International testicular cancer incidence rates in children, adolescents and young adults

Background: Testicular cancer is the most common cancer in young men in developed countries. In adults, international variation in testicular cancer incidence rates has been well-described, while previous research on pediatric and adolescent testicular cancer has been more geographically limited. Methods: In this analysis, we used data from the three most recent volumes of Cancer Incidence in Five Continents (CI5) and the National Cancer Institute's SEER 18 registries to compare incidence rates for testicular cancer in children (ages 0–14) and adolescents and young adults (AYA; ages 15–39). Results: We find that geographic incidence patterns in AYA are different from patterns in children under 15. In AYA, incidence is highest in Europe (137.4 per million), followed by Oceania (116.9 per million), North America (94.9 per million), South and Central America (66.5 per million), and lowest in Asia (27.1 per million). In contrast, childhood incidence is highest in Asia (4.2 per million) and South America (5.0 per million) and lowest in Europe (2.1 per million) and North America (2.5 per million). In the United States, patterns in incidence rates in racial and ethnic groups mirror international rates. Conclusion: These differences in incidence rate variations in pediatric and AYA testicular cancer are intriguing and may aid in understanding the different etiologies of testicular cancer by age group.