Declining early-onset lung cancer mortality in Spain: Sex-specific trends and regional variations, 1999-2022.

Background: Lung cancer (LC) is the leading cause of cancer mortality globally, with a concerning increase in early-onset lung cancer (EO-LC), defined as cases diagnosed before age 50. This study investigates EO-LC mortality trends in Spain from 1999 to 2022, focusing on regional and gender disparities.

Methods: Data on LC mortality were obtained from the Spanish National Institute of Statistics, employing International Classification of Diseases codes for analysis. Joinpoint regression was utilized to estimate age-standardized mortality rates (ASMRs) and identify significant mortality trends across different Autonomous Communities (ACs).

Results: Total LC deaths in Spain increased; however, the proportion of EO-LC deaths significantly declined. In men, the proportion of EO-LC deaths decreased from 6.2 % to 1.6 %, while in women, it fell from 11.6 % to 3.3 %. The ASMR for EO-LC in men decreased from 8.4 per 100,000 to 1.6 per 100,000 (average annual percentage change (AAPC): -6.7 %). In women, ASMR rates fell from 1.7 per 100,000 to 1.2 per 100,000 (AAPC: -2.1 %). Notable regional declines were observed, particularly in Castile & León (-8.6 %) and Madrid (-8.2 %) for men. In contrast, female mortality trends were heterogeneous, with some regions exhibiting stable rates and others showing initial increases followed by significant declines.

Conclusions: While our findings indicate an overall improvement in EO-LC mortality rates-particularly among men-they also reveal ongoing regional and gender disparities that require targeted intervention. The strengths and limitations of this study emphasize the need for continued surveillance and further investigations into the determinants of EO-LC mortality.