Retinoblastoma and treatment: A current evaluation of advanced therapy

Table 2 International classification of retinoblastoma

Group	Subgroup	Quick reference	Features
A	A	Small tumor	size ≤ 3 mm
B	B	Larger tumor	Size > 3 mm
		Macula	≤ 3 mm to foveola
		Juxtapapillary	≤ 1.5 mm to disc
		Subretinal fluid	Clear subretinal fluid ≤ 3 mm from margin
C	C1	Focal seeds	Subretinal seeds ≤ 3 mm from tumor
	C2		Vitreous seeds ≤ 3 mm from tumor
	C3		Both subretinal and vitreous seeds ≤ 3 mm from tumor
D	D1	Diffuse seeds	Subretinal seeds > 3 mm from tumor
	D2		Vitreous seeds > 3 mm from tumor
	D3		Both subretinal and vitreous seeds > 3 mm from tumor
E	E	Extensive retinoblastoma	> 50% globe involvement or
			Neovascular glaucoma
			hemorrhage in anterior chamber, vitreous, or subretinal space
			Invasion to postlaminar optic nerve, choroid (> 2 mm), sclera, orbit, anterior chamber

Source: Adapted from[7].