A rare cancer of the retina, the lightsensitive membrane at the back of the eye
- Usually develops before the age of 2
- Sometimes runs in families
- Gender and lifestyle are not significant factors
In the UK, about 1 in 20,000 babies is affected with retinoblastoma, a rare cancer of the retina (the light-sensitive membrane at the back of the eye). The condition can develop in one or both of the eyes, usually before a child reaches 2 years of age. About half of all cases are caused by an abnormal gene, which is located on chromosome 13 and is inherited in an autosomal dominant manner (see Gene disorders). This inherited form of retinoblastoma often affects both eyes. In the remaining, non-inherited cases, the cause is unknown, and usually only one eye is affected.
The most common symptom is the development of a whitened area behind the pupil. Impaired vision caused by retinoblastoma may lead to strabismus. Left untreated, the cancer can spread to other parts of the body.
What might be done?
If the doctor suspects that a child has retinoblastoma, he or she will refer the child to a specialist, who will examine the eyes, possibly under general anaesthesia. The child may also have blood tests to look for the abnormal gene. If retinoblastoma is confirmed, CT scanning or MRI may be done to see if the cancer has spread.
The aim of treatment is to cure the cancer and, if possible, to retain vision in the affected eyes. It is usually possible to destroy small cancerous tumours in the retina by freezing the tissue. However, surgical removal of the entire eye will probably be necessary to treat large tumours. Treatment with chemotherapy and radiotherapy may also be required if the cancer has spread.
What is the prognosis?
In most cases, the cancer can be cured, but the child’s vision may be severely impaired. Genetic counselling is available to relatives of an affected child and to adults treated for retinoblastoma in childhood. The siblings of an affected child should have regular eye tests.
From the 2010 revision of the Complete Home Medical Guide © Dorling Kindersley Limited.
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