The staging of patients with retinoblastoma requires close coordination of radiologists, pediatric oncologists, and ophthalmologists. Several staging and grouping systems have been proposed for retinoblastoma. Overall assessment of retinoblastoma extension is documented by staging systems; intraocular extension, which is relevant for ocular salvage, is documented by grouping systems. For treatment purposes, retinoblastoma is categorized into intraocular and extraocular disease.
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 retinoblastoma has extended beyond the eye. It may be confined to the tissues around the eye (orbital retinoblastoma); it may have spread to the central nervous system (CNS); or, it may have spread systemically to the bone marrow or lymph nodes (metastatic retinoblastoma). Magnetic resonance imaging (MRI) can be useful in the evaluation of extrascleral and extraocular disease in children with advanced intraocular retinoblastoma. Optic nerve enhancement by MRI does not necessarily indicate involvement and cautious interpretation is needed. The detection of the synthetase of ganglioside GD2 mRNA by reverse transcriptase-polymerase chain reaction in the cerebrospinal fluid at the time of diagnosis may be a marker for CNS disease.
AJCC staging system
Several staging systems have been proposed over the years. The AJCC clinical and pathological classifications represent a consensus opinion around which a common language is used.
Clinical classification system