Retinoblastoma as a Tracer of Curable Childhood Cancer: Mortality, Incidence and the Diagnosis-Outcome Gap at Ages 0–19 Years: A Systematic Analysis of the Global Burden of Disease Study 2023

Background: Retinoblastoma is the most common primary intraocular malignancy of childhood and is nearly universally curable where effective services exist: three-year survival is 99.5% in high-income countries versus 57.3% in low-income countries. Because its occurrence is largely non-modifiable while its outcome is highly treatment-dependent, retinoblastoma is among the most sensitive tracers of childhood cancer cure capacity. We quantified its global burden, trends, and diagnosis–outcome gap. Methods: We analysed Global Burden of Disease (GBD) Study 2023 estimates (results release v8352) for retinoblastoma (cause_id 1009). Deaths and incident cases at ages 0–19 years — the sum of the <5, 5–9, 10–14, and 15–19-year bands — were extracted for the global level, 21 regions, and five Socio-demographic Index (SDI) quintiles over 1990–2023, with a national map for 204 countries in 2022. The mortality-to-incidence ratio (M/I) served as a proxy for cure. Reporting follows GATHER. Results: In 2023, retinoblastoma caused 3,226 deaths (95% uncertainty interval [UI] 1,493–6,569) at ages 0–19 years, down 31.8% from 1990; the crude death rate declined significantly (estimated annual percentage change [EAPC] −1.48% per year, 95% CI −1.60 to −1.36), while the incident case count rose significantly (EAPC +0.63%, 95% CI 0.40 to 0.87). The global M/I fell from 87.4% to 55.5%, yet the low-to-high SDI M/I ratio widened from 3.1-fold to 13.0-fold — the widest disparity among 14 childhood cancers by point estimate (95% UI 3.02–39.65). Children under 5 years accounted for 87.7% of deaths (95% UI 67.1–96.1). The cross-SDI mortality gradient (18.8-fold) far exceeded the incidence gradient (1.5-fold). Conclusions: Residual retinoblastoma mortality is concentrated almost entirely in children under 5 years in low-SDI settings and is consistent with an outcome-driven divide rooted in diagnostic delay and treatment access. Community-level recognition of leukocoria offers the highest-leverage intervention, and the M/I provides a measurable indicator for monitoring the WHO Global Initiative for Childhood Cancer.