Retinoblastoma is a rare cancer that originates in the retina, the light-sensitive tissue lining the back of the eye. Despite its rarity, it is the most common malignant tumour that starts in the eye in children. In India, many cases are diagnosed, typically affecting children before the age of five, with most cases occurring in children under the age of two.
Retinoblastoma is broadly categorised into two forms based on its genetic origin:
This accounts for 25% to 40% of cases. These patients have a mutation in the RB1 gene, which, when healthy, acts as a tumour suppressor. The mutated gene permits tumour formation. The mutation is found in the DNA of every cell in the patient's body. It is often inherited from a parent or can be a new mutation that begins with the patient. This type can be passed down to the next generation and usually develops before the age of one.
This accounts for 60% to 75% of cases. In these patients, the RB1 mutation is found only within the cancer cells. This form is not inherited or passed down. It is thought to occur when a single cell mutates randomly, begins dividing, and develops into a malignant tumour. This type is more likely to be diagnosed in children over the age of one.
Affects one eye (60% to 75% of cases). About 85% of these are the sporadic form, with the remainder being hereditary.
Affects both eyes and is almost always hereditary. Patients are typically diagnosed at a younger age (less than one year old) compared to those with the unilateral disease.
A rare form (5% of hereditary cases) where an associated tumour develops in primitive nerve cells in the brain. This is only seen in children with hereditary retinoblastoma.
The tumour is confined to the eyeball(s) and has not spread outside. Cancer cells may be in the retina or other parts of the eyeball, such as the choroid, ciliary body, or part of the optic nerve.
The cancer has spread beyond the eyeball(s). This may involve nearby tissue (like the eye socket or orbit) or distant areas, including the central nervous system (brain and spinal cord), liver, bone marrow, or lymph nodes.
Factors that may increase the risk of developing retinoblastoma include:
Most cases are diagnosed in children five years old or younger, typically before age two.
A genetic mutation in the RB1 gene can be passed down from a parent to a child.
Retinoblastoma symptoms are typically first observed in the eye. They may include:
An opaque white area in the pupil, known as leukocoria, which is caused by the tumour reflecting light. This is often visible in flash photographs.
Problems with eye movement, such as crossed eyes (strabismus).
Decreased vision in one eye.
Important: While these symptoms may be caused by a less serious condition, it is vital to consult a doctor immediately to rule out retinoblastoma or other health issues. Children exhibiting leukocoria should be seen by an ophthalmologist as soon as possible, as the condition can threaten the patient's vision.
Diagnosing retinoblastoma typically avoids a biopsy, as retrieving cancer cells from the eye may risk spreading the disease. Instead, diagnosis relies on detailed imaging and eye examinations:
The first sign is often a white reflection in the pupil noticed during a routine paediatrician appointment.
The paediatrician should refer the patient to an ophthalmologist trained in diagnosing eye cancers, such as an ocular oncologist, for a full diagnostic exam.
Funduscopic eye exam
The pupils are dilated to allow examination of the retina. Anaesthesia may be used for this exam.
Ultrasound of the eye
Magnetic Resonance Imaging (MRI) scan
Blood tests
DNA and/or genetic testing
To determine if the disease is hereditary.
Staging is the process doctors use to determine if the cancer has spread within the eye or to other body parts, which is crucial for planning treatment.
The tumour is confined to the eye. The eye has not been removed, and the tumour was treated without surgery.
The tumour was confined to the eye, which has been removed. No cancer cells remain after removal.
The tumour was confined to the eye, which has been removed. Cancer cells remain but are visible only under a microscope.
Stage IIIa: Cancer has spread from the eye to tissues immediately surrounding the eye socket.
Stage IIIb: Cancer has spread from the eye to lymph nodes near the ear or in the neck.
Stage IVa: Cancer has spread to one or more distant parts of the body, such as the bone or liver.
Stage IVb: Cancer has spread to the brain or spinal cord. It may also have spread to other distant parts of the body.
Save the life. Save the eye. Save the vision.
A multidisciplinary team, including medical oncologists, surgical oncologists, radiation oncologists, ocular pathologists, and geneticists, will work together to create a customised treatment plan. Experts at SSCHRC are part of world-class teams dedicated to the care of retinoblastoma patients.
Treatment options may include:
Intra-arterial chemotherapy
Intravitreal chemotherapy
High-dose chemotherapy with stem cell rescue
Brachytherapy
Laser therapy
Surgery
Specialised ocular pathology and tissue harvesting
Chemotherapy uses drugs to kill cancer cells, control their growth, or relieve symptoms. It can be a single drug or a combination, depending on the cancer type and growth rate.
Methods of delivery include:
Lasers are used to destroy retinoblastoma tumours. This is often an effective option for small tumours confined to the retina, particularly those not involving the optic disc or the macula (the most critical part of the retina for vision). It is frequently used following chemotherapy to eliminate remaining cancer cells.
Enucleation Surgery: This is the surgical removal of the eye. It may be necessary when the tumour fills more than half the eyeball, involves other structures in the eye, or if the retina is detached. Following the procedure, the child is fitted with an ocular implant and later an artificial eye. Due to advancements in detection and treatment, enucleation is less common than in the past.
This procedure uses intense cold to destroy tumour cells. A special probe is inserted into the tumour and cooled significantly, forming a ball of ice that freezes and destroys the cancerous tissue. Cryotherapy is generally performed as an outpatient procedure and is less invasive than traditional surgery.
Radiation therapy uses potent, focused energy beams to kill cancer cells. Advanced techniques allow doctors to accurately target the tumour while minimising damage to surrounding healthy tissue.
Following treatment, retinoblastoma patients require regular cancer screenings and follow-up care to monitor for cancer recurrence. This is especially important for patients who had the hereditary form of the disease, as they face an increased risk of developing a second cancer later in life.