e20536 Background: Lung cancer population mortality has decreased over the last decade. Smoking cessation, medical therapies, CT screening, and earlier therapeutic interventions may all contribute to this decrease. We investigate the role of stage shift on population mortality of non-small cell lung cancer (NSCLC). Methods: Data from Surveillance, Epidemiology, and End Results (SEER) were queried to assess all patients from 2006-2016 with microscopically confirmed NSCLC. Incidence based mortality was evaluated by year of diagnosis. In order to assess shifts in diagnostic characteristics, stage and histology distributions were examined by year using χ2 tests. Trends were assessed by using the average annual percentage change (AAPC), calculated with JoinPoint software. Kaplan-Meier survival analysis was also performed to assess overall survival according to stage and to compare those missing any stage to those with a reported stage. Results: Between 2006-2016, 312,382 patients in SEER were diagnosed with NSCLC. Incidence based mortality within 5 years of diagnosis for NSCLC has significantly decreased over the last decade (AAPC -3.7 (95% confidence interval (CI): -4.1 - -3.4)). When assessing stage shift, there was a significant association between year of diagnosis and stage (p < 0.0001), with the percent in each year diagnosed at stage I/II increasing from 26.5% to 31.2% from 2006-2016, corresponding to a statistically significant AAPC of 1.5 (95% CI: 0.5-2.5); the percent diagnosed at stage III/IV decreased significantly from 70.8% to 66.1% (AAPC: -0.6 (95% CI: -1.0 - -0.2)). The percent missing staging information was relatively stable in this timeframe and not significant (AAPC: -1.6 (-7.4 - 4.5)). Year of diagnosis was significantly associated with tumor histology (p < 0.0001). There was a statistically significant increase in the percent of those diagnosed with adenocarcinomas, from 42.9% in 2006 to 59.0% in 2016 (AAPC: 3.4 (95% CI: 2.9-3.9)). Median survival for those with stage I/II was 57 (interquartile range (IQR): 18- - ) months; for stage III/IV was 7 (IQR: 2-19) months; and for those missing stage was 10 (IQR: 2-28) months. Patients with stage I/II had significantly better survival compared to those diagnosed with stage III/IV, or missing stage (p < 0.0001). Conclusions: Population-level mortality for NSCLC has decreased from 2006-2016. While advances in treatments, particularly targeted therapeutics have played a role in affecting mortality, our analysis suggests that decreased mortality is also due to a diagnostic shift from later to earlier stage lung cancer. Studies investigating the effectiveness of treatment on lung cancer mortality must take into account the confounding effect of stage shift on survival and mortality outcome.
Association of Stage Shift and Population Mortality Among Patients With Non–Small Cell Lung Cancer
