Intravitreal Injection of Chemotherapy for Retinoblastoma
Indications
- Vitreous Seeding
- Recalcitrant subretinal and retinal tumors
Drugs
- Melphalan hydrochloride
- use 50 mg lypohilized powder for IV injection
- 0.25-0.3 mg per 0.5 ml
- Deliver 25-30 ug in 0.05 ml
- Reconstitue in 0.9% normal saline
- Must be injected into the eye < 1 hour after being constituted
- Topotecan hydrochloride
- 20 μg in 0.04 ml (0.2 mg per 0.4 ml)
- Reconstitue in 0.9% normal saline
Tools
- 30-33 gauge needle for drug delivery
- EUA set up (lid speculum, indenter, indirect, condensing lenses, etc.)
- Tonopen
- Cryo machine
- Sterile Water
- 60 ml syringe
- kidney basin
Steps
- Call Pharmacy (x64300) 20 minutes before desired drug delivery time.
- Choose an injection site distant from any vitreous or retinal tumors
- Lower intraocular pressure to <10mmHg with digital massage
- Prep the eye with a drop of Betadine 5%
- Inject 2.5-3 mm from limbus directing the needle towards the center of the vitreous but avoid known vitreous seeds
- Before retracting the needle tip from the vitreous apply cryo to the injection site and the needle.
- Apply a drop of betadine
- Inspect vitreous and retina if desired
Source: The role of intravitreal chemotherapy for retinoblastoma. Manjandavida FP, Shields CL. Indian J Ophthalmology 2014;63(2):143
Follow-up
- Repeat EUA with plan to inject again for non-response in about 2 weeks
- If tumors appear to be dead, do one final injection (n+1 rule)