Emerging Trends in the Incidence (1999–2022) and Mortality (1999–2023) of Thyroid Cancer in the United States: CDC WONDER Database Study

Background: Thyroid cancer (TC) is a common endocrine malignancy with a rising global incidence. This study examined trends in TC incidence and mortality in the United States over the past two decades. Methods: TC mortality data from 1999-2023 and incidence data from 1999-2022 were obtained from Centers for Disease Control and Prevention Wide-ranging Online Data for Epidemiologic Research. Age-adjusted incidence rates (AAIRs) and age-adjusted mortality rates (AAMRs) per 100,000 person-years were standardized to the 2000 United States standard population. Temporal trends were analyzed using the Joinpoint Regression Program to calculate annual percent changes (APCs) and average annual percent changes (AAPCs) with 95% confidence intervals. Analyses were stratified by sex, age, race, and census region. A sensitivity analysis restricted to 1999-2019 was also conducted. Results: Overall, 933,521 TC cases and 43,071 TC-related deaths were identified, with an AAIR of 12.12 and an AAMR of 0.49. Incidence rose markedly from 1999 to 2009 (APC=7.25%), stabilized during 2009-2014, and declined from 2014 to 2022 (APC=-2.42%), especially among females. In males, incidence increased until 2011 and then declined slightly. Mortality increased modestly overall (AAPC=0.30%), mainly among males and adults aged ≥75 years. The Northeast had the highest AAIR (15.73), whereas the West had the highest AAMR (0.55). Non-Hispanic Whites had increasing mortality, while non-Hispanic Blacks had the lowest incidence. Conclusion: In the United States, TC incidence shifted from increase to decline, coinciding with growing awareness of potential overdiagnosis. In contrast, mortality continued to show a modest upward trend, underscoring the importance of ongoing surveillance and focused attention to high-risk populations.