Patterns of Childhood Cancer Mortality in Hungary Since the Turn of the Millennium, Including the Two Years of the COVID-19 Pandemic

<b>Objectives</b>: We aimed to analyse the pattern of childhood cancer mortality among children under 15 years in Hungary between 2001 and 2021. In addition, annual and cyclical trends were examined. <b>Methods</b>: The number of deaths was obtained from the nationwide population register over the study period by gender, age group, and region for each year. Data were analysed using the Poisson regression method and cyclic trends were investigated using the Walter-Elwood method. <b>Results</b>: Overall, 14,931 childhood deaths (1092 from cancers) were registered between 2001 and 2021. The cancer mortality risk was significantly higher among boys than girls. A significantly decreasing trend was detected for yearly childhood cancer mortality rates, with an annual IRR of 0.976 (95% CI: 0.966-0.986; <i>p</i> < 0.001). This tendency was not influenced by the pandemic. However, different patterns of seasonal variation were revealed in childhood cancer mortality rates during 2020-2021 and 2001-2019. <b>Conclusions</b>: The annual trend in childhood cancer mortality was not affected by the coronavirus pandemic. However, there was a different pattern of childhood cancer mortality during the pandemic and non-pandemic period in Hungary. Considering the seasonal variation in monthly childhood cancer mortality rates, we hypothesized that environmental factors might play an important role in the aetiology of childhood cancer deaths.