In the early stages, retinoblastoma causes a white pupillary reflex (leukocoria) or strabismus (squint), which is often noticed by the parents (picture 1).
Early detection is vital to save the vision.
Every child who is noted to have a white reflection in the pupillary aperture should always be referred to an ophthalmologist on the next working day as should any child who, after having developed straight eyes, begins to squint.
Retinoblastoma may already develop during foetal life.
The majority of patients are under 3 years of age; patients aged over 8 are rare.
Over half of all children with retinoblastoma have tumours in both eyes.
Over half of retinoblastomas are inherited as an autosomal dominant trait.
However, in most cases hereditary retinoblastomas are due to new germ line mutations and there are, therefore, no other affected relatives.
Almost half of the patient's children will inherit the disease.
A gene test on a blood sample detects the mutation in 98% of the cases.
Unless treated promptly, the tumour will rapidly blind the eye and in extreme cases prove to be fatal.
Signs and symptoms
The most common symptom is leukocoria, a white reflex seen in the pupillary aperture (picture 1).
Leukocoria is usually noticed by the parents at home in dim light when the pupil is dilated.
The reflex is often obvious in family photographs taken with a flash.
Leukocoria suspected by parents is always an indication for consultation with an ophthalmologist on the next working day, even if the examining physician cannot confirm any abnormality within the eye. Unit for eye diseases should be consulted in order to arrange the appointment as smoothly as possible.
In a typical case, an abnormal white area may be seen in the fundus reflex.
Manifest strabismus in the affected eye is the second most common finding, and it occurs before leukocoria.
Strabismus typically develops in a child whose eyes have already been aligned for some time.
Regardless of the age of the child, a child who develops manifest strabismus should always be referred to an ophthalmologist as an emergency case. Unit for eye diseases should be consulted before referral.
The outward appearance of the affected eye is usually normal.
Treatment
Treatment methods that preserve both the eye and vision have advanced greatly.
The most common first-line treatment is chemoreduction which involves the reduction of the tumour volume with cytotoxic drugs.
After the tumour has been shrunk, or if the tumour is initially small, it can be destroyed with laser therapy, cryocoagulation or plaque radiotherapy.
External beam radiotherapy is reserved only for special cases.
Advanced tumours necessitate the enucleation of the affected eye.
Treatment is usually centralised at specialist centres.
Screening
If a couple with a family or personal history of retinoblastoma plans pregnancy, they should be referred for genetic counselling Genetic Counselling.
Gene testing will reveal whether the child is at risk of inheriting retinoblastoma.
If in vitro fertilisation is used, it is possible to choose a healthy embryo.
Screening is essential if a child has inherited the retinoblastoma gene, or if the parents or siblings have a history of the disease and the inheritance status is not known.
An ultrasound examination can detect tumours in the foetus several weeks before the expected date of delivery. In such cases, the delivery can be induced earlier and treatment started.
If a genetic defect has been determined in the family earlier, a blood test taken right after birth will provide a rapid result within 1-2 weeks.
The fundi of the newborn must be examined without general anaesthesia during the first 24 hours after birth followed by an examination under general anaesthesia within the first week of life and regularly thereafter.
If the gene test result is negative, screening may be discontinued.