Non-melanoma skin cancer burden in Spain: a nationwide analysis of incidence trends (1990-2019)

Non-melanoma skin cancer (NMSC) is the most -common skin cancer in Spain, yet national data on its incidence trends are limited. To analyse the trends in NMSC incidence in Spain from 1990 to 2019, examining variations by sex, age, period, and birth cohort. Data on NMSC incidence was sourced from the Global Health Data Exchange. Age-standardized incidence rates (ASIRs) were calculated using the direct method. Trends and average annual percentage changes were identified using Joinpoint regression analysis. Age-period-cohort analysis was applied to assess age-specific, period-specific, and cohort-specific relative risks. From 1990 to 2019, Spain reported 2,302,399 NMSC cases. ASIRs significantly declined post-2005, with men exhibiting slightly higher rates than women. Joinpoint analysis revealed distinct trends between genders, with men experiencing an initial rise followed by a decline, while women exhibited periods of increase interspersed with decline. APC analysis showed a net decrease in age-adjusted NMSC rates for both sexes. Local drift analysis showed a downward trend in most age groups, indicating a broad decrease at the population level. However, no decrease was observed in young men (20-24 years). Both sexes showed an increased risk of NMSC between 1990 and 2002, followed by a decrease. In particular, those born at the beginning of the 21st century showed a significant decrease in NMSC risk compared with earlier cohorts, suggesting a possible cohort effect. A comprehensive analysis of NMSC trends in Spain highlights the need for ongoing research and interventions to address the evolving burden.