“This analysis shows for the first time that nationwide mortality rates for the most common category of lung cancer, NSCLC, are declining faster than its incidence, an advance that correlates with the [FDA] approval of several targeted therapies for this cancer in recent years,” coauthor Douglas Lowy, MD, deputy director, National Cancer Institute, Bethesda, Md., said in a statement.
“Major improvements have been made in NSCLC treatment with the advent of targeted therapies and immunotherapies,” lead author Nadia Howlander, PhD, National Cancer Institute, and colleagues observed.
“The survival benefit for patients with NSCLC treated with targeted therapy has been shown in clinical trials, but our study highlights their possible effect at the population level,” they added.
In contrast, mortality from SCLC has dropped only in tandem with a decline in the incidence of SCLC, and survival has remained largely unchanged, the same analysis showed.
NSCLC is by far the most common type of lung cancer, accounting for more than 75% of all lung cancer cases in the United States. SCLC accounts for about 13%.
The study was published online Aug. 12 in the New England Journal of Medicine.
“Although overall mortality from lung cancer has been declining in the United States, little is known about mortality trends according to cancer subtype at the population level because death certificates do not record subtype information,” the authors commented.
“To address this data limitation, the U.S. Surveillance, Epidemiology and End Results (SEER) program has linked mortality records to incidence cancer cases,” the authors explained. This allowed them to calculate incidence-based mortality among men and women in the United States.
The incidence-based mortality method that the researchers used was applied to the SEER data to describe population-level mortality trends in the United States that were attributable to each subtype of lung cancer as well as gender from 2001 to 2016.
Among men, the incidence of NSCLC decreased gradually by 1.9% a year from 2001 to 2008, then more dramatically by 3.1% a year from 2008 to 2016.
Corresponding incidence-based mortality rates among men dropped by 3.2% a year from 2006 to 2013, then again more dramatically by 6.3% a year from 2013 to 2016.
“The 2-year relative survival among patients with lung cancer improved substantially from 26% among men with NSCLC diagnosed in 2001 to 35% among those with NSCLC diagnosed in 2014,” the researchers added.
Among women, the incidence of NSCLC remained unchanged between 2001 and 2006, after which it began to drop by 1.5% a year from 2006 to 2016.
“In contrast, incidence-based mortality decreased slowly [among women] by 2.3% annually ... from 2006 through 2014 and then at a faster rate of 5.9% annually ... from 2014 through 2016,” the authors noted.
The 2-year relative survival rate for patients with NSCLC was higher among women than among men, improving from 35% in 2001 to 44% in 2014.
Improvements in survival were also observed for all races and ethnicities, despite concerns that new cancer treatments might increase treatment disparities between races, because they are all so expensive, the authors commented.
Mortality from SCLC declined by 4.3% a year among men, but that decline was entirely due to a similar decrease in the incidence of SCLC. Survival at 2 years for patients with this subtype of lung cancer remained largely unchanged over the same interval.