Definition:
- Malignant intraocular tumor arising from retinal precursor cells.
- Most common primary eye cancer in children.
Epidemiology
- Usually diagnosed before age 5.
- ~60% sporadic (unilateral), ~40% hereditary (bilateral or familial).
Genetics
- Caused by RB1 tumor suppressor gene mutation.
- Hereditary RB1 mutation → risk of bilateral tumors + later secondary malignancies (osteosarcoma, soft tissue sarcoma).
Clinical Features
- Leukocoria (white pupillary reflex) – most common presenting sign
- Strabismus, poor vision
- Rarely: glaucoma, proptosis if advanced
Diagnosis
- Ophthalmologic exam with fundus visualization
- Imaging: MRI preferred to avoid radiation
- Genetic testing for RB1 mutation
Treatment
- Goals: save life, preserve vision, minimize long-term toxicity
- Options:
- Enucleation – for large/unilateral tumors
- Focal therapy – laser photocoagulation, cryotherapy, thermotherapy
- Systemic chemotherapy (chemo-reduction) – vincristine, carboplatin, etoposide
- Intra-arterial or intravitreal chemotherapy – localized high-dose therapy
Pharmacist Considerations
- Drug selection: dose carefully for small children, often combination chemo (vincristine, carboplatin ± etoposide).
- Toxicity monitoring: myelosuppression, neuropathy, renal/hearing function (cisplatin).
- Supportive care: hydration, antiemetics, growth factor support if needed.
- Long-term: monitor for secondary malignancies in hereditary RB1 mutation.
Quick Clinical Pearls
- Bilateral tumors → almost always hereditary
- Leukocoria = hallmark sign, urgent referral
- Enucleation = curative in advanced unilateral cases
- Chemotherapy often used to shrink tumor for focal therapy or eye preservation