Global Patterns and Trends in Thymic Epithelial Tumor Incidence: Worldwide Health Care Disparity on Detection

Thymic epithelial tumors (TETs) are a group of rare thoracic malignancies with undefined global epidemiology. Comprehensive descriptions of prevalence features in TETs are informative in providing insight into the shifting epidemiologic patterns, problems with detection, and, therefore, better understanding and management of TETs.

Data were obtained from the Cancer Incidence in Five Continents database. Age-standardized incidence rate (ASR) and average annual percentage change (AAPC) were calculated by age, sex, region, country, and human development index (HDI) level.

Globally, the ASR of TETs was 0.26 per 100,000 in 2013-2017, with significant increases observed over 30 years (AAPC, 3.13). Most cases were diagnosed in people age 50-79 years, and males had a higher incidence than females. There were significant ethnic differences in incidence, with Asian and Pacific Islanders having the highest ASR, followed by Black people and White people. There were large disparities in the incidence both between and within countries, which were found to be associated with HDI. Very-high-HDI countries demonstrated a significantly higher ASR than low-HDI countries. In particular, the incidence of the same ethnicity was higher in countries with higher HDI. Most countries with high HDI had experienced a substantial increase in incidence, especially after 2003. However, the change was less pronounced in countries with relatively low HDI.

The observed variations in incidence are associated with HDI and are most likely attributed to disparities in disease detection. These findings highlight the need for greater attention to these rare malignancies and socioeconomic inequities in health care.