Trends in thyroid cancer burden in Taiwan over two decades

Purpose: Thyroid cancer incidence has increased over recent decades with considerable geographic variations in incidence patterns. Here, we analyzed temporal trends in the incidence and mortality rates of thyroid cancer in Taiwan. Methods: We obtained age-standardized rates at a national level using data from the Taiwan Cancer Registry annual reports from 1995 to 2019. Trends in age-standardized rates were characterized by joinpoint regression analysis. Results: The age-standardized incidence rate of thyroid cancer increased from 3.00 per 100,000 person-years in 1995 to 15.46 per 100,000 person-years in 2019 (p < 0.001). Significant upward trends were observed in virtually all age groups, including adolescents and the geriatric population. The average annual percent changes were 7.97%, 2.60%, 2.77%, and 1.43% for papillary, follicular, medullary, and anaplastic thyroid cancers, respectively. The mortality rate from thyroid cancer decreased over time in women but remained stable in men. Conclusion: The incidence rates of thyroid cancer have steadily increased across gender, age groups, and tumor types over the past two decades. Future studies are needed to investigate potential etiological factors other than overdiagnosis that may drive these trends.