Sex- and Region-Specific Incidence and Mortality Trends in Laryngeal and Oropharyngeal Cancer: A 95,000-Case Population-Based Registry Analysis from Poland, 1999–2023

Background: Head and neck cancers show marked regional and sex-specific heterogeneity, but long-term trends in laryngeal cancer (LC) and oropharyngeal cancer (OPC), particularly in relation to industrialized environments, remain insufficiently characterized. Methods: This population-based time-trend study analysed 95,423 LC and OPC cases’ (59,160 LC; 36,263 OPC) incidence and mortality data from the Polish National Cancer Registry (PNCR, 1 January 1999 to 31 December 2023). Age-standardized incidence and mortality rates were analysed using log-linear regression with tests for parallelism and intersection, and multivariable models including year, sex and region. Results: In men, LC incidence and mortality declined significantly over time regions, whereas OPC incidence and mortality increased significantly. In women, LC incidence declined modestly, with less consistent mortality change, while OPC incidence and mortality increased steeply in both regions. For both sexes, the slopes of LC and OPC incidence and mortality trends differed significantly, and the corresponding curves crossed during the study period, indicating a shift in disease burden from LC to OPC. Across multiple comparisons, trends in the highly industrialized region and the rest of Poland were often parallel but vertically separated, with less favourable levels in the industrialized region. In multivariable models (R2 > 0.90 for all), calendar year and male sex were independently associated with declining LC and rising OPC patterns, while residence in the highly industrialized region was associated with higher LC mortality and higher OPC incidence. Conclusions: Over 25 years, LC declined while OPC rose sharply, particularly among women. Regional differences were also observed, with a higher burden of selected outcomes in the highly industrialized region; however, these ecological associations should not be interpreted as evidence of a causal effect of industrialization or air pollution.