The Pandemic Fault Line: Rising Childhood and Adolescent Cancer Mortality in 2020–2021 and the Widening Global Survival Divide, 1990–2023 — A Systematic Analysis of the Global Burden of Disease Study 2023

Background: Childhood and adolescent cancer mortality has declined for three decades, yet whether the COVID-19 pandemic interrupted this decline has never been quantified at the population level; the official Global Burden of Disease (GBD) 2023 childhood cancer analysis does not examine the 2019–2021 window. We analyzed the 0–19-year neoplasm burden in GBD 2023 with explicit attention to the pandemic window.Methods: We extracted deaths and incident cases for the GBD Level-2 cause “Neoplasms”—an envelope of malignant, benign and in-situ tumors—at ages 0–19 years, both sexes, 1990–2023, globally, for 21 regions and five Socio-demographic Index (SDI) quintiles. We computed crude rates on back-calculated populations, long-term estimated annual percentage changes (EAPCs), and pandemic-window changes with Monte Carlo-propagated uncertainty intervals (UIs); a mortality-to-incidence (M/I) ratio served as a comparative detection-and-survival proxy. Same-pipeline pediatric tuberculosis and lower respiratory infection series provided internal controls. Because approximately 96% of incident cases are benign or in-situ tumors, incidence-side and M/I absolute values are interpreted comparatively only; all primary inference is mortality-based.Results: In 2023, neoplasms caused 148,436 deaths (95% UI 139,201–157,671) at ages 0–19 years, 26.6% fewer than in 1990—versus 144,000 (131,000–162,000) in the official malignant-only analysis, whose intervals fully overlap ours. Reversing three decades of decline, deaths rose 4.7% (−3.3 to +13.5) between 2019 and 2021 to 152,553, the highest since 2008; the rise was broadly graded by development (high-SDI −2.1% to low-SDI +7.9%) and had not fully receded by 2023. Mortality declined slowest among comparator diseases (EAPC −1.61 versus tuberculosis −3.96 and lower respiratory infections −3.89); the neoplasm-to-tuberculosis death ratio crossed over from 0.78 to 1.69. The low-to-high-SDI M/I gap widened from 14.5-fold to 21.7-fold. Adolescents aged 15–19 years became the largest mortality band among ages 5–19 years—nearly level with the under-5 band (41,182 versus 42,222 deaths)—and rose most of any band over 2019–2023 (+8.0%), while under-5 deaths fell 6.3%. Interrupted time series analysis formally confirmed the mortality reversal: at the BIC-optimal intervention year of 2019, the global mortality series showed an immediate level increase of 7.5% (95% CI 2.4 to 12.9), with 2023 mortality 15.8% (10.7 to 21.2) above the counterfactual pre-pandemic trend.Interpretation: The pandemic window marks a fault line in pediatric cancer control: a development-graded mortality reversal superimposed on a widening survival divide. Because GBD 2023 mortality models incorporate pandemic-period covariates, we present this as a data-and-model signal requiring triangulation, not a pure causal claim. Reaching the WHO childhood cancer survival targets requires closing the diagnostic-treatment gap the pandemic exposed.