Retinoblastoma

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Retinoblastoma is a cancerous tumour affecting the retina (inner layer of nerve tissue in the eye that senses light and transmit images to the brain) and occurs when the nerve cells in the retina develop genetic mutations. It is a cancer of early childhood, affecting 1 in every 15,000- 18,000 children.

It can affect developing fetuses in the womb, newborn and children. It is typically diagnosed in children before 7 years of age, and can occur in one (unilateral) or both (bilateral) eyes. In about two-thirds (60%) of all cases, only one eye is affected.

If left untreated, the tumour cells can invade beyond the eyeball into surrounding structures, as well as spread to the other parts of the body, including the brain and spine, becoming a life-threatening disease.

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The condition may be found during routine eye examinations of young babies and toddlers. Otherwise, a child should be referred to us for review if parents notice one or more of the following features suggestive of retinoblastoma:

• Leukocoria or a white colour of the pupil (the central portion of the eye that is usually black/red), especially with flash photography
• A strabismus or misaligned eye (one eye turns in/out/up/down when the child is looking straight ahead)
• Vision problems
• Red or irritated eyes
  

​This cancer develops in the retina due to a faulty RB1 gene. There are two types of retinoblastoma, sporadic and heritable. In sporadic retinoblastoma, the faulty RB1 gene is present only in tumour cells. The retinoblastoma tumour usually only affects one eye and is often diagnosed at 24 months of age. Children with sporadic retinoblastoma are usually not at risk to pass down the disease to their children.

In heritable retinoblastoma, the faulty RB1 gene is present in all cells of the body. The retinoblastoma tumour usually develops in both eyes (although 15% may only have one eye affected) and is usually diagnosed earlier at 12 months of age. Children with heritable retinoblastoma have a lifetime risk of developing other cancers/tumours, and also passing down the condition to their future children.

​The diagnosis of retinoblastoma depends primarily on findings seen on eye examination. Hence, a thorough examination is of utmost importance, and may sometimes be performed with child under sedation or general anaesthesia. When diagnosed early, most children can be treated successfully and with preservation of their vision.

​Most patients with retinoblastoma can be cured, especially if the disease is confined within the eye. If left untreated, the cancer can spread out of the eye and to other parts of the body, where it becomes much harder to treat or may even result in loss of life. Hence, early diagnosis and treatment are important. 

Management of retinoblastoma includes:

1. Routine eye screening (e.g. in children with family history or past history of retinoblastoma)

2. Detailed eye examination for diagnosis of retinoblastoma includes:

• Examination under general anaesthesia
• Digital Imaging of tumour
• Magnetic resonance imaging (MRI) of the brain and eyes.
• Further investigations (bone-marrow aspiration or spinal tap) if there is spread of the cancer beyond the eyeballs
  

3. Treatment depends on a) whether one or both eyes are affected, b) the extent of cancer involvement within the eyeball, or c) whether the tumour has spread beyond the eyeball. Treatment options includes:

• Focal laser or cryotherapy of tumour within eye
• Chemotherapy (systemic intravenous, intra-arterial, intravitreal)
• Radiation therapy
• Enucleation (removal of the eyeball with the tumour within) and orbital implant (usually put in in the same operation to fill the volume left by the missing eyeball)
• Ocular prosthesis
  

4. Cancer genetics – useful in understanding how the condition is inherited and whether there is a risk to other family members and off-springs

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Fundus photos showing retinoblastoma affecting both eyes (top 2 photos, pre-treatment)

Large calcified residual tumour post treatment (bottom 2 photos)

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​Details depend on the type of treatment, and your doctor in charge will discuss them with you.

General preparations include following the fasting instructions, dressing your child in loose-fitting and comfortable clothes, and giving your child routine medicines with small sips of water, unless instructed not to. Inform your doctor if your child is unwell, has a history of allergy or reaction to any medications, drugs or food.

Details depend on the type of treatment, and your doctor in charge will discuss them with you.

General post-surgical eye-care: Leave the eye dressing on (if any), and remove only for eye drops instillation, unless otherwise instructed. There may be some discomfort in the first few days, and you can give your child the analgesics prescribed for pain relief.

Please keep to the scheduled appointment with your child's doctor, as follow-up care is crucial in preventing post-operative complications.