Retinoblastoma

Introduction

Retinoblastoma is a congenital malignant tumour originating from the retina of the eye.

This tumour may be hereditary, particularly the bilateral form which forms about 30% of cases.

Most tumours however are sporadic (spontaneous mutation).

This is the third commonest cancer seen amongst children in developing countries. Most children present before five years of age.

It rarely occurs in older children. The prognosis with early presentation is excellent with a 95% chance of long term cure.

There is a high rate of development of tumours of other organs later in life in the hereditary form.

Causes of retinoblastoma

• Genetic (up to 40% of cases)
• Sporadic (in about 60% of cases)

Symptoms of retinoblastoma

The following are the symptoms of retinoblastoma

1. White, shiny spot (leukocoria) in the pupil, also known as the cat’s eye reflex is usually the first symptom in most patients
2. Squint (strabismus)
3. Visual loss
4. Protruding eyeball
5. Redness of the eye

Signs of retinoblastoma

The signs of retinoblastoma include the following:

1. Absent red reflex
2. Tumour in the retina on fundoscopy
3. Vitreous haemorrhage and retinal detachment on fundoscopy
4. Increased intraocular pressure (glaucoma)
5. Orbital cellulitis

Investigations

• Ultrasound scan of orbit
• Head CT or MRI scan
• Lumbar puncture for cerebrospinal fluid cytology
• Bone marrow aspirate

Treatment for retinoblastoma

Objectives

1. The treatment objectives of retinoblastoma include the following:
2. To arrest the progression of the tumour
3. To prevent distant spread of tumour
4. To achieve long term cure
5. To provide adequate supportive and palliative care in advanced disease

Non-pharmacological treatment

1. Enucleation of the affected eye is curative in the early stages
2. Prosthetic eye insertion
3. Laser therapy for focal control
4. Radiotherapy for local spread of the tumour
5. Counselling to help cope with psychological impact

Pharmacological treatment

A. Intraocular and extraocular retinoblastoma

Chemotherapy

Evidence Rating: [A]

• Vincristine, IV,
• Etoposide, IV,
• Carboplatin, IV,

Or

• Vincristine, IV,
• Etoposide, IV,
• Cyclophosphamide, IV,

B. Advanced disease with intracranial metastases

Palliative care with adequate pain and other symptom control

C. For treatment of vomiting

Evidence Rating: [A]

Metoclopramide, IV or oral,
100-400 microgram/kg 8

Or

Granisetron, IV,

• 40 microgram/kg (max. 3 mg) stat.
  May repeat 12 hourly if necessary

Or

• Granisetron, oral, 20 microgram/kg (max. 1 mg) within 1 hour before start of treatment

Then

• 20 microgram/kg 12 hourly for up to 5 days

Or

Ondansetron, IV,

Adult: 5 mg/m2 stat.

Repeat 8 hourly if necessary

Children: 12-18 years; 8 mg stat. (immediately before chemotherapy)

Or

Ondansetron, oral,

Adult: 8 mg 8 hourly, administered 30 minutes before the start of chemotherapy

Children:

• 12-18 years; 8 mg 8-12 hourly up to 5 days
• 1-12 years; 4 mg 8-12 hourly up to 5 days

D. For treatment of febrile neutropenia

Ceftriaxone, IV, 100 mg/kg daily

And

Gentamicin, IV, 5 mg/kg daily

And

(if still febrile after 48 hours, add
Cloxacillin, IV, 25-50 mg/kg 6 hourly And (if still febrile after 5 days, add)
Fluconazole, oral, 10 mg/kg daily

E. For treatment of anaemia and thrombocytopenia

Blood and blood product transfusions (See ‘Bleeding disorders‘)

Referral Criteria

All patients should be referred to a tertiary centre that can effectively treat retinoblastoma.