from 2013 through 2016, whereas the incidence decreased 3.1% annually from 2008 through 2016.
Corresponding lung cancer–specific survival improved from 26% among men with NSCLC that was diagnosed in 2001 to 35% among those in whom the cancer was diagnosed in 2014. This improvement in survival was found across all races and ethnic groups.
The study found similar patterns among women with NSCLC.
In contrast, mortality from SCLC declined almost entirely as a result of declining incidence, with no improvement in survival, which the researchers found correlates with limited treatment advances for SCLC in the time frame of the study.
“Population-level mortality from NSCLC in the United States fell sharply from 2013 to 2016, and survival after diagnosis improved substantially. Our analysis suggests that a reduction in incidence along with treatment advances—particularly approvals for and use of targeted therapies—is likely to explain the reduction in mortality observed during this period,” concluded the study authors.
Impact of Treatment on Lung Cancer Survival
“The survival benefit for patients with NSCLC treated with targeted therapies has been demonstrated in clinical trials, but this study highlights the impact of these treatments at the population level,” said Nadia Howlader, PhD, a mathematical statistician in the Division of Cancer Control and Population Sciences at the National Cancer Institute and lead author of this study, in a statement. “We can now see the impact of advances in lung cancer treatment on survival.”
Disclosure: For full disclosures of the study authors, visit nejm.org.
