Table 1.

Modern treatment of retinoblastoma: A 2020 Review. International classification of retinoblastoma (ICRB)

Group	Mnemonic	Features
A	Small tumor	Retinoblastoma ≤3 mm in basal diameter or thickness
B	Bigger tumor Beside the macula or optic nerve	Retinoblastoma >3 mm in basal diameter or thickness OR tumor location ≤3 mm from foveola tumor location ≤1.5 mm from optic disc tumor-associated subretinal fluid ≤3 mm from tumor margin
C	Contiguous seeds	Retinoblastoma with subretinal seeds ≤3 mm from tumor vitreous seeds ≤3 mm from tumor subretinal and vitreous seeds ≤3 mm from tumor
D	Diffuse seeds	Retinoblastoma with subretinal seeds >3 mm from tumor vitreous seeds >3 mm from tumor subretinal and vitreous seeds >3 mm from tumor
E	Extensive tumor	Retinoblastoma occupying >50% of the globe OR neovascular glaucoma opaque media from hemorrhage in subretinal space, vitreous, or anterior chamber invasion of postlaminar optic nerve, choroid (>2 mm), sclera, orbit, anterior chamber