# International Classification of Retinoblastoma (groups A to E)

Source: https://onco.cc/terms/retinoblastoma-classification/  
OnCo record `retinoblastoma-classification` (Term). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Retinoblastoma inside the eye is graded from group A (small tumours away from the centre of vision) to group E (eyes with features that make saving the eye unlikely), and the group guides whether the eye can be saved.

## Summary

The NCI Thesaurus describes the classification as grouping intraocular retinoblastoma by tumour size and location, the extent of fluid under the retina, and seeding into the retina or vitreous. In the NCI's health professional summary: group A, small tumours within the retina away from the foveola and optic disc; B, all other discrete tumours confined to the retina; C, discrete local disease with minimal seeding; D, diffuse disease with significant seeding; E, one or more poor-prognosis features, such as tumour touching the lens. The NCI notes published versions of the definitions contain inconsistencies. Outcomes of intra-arterial chemotherapy track the group, with eye salvage below 60% for group D in one series and above 80% in specialised centres.

## Fields

- Kind: Term
- Last checked: 2026-11-04
- Also known as: International Classification of Retinoblastoma; ICRB; IIRC; International Intraocular Retinoblastoma Classification; retinoblastoma group

## Sources

- National Cancer Institute, Retinoblastoma treatment (PDQ), health professional version: https://www.cancer.gov/types/retinoblastoma/hp/retinoblastoma-treatment-pdq
- NCI Thesaurus C189851, International Intraocular Retinoblastoma Classification: https://evsexplore.semantics.cancer.gov/evsexplore/concept/ncit/C189851

## Connected records

- terms: [Disease-specific staging and risk systems (FIGO, Ann Arbor, IPI, R-ISS, ELN, IMDC)](https://onco.cc/terms/staging-systems/)
- cancers: [Retinoblastoma](https://onco.cc/cancers/retinoblastoma/)

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