Retinoblastoma

Intraocular Retinoblastoma: localized to the eye. It 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. ⁽¹⁾⁽²⁾
Extraocular Retinoblastoma: extends beyond the eye. It may be confined to the tissues around the eye (orbital retinoblastoma), it may have spread to the central nervous system, or it may have spread systemically to the bone marrow or lymph nodes (metastatic retinoblastoma). ⁽³⁾

Enucleation: The surgical procedure that involves removal of the entire globe and its intraocular contents, with preservation of all other periorbital and orbital structures. ⁽⁴⁾

Exenteration: surgical procedure involving removal of the entire globe and its surrounding structures including muscles, fat, nerves, and eyelids (extent determined by disease being treated). ⁽⁴⁾

Local treatment: Treatment that is administered by the ophthalmologist directly to the tumor including: ^(5-12)

1) Cryotherapy through a cryoprobe that uses extreme cold to destroy tumor tissue on the peripheral retina.

2) Laser therapy traditional photocoagulation (argon laser), in which the laser was applied around the tumor to target the tumor vasculature.

3) Brachytherapy (plaque radiation therapy) which can provide an effective means for local control.

4)  Transthermal thermotherapy which is application of infrared light directly to the tumor.

5) Intravitreal chemotherapy intravitreal injection of melphalan or topotecan to control vitreous seeds.

6) Intra-arterial chemotherapy Direct delivery of chemotherapy melphalan into the eye via cannulation of the ophthalmic artery.

The International Intraocular Retinoblastoma Classification Grouping System ^(13-15)

Group A

·  Small intraretinal tumors away from the 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 other tumours confined to the retina not in Group A.

·  Tumour-associated subretinal fluid less than 3 mm from the tumour with no subretinal seeding.

·  Tumour located closer than 3 mm to the optic nerve or fovea.

Group C

· Discrete local disease with minimal subretinal or vitreous seeding.

· Subretinal fluid, present or past, without seeding involving up to one-fourth of the retina

· Local fine vitreous seeding may be present close to the discrete tumor.

· Local subretinal seeding less than 3 mm (2 DD) from the tumor

Group D

· Diffuse disease with significant vitreous or subretinal seeding.

· Tumour(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 tumour masses.

· Diffuse subretinal seeding may include subretinal plaques or tumour nodules.

Group E

·  Presence of any one or more of the following poor prognosis features:

1- Tumour touching the lens.

2-  Tumour anterior to anterior vitreous face involving ciliary body or anterior segment.

3-  Diffuse infiltrating retinoblastoma.

4- Neovascular glaucoma.

5- Opaque media from haemorrhage.

6-  Tumour necrosis with aseptic orbital cellulites.

7-  Phthisis bulbi.

Unilateral advanced intraocular group D disease: Large tumors filling the vitreous for which there is little or no likelihood of restoring vision, extension of tumor to the anterior chamber, or diffuse extensive intraocular distribution of RB seeds whether subretinal or in vitreous. ^(16)(17)

Useful vision: The retention of functional visual acuity, sufficient for age-appropriate visual tasks. It varies with age, tumour location, and treatment goals. ⁽¹⁸⁾