1. In this retrospective cohort study, there was an observed decrease in mortality in non-small-cell lung cancer patients that corresponded with the approval of targeted therapies
2. The improved mortality of small cell lung cancer was not driven by treatment advancement but rather a decrease in the incidence
Evidence Rating Level: 2 (Good)
Study Rundown: Lung cancer is the deadliest cancer in the United States. It can be divided into two histological subtypes: non-small-cell lung cancer (NSCLC) and small-cell lung cancer (SCLC). Using the U.S. Surveillance, Epidemiology, and End Results (SEER) database, the authors in this study analyzed mortality trends attributed to the specific histological subtype of lung cancer termed incidence-based mortality. For men and women with NSCLC, incidence and incidence-based mortality decreased, with a greater mortality decrease from 2013-2016 corresponding with an improvement in survival from diagnosis. For SCLC, incidence and incidence-based mortality decreased but with no improvement in survival from diagnosis. Notably, the authors point out that EGFR targeted therapies were approved in 2013 which corresponds to the increase in survival in NSCLC. There should be caution in the interpretation in the study’s suggestion that the survival benefit is entirely driven by targeted therapies as there is no direct data on the number of patients treated with EGFR targeted therapies right after 2013. However, the results of these study are generalizable given that it encompassed diverse demographics which showed consistent trends across race and gender subgroups and adequate follow-up data.
Relevant Reading: Updated statistics of lung and bronchus cancer in United States (2018)
In-Depth [retrospective cohort]: In this retrospective cohort study, lung cancer incidence and lung cancer linked deaths were analyzed in the SEER cancer registry from 2001 to 2016. For NSCLC, in men, the annual incidence decreased by 1.9% from 2001 to 2008, and then by 3.1% from 2008 to 2016. Incidence-based mortality decreased by 3.2% annually from 2006 to 2013 and then decreased by 6.3% from 2013 to 2016. Among women, 2001-2006 incidence did not change significantly, while from 2006-2013 incidence decreased by 1.5% annually. Incidence-based mortality decreased by 2.3% from 2006 to 2014, and then by 5.9% from 2014-2016. 2-year survival improved from 35% in 2001 to 44% in 2014 for women and went from 25% to 35% for men. For SCLC from 2001-2016, in men, the incidence decreased by 3.6%, while incidence-based mortality decreased by 4.3%. For women, the incidence decreased by 2.7% and incidence-based mortality decreased by 3.7%. 2-year survival from 2001 vs. 2016 was 12% and 11% for men and 14% and 17% for women. Taken together, these results indicated that mortality decreases in NSCLC were likely driven by improved survival, and for SCLC, it was mainly driven by decreased incidence.
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