Retinoblastoma Incidence in Saudi Arabia: A 20-Year Analysis.

BACKGROUND: Retinoblastoma (Rb) represents the most frequent primary intraocular cancer in the pediatric population; yet comprehensive national data are limited in Saudi Arabia due to incomplete cancer registry coverage and underreporting. The present study systematically investigates the incidence, distribution, and trends of retinoblastoma across Saudi Arabia over two decades, utilizing robust data from the Saudi National Cancer Registry (SCR), a nationwide surveillance system overseen by the Ministry of Health. METHODS: This retrospective population-based analysis included all children diagnosed with Rb in Saudi Arabia between January 1, 2000, and December 31, 2019. The study examined incidence rates and temporal patterns by age, regional location, and tumor histology. RESULTS: Out of 542 documented cases (258 females, 284 males), the age-standardized incidence rate (ASIR) for children aged 0-4 years demonstrated an initial increase, peaking at 1.26 per 100,000 in 2003, followed by a gradual decline to 0.93 per 100,000 by 2019. Higher incidence rates were detected in major urban centers, especially Riyadh and Makkah, likely reflecting demographic density, enhanced diagnostic practices, and more accessible specialized care. Most tumors were either undifferentiated (Grade IV) or not otherwise specified (NOS, 63%), while diffuse retinoblastoma was rare (2%). Diagnosis was predominantly confirmed by histopathological evaluation (88.3%). CONCLUSION: This study offers the most comprehensive picture to date of retinoblastoma incidence and patterns in Saudi Arabia. The observed rising incidence, together with regional disparities, emphasizes the need for more refined cancer surveillance, equitable resource allocation, and accelerated early detection strategies, particularly in underserved areas. These findings provide essential baseline metrics to inform national cancer control policies and optimize equitable resource distribution.