Trends in lung cancer incidence in Spain (1990-2019): insights from Global Burden of Diseases data.

Background: This study examines lung cancer incidence in Spain (1990-2019) through age-period-cohort (A-P-C) analysis and Global Burden of Diseases (GBD) data, unravelling the complex interplay of age, period, and birth cohort in shaping these trends.

Methods: Utilizing GBD and Spanish population data, the study calculates age-standardized incidence rates (ASIRs) and employs Joinpoint analysis to identify significant trends. A-P-C analysis dissects the individual effects of age, calendar period, and birth cohort on incidence patterns.

Results: Between 1990 and 2019, almost 738,000 cases of lung cancer were diagnosed in Spain, with an average annual increase of 1.7%. The ASIR of lung cancer in Spain from 1990 to 2019 showed a sustained upward trend in women (Average Annual Per cent Change: 2.5%, P < 0.05), reaching 23.3 cases per 100,000 in 2019, whilst men experienced a significant decrease in incidence rates (AAPC: -0.6%, P < 0.05), falling to 108.9 in 2019. The male-to-female incidence ratio decreased from 12.2 in 1992 to 4.9 in 2019. Joinpoint analysis identified distinct periods for both sexes, with men showing stability, decline and then a significant decrease, whereas women showed an initial increase followed by a decrease. The longitudinal age curves showed a consistently higher incidence risk in men, peaking in the 80-84 age group. Male cohorts since the 1920s showed a decreasing relative risk, whereas women showed fluctuations in risk over time.

Conclusion: Lung cancer rates are falling in Spain, especially amongst men, due to lower smoking rates. The gender gap is closing, but prevention targeted at women is needed. Tighter tobacco control and research into other risk factors are essential. Understanding the long-term effects of smoking and early exposure is key to better prevention and treatment in Spain.