Although there are several staging systems available for retinoblastoma, for the purpose of treatment, retinoblastoma is categorized into intraocular and extraocular disease.Intraocular
Intraocular retinoblastoma is localized to the eye and may be confined to the retina or may extend to involve other structures such as the choroid, ciliary body, anterior chamber, and optic nerve head. Intraocular retinoblastoma, however, does not extend beyond the eye into the tissues around the eye or to other parts of the body.Extraocular
Extraocular (metastatic) retinoblastoma has extended beyond the eye. It may be confined to the tissues around the eye (orbital retinoblastoma), or it may have spread to the central nervous system, bone marrow, or lymph nodes (metastatic retinoblastoma).Reese-Ellsworth Classification for Intraocular Tumors
Reese and Ellsworth developed a classification system for intraocular retinoblastoma that has been shown to have prognostic significance for maintenance of sight and control of local disease at a time when surgery and external-beam radiation therapy (EBRT) were the primary treatment options.
Group I: very favorable for maintenance of sight
- Solitary tumor, smaller than 4 disc diameters (DD), at or behind the equator.
- Multiple tumors, none larger than 4 DD, all at or behind the equator.
Group II: favorable for maintenance of sight
- Solitary tumor, 4 to 10 DD at or behind the equator.
- Multiple tumors, 4 to 10 DD behind the equator.
Group III: possible for maintenance of sight
- Any lesion anterior to the equator.
- Solitary tumor, larger than 10 DD behind the equator.
Group IV: unfavorable for maintenance of sight
- Multiple tumors, some larger than 10 DD.
- Any lesion extending anteriorly to the ora serrata.
Group V: very unfavorable for maintenance of sight
- Massive tumors involving more than one half of the retina.
- Vitreous seeding.
There is a new classification system for retinoblastoma, which may offer greater precision in stratifying risk for newer therapies. The International Classification for Intraocular Retinoblastoma that is used in the current Children’s Oncology Group treatment studies, as well in some institutional studies, has been shown to assist in predicting those who are likely to be cured without the need for enucleation or EBRT.[1-4]
- Group A: Small intraretinal tumors away from foveola and disc.
- All tumors are 3 mm or smaller in greatest dimension, confined to the retina and
- All tumors are located further than 3 mm from the foveola and 1.5 mm from the optic disc.
- Group B: All remaining discrete tumors confined to the retina.
- All other tumors confined to the retina not in Group A.
- Tumor-associated subretinal fluid less than 3 mm from the tumor with no subretinal seeding.
- Group C: Discrete local disease with minimal subretinal or vitreous seeding.
- Tumor(s) are discrete.
- Subretinal fluid, present or past, without seeding involving up to one-fourth of the retina.
- Local fine vitreous seeding may be present close to discrete tumor.
- Local subretinal seeding less than 3 mm (2 DD) from the tumor.
- Group D: Diffuse disease with significant vitreous or subretinal seeding.
- Tumor(s) may be massive or diffuse.
- Subretinal fluid present or past without seeding, involving up to total retinal detachment.
- Diffuse or massive vitreous disease may include “greasy” seeds or avascular tumor masses.
- Diffuse subretinal seeding may include subretinal plaques or tumor nodules.
- Group E: Presence of any one or more of the following poor prognosis features.
- Tumor touching the lens.
- Tumor anterior to anterior vitreous face involving ciliary body or anterior segment.
- Diffuse infiltrating retinoblastoma.
- Neovascular glaucoma.
- Opaque media from hemorrhage.
- Tumor necrosis with aseptic orbital cellulites.
- Phthisis bulbi.
- Murphree L: Staging and grouping of retinoblastoma. In: Singh A, Damato B: Clinical Ophthalmic Oncology. Philadelphia, Pa: Saunders Elsevier, 2007, pp 422-7.
- Zage PE, Reitman AJ, Seshadri R, et al.: Outcomes of a two-drug chemotherapy regimen for intraocular retinoblastoma. Pediatr Blood Cancer 50 (3): 567-72, 2008. [PUBMED Abstract]
- Shields CL, Mashayekhi A, Au AK, et al.: The International Classification of Retinoblastoma predicts chemoreduction success. Ophthalmology 113 (12): 2276-80, 2006. [PUBMED Abstract]
- Novetsky DE, Abramson DH, Kim JW, et al.: Published international classification of retinoblastoma (ICRB) definitions contain inconsistencies--an analysis of impact. Ophthalmic Genet 30 (1): 40-4, 2009. [PUBMED Abstract]