# Survival outcomes and relapse patterns in high-risk metastatic neuroblastoma treated with radiotherapy-only consolidation in a resource-limited setting: a retrospective study from a lower-middle-income country

## TL;DR

This study examines the effectiveness of radiotherapy-only treatment for high-risk metastatic neuroblastoma in a low-resource setting, finding limited success and highlighting the need for better access to advanced therapies.

## Contribution

The study provides real-world evidence on treatment outcomes for high-risk neuroblastoma in a lower-middle-income country, emphasizing the limitations of radiotherapy-only consolidation.

## Key findings

- Radiotherapy-only consolidation after chemotherapy resulted in a median overall survival of 20.1 months.
- Relapses occurred in 84% of patients, most commonly at new anatomical sites.
- No significant differences in survival were found based on radiotherapy dose or baseline characteristics.

## Abstract

High-risk metastatic neuroblastoma (HR-MNB) requires intensive multimodal therapy for durable remission. In many low- and middle-income countries (LMICs), access to autologous stem cell transplantation (ASCT) and maintenance immunotherapy remains limited. This study evaluated survival outcomes and relapse patterns among patients with HR-MNB treated with radiotherapy-only consolidation after achieving a complete or near-complete response to induction chemotherapy in Iraq.

We conducted a retrospective cohort study of children with HR-MNB treated between December 2023 and March 2024 at a national radiotherapy center. Eligible patients received standard induction chemotherapy and consolidation radiotherapy with curative intent, without ASCT. Relapse-free survival (RFS) and overall survival (OS) were estimated using Kaplan–Meier methods. Relapse patterns were classified as local, distant, new-site, or combined failures. Subgroup analyses examined associations between survival outcomes and radiotherapy dose, age, and metastasis sites.

Twenty-five patients (median age, 48 months) were included. The median RFS from diagnosis was 18 months (95% confidence interval (CI), 14.4–21.6), and the median OS was 20.1 months (95% CI, 16.2–23.9). From radiotherapy initiation, the median RFS and OS were 5.8 and 11.4 months, respectively. Relapse occurred in 84% of patients, most frequently at new anatomical sites (56%). Subgroup analyses revealed no significant differences in survival based on radiotherapy dose or baseline characteristics.

Radiotherapy-only consolidation following induction chemotherapy provided limited systemic disease control, reflected in early relapses and modest survival. These findings highlight the urgent need to expand access to ASCT, immunotherapy, and integrated care pathways to improve outcomes for HR-MNB in LMICs. Reporting real-world data from resource-constrained settings contributes essential evidence to guide equitable neuroblastoma treatment strategies globally.