Incidence of early-onset solid cancers in Hungary in the first two decades of the 21 st century based on a population-based registry

Background: Newly discovered malignancies at a relatively younger age (<50) are of great scientific interest. Previous studies found that the incidence of these early-onset cancers showed a global increase, although the pattern varied by cancer type. However, analysis of the Hungarian data has not yet been published. Methods: The Hungarian National Cancer Registry (HNCR) is responsible for data collection of the Hungarian cancer patients. Its operation is population-based in accordance with international standards and covers the entire country. Based on the 10 th Revision of International Statistical Classification of Diseases and Related Health Problems, newly discovered cancer cases were extracted from the HNCR's database. The query focused on patients between the ages of 20 and 49 and period from 2001 to 2019. Next to absolute case numbers, age-standardized values were also analyzed (reference: European Standard Population 2013). Spearman's correlation test was performed to identify gender- and disease-specific trends. Results: During the studied period, the incidence of early-onset cancers showed decrease among males, while it did not change among females. It should be noted that compared to the total number of newly discovered cancer cases, the proportion of early-onset cancers showed decreasing trend in both genders. Categorization by cancer type revealed that among younger age the incidence of female breast and uterine corpus cancer elevated, while cervical cancer showed a decrease - the latter trend exceeded that of the general population. The incidence of colorectal cancer did not change among females, but decreased among males. The incidence of tobacco-related lung cancer and head and neck region decreased. Conclusion: Compared to analyses enrolled global trends, the Hungarian situation of early-onset cancers seemed to be more complex. On one hand, activities in the past few years such as introduction of HPV vaccination and restrictions on smoking resulted a decrease in the number of related cancers. On the other hand, new mechanisms underlying the increasing types of cancers (e.g. breast cancer) need to be identified.