What is Retinoblastoma?

Types of retinoblastoma:

Hereditary Retinoblastoma:

• Bilateral: Affects both eyes due to a genetic mutation in the RB1 gene inherited from a parent. Increases risk of multiple tumors in both eyes.
• Unilateral: Affects one eye with a germline mutation in the RB1 gene. Risk of other cancers later in life.

Non-Hereditary (Sporadic) Retinoblastoma:

• Unilateral: Affects one eye due to a spontaneous mutation in retinoblast cells, not inherited.
• Bilateral: Rare type affecting both eyes; mutations occur independently in retinoblasts, not hereditary.

Symptoms of Retinoblastoma

• White Pupil (Leukocoria): White or cloudy pupil seen in flash photographs due to a tumour blocking the normal red reflex.
• Strabismus (Crossed Eyes): Sudden or persistent misalignment of the eyes, one eye deviating inward or outward.
• Reduced Vision: Decreased vision in one or both eyes, observed as lack of responsiveness, squinting, or difficulty tracking objects.
• Eye Pain or Redness: Pain, redness, or irritation in the eye due to tumour presence or inflammation.
• Changes in Eye Appearance: Swelling, inflammation, or noticeable changes in eye color or size, such as bulging or enlargement.
• Changes in Eye Movement: Difficulty moving the eye in certain directions if the tumour affects eye muscles.
• Poor Red Reflex: Absence or abnormality in the red reflex during eye examination with an ophthalmoscope.

When to see a doctor?

Take a doctor's appointment if you are getting tired quickly and need to know why. Your haemoglobin count has fallen if you observe the above Retinoblastoma symptoms or during a blood test.

Causes of Retinoblastoma

Hereditary Retinoblastoma:

• Inherited mutated RB1 gene increases risk, often affecting both eyes early in life.
• Higher risk for second primary malignancies later.

Non-Hereditary (Sporadic) Retinoblastoma:

• Spontaneous RB1 gene mutations in retinoblastoma cells.
• Usually affects one eye, diagnosed at a slightly later age than hereditary cases.

Note:

• RB1 gene mutations are the main cause, but not all carriers develop retinoblastoma.
• Other genetic changes or environmental factors may also contribute.

What are the Risk Factors of Retinoblastoma?

• Genetic Mutations: Mutations in the RB1 gene, inherited or spontaneous, significantly increase risk. Family history or known RB1 mutations elevate risk.
• Age: Primarily affects young children, most cases diagnosed before age 5; risk decreases with age.
• Heredity: Family history of retinoblastoma or RB1-related cancers increases risk, especially with affected parents or siblings.
• Gender: Slightly more common in girls than boys.
• Race and Ethnicity: Affects all races and ethnicities, with some populations possibly having a slightly higher incidence.
• Environmental Factors: While genetic mutations are primary, roles of environmental factors need further clarification.

Complications of Retinoblastoma:

• Vision Loss: Tumour size and location can lead to impaired or lost vision in affected eye(s). Early diagnosis and treatment are crucial for preserving vision.
• Metastasis: Untreated retinoblastoma may spread to brain, bones, or lymph nodes, complicating treatment and prognosis.
• Secondary Cancers: Higher risk, especially in hereditary cases, for developing other cancers like osteosarcoma or soft tissue sarcomas.
• Emotional Impact: Diagnosis and treatment can significantly affect child and family emotionally. Coping with treatment challenges and potential vision loss is stressful.
• Long-Term Follow-Up: Survivors need lifelong monitoring for late effects, recurrence, and secondary cancers through regular medical examinations.
• Family Impact: Diagnosis and treatment strain families emotionally and financially, requiring support and resources for coping.

Diagnosis of retinoblastoma:

• Clinical Examination: Ophthalmologist or pediatrician assesses eyes and overall health, looking for white pupil (leukocoria), strabismus (crossed eyes), or other visual abnormalities indicating retinoblastoma.
• Ophthalmoscopy and Fundus Photography: Use of ophthalmoscope to examine retina, and fundus photography for detailed imaging and monitoring.
• Ultrasound (Ocular Ultrasonography): Provides internal eye structure visualization, especially useful if cataracts obstruct view.
• Imaging Studies: MRI or CT scan to evaluate tumour extent and potential spread beyond the eye.
• Biopsy and Pathological Examination: Sometimes used to confirm diagnosis and determine retinoblastoma type (heritable or non-heritable).

Treatment retinoblastoma:

• Intra-Arterial Chemotherapy: Targeted delivery of anticancer drugs into the ophthalmic artery to shrink tumours, reducing the need for systemic chemotherapy or radiation.
• Systemic Chemotherapy: Administered orally or intravenously to target cancer cells throughout the body, used for larger tumours or advanced cases.
• Focal Therapies: Laser therapy (photocoagulation) or cryotherapy (freezing) to destroy small retinal tumours, preserving vision.
• Radiation Therapy: External beam radiation using high-energy X-rays, reserved for cases where other treatments are not feasible, with caution due to long-term risks.
• Enucleation: Surgical removal of the eye for large or aggressive tumours that cannot be treated while preserving vision, followed by placement of a prosthetic eye.
• Intraocular Focal Therapy: Implantation of devices like radioactive plaques or beads into the eye for targeted radiation, used in localized cases.
• Clinical Trials: Participation offers access to experimental treatments and therapies under investigation.