# The International Neuroblastoma Risk Group (INRG) classification system

Source: https://onco.cc/key-papers/paper-inrg-cohn-jco-2009/  
OnCo record `paper-inrg-cohn-jco-2009` (Key paper). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Analysing 8,800 patients worldwide, the INRG task force built a pretreatment classification for neuroblastoma using stage, age, histology, MYCN, chromosome 11q and ploidy that sorts children into very low, low, intermediate and high-risk groups.

## Summary

Analysis of 8,800 children with neuroblastoma diagnosed between 1990 and 2002 from international cooperative groups, defining sixteen pretreatment groups by INRG stage, age, histological category, grade of differentiation, MYCN status, 11q aberration and ploidy, assigned to four risk groups by five-year event-free survival.

## Fields

- Kind: Key paper
- Last checked: 2026-09-17
- Journal: Journal of Clinical Oncology
- Year: 2009
- DOI: 10.1200/JCO.2008.16.6785
- Authors: Cohn SL, Pearson AD, London WB, et al.
- Findings: Sixteen pretreatment groups collapsed into very low (over 85 percent event-free survival), low, intermediate and high risk (under 50 percent).
- What it means: Every neuroblastoma risk group on this site (very low, low, intermediate, high) is defined by the INRG system, which allows trials across continents to be compared.
- Caveats: Based on patients treated in the 1990s; contemporary outcomes are better in most groups.; Segmental chromosome aberrations beyond 11q are being incorporated in revisions.

## Sources

- J Clin Oncol 2009: https://doi.org/10.1200/JCO.2008.16.6785
- PubMed: https://pubmed.ncbi.nlm.nih.gov/19047291/

## Connected records

- cancers: [High-risk neuroblastoma](https://onco.cc/cancers/neuroblastoma-high-risk/), [Intermediate-risk neuroblastoma](https://onco.cc/cancers/neuroblastoma-intermediate-risk/), [Low-risk neuroblastoma (INRG very low and low risk, including stage MS)](https://onco.cc/cancers/neuroblastoma-low-risk/)
- journals: [Journal of Clinical Oncology](https://onco.cc/journals/jco/)

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