Table 1

The American Joint Committee on Cancer (AJCC) eighth edition TNMH classification for retinoblastoma, Definitions for primary tumour staging (CT)

cTX	Unknown evidence of intraocular tumour
cT0	No evidence of intraocular tumour.
cT1	Intraocular tumour(s) with subretinal fluid ≤5 mm from the base of any tumour.
cT1a	Tumours ≤3 mm and further than 1.5 mm from the disc and fovea.
cT1b	Tumours >3 mm or closer than 1.5 mm to the disc and fovea.
cT2	Intraocular tumour(s) with retinal detachment, vitreous seeding or subretinal seeding.
cT2a	Subretinal fluid >5 mm from the base of any tumour.
cT2b	Tumours with vitreous seeding and/or subretinal seeding.
cT3	Advanced intraocular tumour(s).
cT3a	Phthisis or prephthisis bulbi.
cT3b	Tumour invasion of the pars plana, ciliary body, lens, zonules, iris or anterior chamber.
cT3c	Raised intraocular pressure with neovascularisation and/or buphthalmos.
cT3d	Hyphema and/or massive vitreous haemorrhage.
cT3e	Aseptic orbital cellulitis.
cT4	Extraocular tumour(s) involving the orbit, including the optic nerve.
cT4a	Radiological evidence of retrobulbar optic nerve involvement or thickening of the optic nerve or involvement of the orbital tissues.
cT4a	Extraocular tumour clinically evident with proptosis and orbital mass.