Incidence Trends in Head and Neck Cancer Subsites: A National Population-Based Study (2001-2020)

Objectives This descriptive epidemiological study aims to investigate trends in head and neck cancer (HNC) within the anatomical divisions of laryngeal, oropharyngeal, and oral cavity cancers over the past two decades. Design Retrospective population-based observational study. Setting Scotland, a constituent country of the United Kingdom, with a population of 5.5 million. Participants Newly diagnosed HNC patients in Scotland registered in the Scottish Cancer Registry from 2001 to 2020. Main Outcome Measures Trends in age-standardised incidence rates from 2001 to 2020 for each HNC subsite, anatomical division, and individual sociodemographic using joinpoint regression analysis and Poisson regression analysis. Results Overall, HNC incidence rates have remained stable, with an average annual percentage change (AAPC) of 0.29% (p = 0.34). However, oropharyngeal cancer showed a significant increase in incidence rates with an AAPC of 3.76% (p < 0.001); the tonsils (C09) and the base of the tongue (C01) experienced the greatest increases in AAPC of 4.63% (p = 0.001) and 4.79% (p < 0.001), respectively. Conversely, laryngeal cancer rates declined significantly, with an AAPC of -2.56% (p < 0.001). This decline was primarily influenced by annual reductions of -2.40% (p = 0.09) in cancers affecting the glottis (C32.0). Incidence rates for oral cavity cancer remained mostly stable, with an AAPC of -0.60% (p = 0.08). Conclusion This analysis highlights that behind a stable HNC incidence rate over the past 20 years, there are differential trends among various anatomical divisions with an overall increasing burden of oropharyngeal cancer and declining rates of laryngeal cancer.