biostudies-literatureUnknown18(3)Alfonso-Comos P<b>Background</b>: Childhood cancer is the leading cause of natural death among children in high-income countries, despite treatment improvements. The Spanish Registry of Childhood Tumours (RETI-SEHOP) systematically records all cases treated within the network of SEHOP units. Using RETI-SEHOP data, we evaluated survival trends to assess progress in patient care, both overall and by tumour. <b>Methods</b>: A total of 20,534 childhood cancer cases (0-14 years) were recorded across the period 1999-2021. The 1-, 3-, and 5-year overall survival (OS) were estimated using the Kaplan-Meier method, applying the cohort approach for 1999-2018 and the period approach for 2019-2022. OS by age and sex was analysed in the recent 2009-2018 incidence cohort. Age-adjusted OS time trends were examined usingCancers362https://www.ebi.ac.uk/biostudies/studies/S-EPMC12897301biostudies-literatureSpanish Paediatric Haematology and Oncology Survival Results and Trends, 1999-2022.PMC12897301Canete AReti-Sehop Survival Working GroupVerdu-Amoros JFernandez Navarro JMBriz-Redon ARives SAlfonso-Comos PDapena Diaz JLfalseSpanish Paediatric Haematology and Oncology Survival Results and Trends, 1999-2022.<b>Background</b>: Childhood cancer is the leading cause of natural death among children in high-income countries, despite treatment improvements. The Spanish Registry of Childhood Tumours (RETI-SEHOP) systematically records all cases treated within the network of SEHOP units. Using RETI-SEHOP data, we evaluated survival trends to assess progress in patient care, both overall and by tumour. <b>Methods</b>: A total of 20,534 childhood cancer cases (0-14 years) were recorded across the period 1999-2021. The 1-, 3-, and 5-year overall survival (OS) were estimated using the Kaplan-Meier method, applying the cohort approach for 1999-2018 and the period approach for 2019-2022. OS by age and sex was analysed in the recent 2009-2018 incidence cohort. Age-adjusted OS time trends were examined using2026-01-01T00:00:00Z2026 Jan2026-07-08T03:15:30.505Z2026-07-08T03:08:39.266ZS-EPMC128973014168183510.3390/cancers18030362