Incidence and mortality of thyroid cancer in 50 countries: a joinpoint regression analysis of global trends.

[PURPOSE] To evaluate the incidence and mortality trend of thyroid cancer, and compare its global incidence trends among different countries by age group and sex.

[METHODS] Data on age-standardized incidence and mortality rate of thyroid cancer among 50 countries were collected from the Cancer Incidence in Five Continents Volume XI; the Surveillance, Epidemiology, and End Results Program (SEER), the National Cancer Institute; the Nordic Cancer Registries (NORDCAN), and the WHO mortality database. The Average Annual Percent Change (AAPC) of the incidence and mortality trends was calculated by joinpoint regression analysis.

[RESULTS] The age-standardized incidence of thyroid cancer was 3.1 and 10.1 cases per 100,000 persons in men and women, respectively. The incidence of thyroid cancer increased in most countries among individuals irrespective of age groups, and increased in populations aged <40 years in several countries, including Korea (male: AAPC 25.3, 95% C.I. 22.3-28.4, p < 0.001; female: AAPC 18.5, 95% C.I. 16.2-20.9, p < 0.001), Poland (male: AAPC 19.1, 95% C.I. 1.4-39.7, p = 0.036; female: AAPC 13.7, 95% C.I. 7.6-20.2), and China (male: AAPC 18.6, 95% C.I. 12.1-25.5, p < 0.001; female: AAPC 13.3, 95%C.I. 11.5-15.1, p < 0.001).

[CONCLUSION] An increasing incidence of thyroid cancer was observed in younger subjects in a majority of countries, highlighting the need for more preventive strategies in this population and possible avoidance of over-diagnosis.