This week marks International Rare Disease Day which aims to raise awareness of rare conditions. One such rare condition is childhood eye cancer, which affects up to 50 children in the UK under the age of five each year.
Recognising this form of cancer quickly, and getting medical treatment, can make all the difference; that's why it is important for parents, carers and medical professionals to be aware of the signs and symptoms and to know what to do to help.
We spoke to Julie Firth of the Childhood Eye Cancer Trust to find out how to spot childhood eye cancer and what can be done to treat it.
What is childhood eye cancer?
Retinoblastoma (Rb) is a fast-growing eye cancer of early childhood, developing in the cells of the retina - the light sensitive lining of the eye.
Retinoblastoma occurs in two forms: a 'genetic' form (otherwise known as heritable) and a non-genetic form, known as non-heritable. Approximately 45 percent of children with retinoblastoma have the heritable form of the disease and have a 50 percent chance of passing on the disease to their own children - they also have an increased risk of developing a second cancer later on.
In about two thirds of children, only one eye is affected (unilateral), but in one third tumours develop in both eyes (bilateral).
Are children born with it?
Children with the heritable form of the disease are usually born with a tumour or tumours in their eyes. Children with the non-heritable type can develop tumours at any stage during early childhood. The risk of developing tumours reduces beyond the age of five.
Do we know what causes it?
In children with the heritable form, there is a genetic malfunction. This affects all or many cells in their body. In some children with this form of retinoblastoma, the altered RB1 gene is inherited from a parent; in some cases, however, the alteration in this gene occurs during fetal development. It is not known what causes the alteration in the gene. It is most likely to be a random mistake (or mutation) in the copying process which occurs when a cell divides.
For children with non-heritable retinoblastoma, this form is also caused by a mistake (mutation) in the RB1 gene, but this occurs as a random event in one cell within the retina. This mistake is then followed by a series of other genetic changes, which cause the tumour to form. Children with this form of the disease develop one tumour in one eye only and are not at risk of passing this on to their offspring.
How common is it?
It is rare, with around 40 to 50 cases diagnosed in the UK every year - equating to approximately 1:15,000 children.
What are the signs to look out for?
There are six mains signs of retinoblastoma to look out for:
- An abnormal appearance of the pupil, which tends give a white, cloudy or jelly-like reflection to light. This is usually only visible to the naked eye in low artificial lighting, or in photographs where a flash has been used. Some people say it looks like a cat's eye, caught in the light.
- A squint, or 'lazy eye'.
- An absence of red eye in one eye in a photograph.
- A change to the colour of one iris.
- A red and irritated eye without infection.
- Sudden deterioration of vision.
You can find more information, including a downloadable leaflet with images of all the signs of childhood eye cancer, at www.chect.org.uk
What should I do if I think my child has these symptoms?
If you are concerned, you should visit your GP or a local ophthalmology (eye) department and ask for an urgent examination. At your appointment your health professional should carry out a 'Red Reflex' test. In a darkened room; they will use a medical torch (ophthalmoscope) to check the eyes for anything unusual. If they have any concerns they will refer your child quickly for further investigation. More information on the red reflex test is available here.
Are there any other conditions which may have similar symptoms?
Yes - it is important to remember that retinoblastoma is rare. The 'white' eye sign in particular can just be the light reflecting off of the back of the eye, but we always advise parents who see this in a photo to get it checked out to rule out any serious eye conditions.
White eye could also be caused by:
Strabismus (Squint) - If the eyes are not properly aligned they do not gaze in the same direction. At a certain angle light will be reflected back out of the eye from the optic nerve, resulting in the white eye effect. Sometimes an absence of red eye is seen. Remember that a squint can also be a symptom of retinoblastoma which is why it is important to have a full check up carried out.
Cataract - A clouding that develops in the lens of the eye, which may show up as the white eye effect in a photo. Surgery can treat this condition.
Persistent Hyperplastic Primary Vitreous - The vitreous is the jelly-like substance inside the eye. This condition is due to an embryological disorder and results in a cataract (above) or a scarred retina (film of the eye).
Vitreous haemorrhage (Rhegmatogenous RD) - Small amounts of blood leak into the jelly in the eye, possibly from a tiny tear in the retina, preventing much of the light passing through to the retina and potentially causing white eye.
Astrocytoma - a rare, benign tumour of the retina and can be associated with a condition that also affects the skin called tuberous sclerosis. White eye can be caused in a similar way to retinoblastoma.
ROP (Retinopathy of prematurity) - Disorganised blood vessel growth in premature babies causing a scarred retina.
Coats/Norries/FEVR - While still in the womb, the retina in the eye does not develop properly, or later on there may be changes to the blood vessels in the eye.
Toxocariasis/Toxoplasmosis - Parasitic infection causing damage to the retina.
Medulloepithelioma - Tumour of an area of the eye, which is rare.
What treatment is available?
There are a range of treatments available depending on how early the child is diagnosed and the type of retinoblastoma they have. These include cryotherapy, laser therapy, chemotherapy, radiotherapy and surgery (removal of the eye).
Do most children make a full recovery?
The UK survival rate for retinoblastoma is very high at 98 percent.. However, 70 percent of children with unilateral disease will lose an eye to save their life. Many others will suffer vision loss and, in extreme cases, complete blindness.
Please remember that retinoblastoma is rare, with just 40 -50 new cases diagnosed in the UK each year. However, we always recommend you get your child's eyes checked out as soon as possible if you notice any of the signs and symptoms, if only to rule out a serious eye condition.
For more information about all aspects of childhood eye cancer, visit www.chect.org.uk