Background: The past four decades have seen a steady increase in thyroid cancer in the United States (US). This study investigated the impact of the American Thyroid Association (ATA)'s revised cancer management guidelines on thyroid cancer incidence trends and how the trends varied by socioeconomic, histologic, geographic, and racial and ethnic characteristics from 2000 to 2020. Methods: We used data from the Surveillance, Epidemiology, and End Results (SEER) database to identify thyroid cancer cases diagnosed among US patients between 2000 and 2020. We employed joinpoint regression software to fit, assess, and compare thyroid cancer incidence trends over time stratified by socioeconomic status (SES), histologic type, geographic location, and race/ethnicity. Results: Between 2000 and 2009, there was an average annual increase of 5.8% in thyroid cancer incidence (average annual percent change (AAPC): 5.8, p < 0.05). Subsequently, there was a modest rise (AAPC: 1.1, p < 0.05) from 2010 to 2015, followed by a significant annual decrease of 4.8% from 2016 to 2020 (AAPC: -4.8, p < 0.05). The joinpoint regression models identified prominent inflection points around 2009 and 2015, aligning with the years of the ATA's cancer management revisions. These intricate dynamics in thyroid cancer incidence trends from 2000 to 2020 were shaped by SES and histologic, geographic, and racial/ethnic factors. Conclusions: Thyroid cancer incidence trends over the past two decades can be partially explained by the changes in thyroid cancer screening and management recommendations. These findings underscore the importance of cancer management strategies and highlight the need for targeted interventions to address disparities in thyroid cancer incidence across minority demographic groups.
Keywords: incidence; racial disparities; sociodemographic; thyroid cancer; trends.