Drop in NSCLC Mortality Credited to Better Treatment

Improved treatment fueled a sharp decrease in mortality from the most common type of lung cancer in recent years, particularly among men, National Cancer Institute investigators reported.

Incidence-based mortality for non-small cell lung cancer (NSCLC) among men declined 3.1% annually from 2008 through 2016, but the rate of decline doubled to 6.3% annually from 2013 through 2016. A similar trend was observed in women, as incidence-based mortality declined 2.3% annually from 2006 through 2014 but accelerated to 5.9% annually from 2014 through 2016. The decreases were accompanied by significant improvement in 2-year survival for newly diagnosed, advanced NSCLC.

The decline in cancer-specific mortality exceeded a parallel decrease in NSCLC incidence, supporting the contribution of improved treatment to decreased mortality, as reported in the New England Journal of Medicine.

"The faster decreases in mortality from NSCLC as compared with the incidence of NSCLC are probably driven by improvements in survival, which in turn are potentially driven by dissemination of targeted therapies for NSCLC," Nadia Howlader, PhD, of the NCI Surveillance Research Program, and coauthors concluded. "These therapies were approved as first-line treatment for stage IV EGFR-positive NSCLC in 2013. 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."

Incidence trends for NSCLC and other lung cancer subtypes have been investigated and extensively reported, but less information has emerged regarding respective mortality trends. The advent of targeted agents and immunotherapy has dramatically improved treatment for NSCLC, which could contribute to population-level improvement in NSCLC-specific survival, the authors noted in the introduction to their findings.

Indirect support for the contributions of improved treatment came from the 2019 Annual Report to the Nation on the Status of Cancer, which showed a larger decrease in NSCLC mortality in the United States as compared with NSCLC incidence. The disparity was noted in both men and women.

Total lung cancer mortality has declined, as well, in men and women, but data derived from death certificates do not include cancer subtype. Data on subtype-specific trends provide insight into overall trends.

To address such limitations, Howlader and colleagues queried the NCI Surveillance, Epidemiology, and End Results (SEER) database, which links mortality records to incidence. The linkage facilitates calculation of "incidence-based mortality," which captures population-level mortality attributable to different tumor subtypes reported to SEER, the authors noted.

The analysis included SEER data from 2001 (the first year NSCLC was reliably identified) through 2016. Results showed that NSCLC incidence among men decreased by 1.9% annually from 2001 through 2008, then declined by 3.1% annually through 2016. The decline in incidence-based mortality significantly exceeded the incidence decline during the early part of the study period (3.2% annually, 95% CI 2.5%-4.0%, vs 1.9%, 95% CI 1.6%-2.2%) and at the end (6.3%, 95% CI 3.4%-9.0%, vs 3.1%, 95% CI 2.8%-3.3%).

For women, incidence-based mortality declined by 2.3% annually from 2006 through 2014, accelerating to 5.9% per annum from 2014 through 2016. In contrast, incidence rose by 0.5% annually from 2001 to 2006 before declining by 1.5% annually from 2006 through 2016.

"The faster decreases in lung-cancer incidence among men than among women can be attributed to the relative differences in smoking prevalence according to sex," the authors stated.

Two-year cancer-specific survival for men improved from 26% in 2001 to 35% in 2016 and from 35% to 44% in women over the same time period.

Separate analyses for small-cell lung cancer (SCLC) showed similar decreases in both incidence and incidence-based mortality, indicating "that the decrease in SCLC mortality can be explained entirely by a decrease in incidence," Howlader's group reported. Two-year SCLC survival for men did not change over the study period (12% in 2001, 11% in 2016) while improving slightly among women (14% vs 17%).

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