# Spanish Paediatric Haematology and Oncology Survival Results and Trends, 1999–2022

## TL;DR

This study analyzes childhood cancer survival trends in Spain from 1999 to 2022, showing significant improvements in survival rates for several cancer types.

## Contribution

The study provides up-to-date survival estimates using the period approach and identifies specific tumor types with notable survival improvements.

## Key findings

- 5-year overall survival in Spain increased from 75.4% to 84.6% between 1999–2003 and 2019–2022.
- Ependymomas showed the fastest annual improvement in survival (1.51 points annually).
- Survival rates for haematological malignancies and rhabdomyosarcomas improved significantly.

## Abstract

Childhood cancer survival is a key indicator for evaluating therapeutic efficacy and the functioning of health care systems. This study uses data from 20,534 childhood cancer cases (0–14 years) treated at Spanish paediatric haematology and oncology units from 1999 to 2021. We report retrospective nationwide survival results for major diagnostic groups and clinically relevant subtypes. To provide the most up-to-date picture, we used the period approach to estimate survival for recent years (2019–2022), which predicts the outcomes that will eventually be observed once follow-up is complete. We analysed survival trends to evaluate progress for each tumour, identifying potential change points. Our findings show that 5-year overall survival in Spain for the period 2019–2022 was 84.6%, with notable improvements in haematological malignancies, ependymomas, medulloblastomas, neuroblastomas, and rhabdomyosarcomas. These results aim to maximise comparability across registries and provide essential benchmarks for clinicians, researchers, and policymakers.

Background: 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. Methods: 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 using joinpoint Cox models for 1999–2022. Results: For all tumours combined, 5-year OS increased from 75.4% to 84.6% between 1999–2003 and 2019–2022. While positive trends were identified for all haematological malignancies examined, a more varied scenario was evident for solid tumours, as ependymomas improved fastest (1.51 points annually), and sarcomas, except for rhabdomyosarcoma, remained stagnant. Conclusions: Our results reflect a period characterised by a combination of new therapeutic developments, improved diagnostics, and more refined risk stratification, which has ultimately led to a reduction in disease-related mortality.