Retinoblastoma

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Retinoblastoma
Classification and external resources
Rb tumours taken with a retinoscan before and during chemotherapy
ICD-10	C69.2
ICD-9	190.5
ICD-O:	M9510/3
OMIM	180200
DiseasesDB	11434
MedlinePlus	001030
eMedicine	oph/346
MeSH	D012175

Retinoblastoma (Rb) is a rapidly developing cancer which develops in the cells of the retina, the light detecting tissue of the eye^[1]. In the developed world, Rb has one of the best cure rates of all childhood cancers (95-98%), with more than nine out of every ten sufferers surviving into adulthood. Retinoblastoma is a very treatable cancer. The disease gained national attention in 2007 when NBA player Derek Fisher's daughter was diagnosed with it, causing him to miss time in the NBA Playoffs.

[edit] Classification

There are two forms of the disease; a genetic heritable form and a non-genetic non-heritable form. Approximately 55% of children with Rb have the non-genetic form. If there is no history of the disease within the family, the disease is labelled "sporadic", but this does not necessarily indicate that it is the non-genetic form.

In about two thirds of cases, ^[2] only one eye is affected (unilateral retinoblastoma); in the other third, tumours develop in both eyes (bilateral retinoblastoma). The number and size of tumours on each eye may vary. The position, size and quantity of tumours are considered when choosing the type of treatment for the disease.

[edit] Signs and symptoms

Leukocoria in a child with retinoblastoma

Crossed eyes in a child with retinoblastoma

The most common and obvious sign of retinoblastoma is an abnormal appearance of the pupil, leukocoria^[1]. Other less common and less specific signs and symptoms are: deterioration of vision, a red and irritated eye, faltering growth or delayed development. Some children with retinoblastoma can develop a squint^[3], commonly referred to as "cross-eyed" or "wall-eyed" (strabismus). However, retinoblastoma presence with advanced disease in developing countries and eye enlargement is a common finding.

Depending on the position of the tumors, they may be visible during a simple eye exam using an ophthalmoscope to look through the pupil. A positive diagnosis is usually made only with an examination under anesthetic (EUA). A white eye reflection is not always a positive indication of retinoblastoma and can be caused by light being reflected badly or by other conditions such as Coats's Disease.

In a photograph, the photographic fault red eye may be a sign of retinoblastoma, if in the photograph it is in one eye and not in the other eye.

[edit] Frequency of retinoblastoma

Retinoblastoma is rare and affects approximately 1 in 15,000 live births.^[4] In the UK around 40 to 50 new cases are diagnosed each year.

Most children are diagnosed before the age of five years old. In the UK bilateral cases usually present within the first year with the average age at diagnosis being 9 months. Diagnosis of unilateral cases peaks between 24 and 30 months.

[edit] Cause of retinoblastoma

In children with the heritable genetic form of retinoblastoma there is a mutation on chromosome 13, called the RB1 gene.^[5] The genetic codes found in chromosomes control the way in which cells grow and develop within the body.^[6] If a portion of the code is missing or altered (mutation) a cancer may develop.

The defective RB1 gene can be inherited from either parent, however in some children, the mutation occurs in the early stages of fetal development. It is not known what causes the gene abnormality; it is most likely to be a random mistake during the copy process which occurs when a cell divides.

[edit] Treatment

Historical image showing Gordon Isaacs, the first patient treated with the linear accelerator (external beam radiation therapy) for retinoblastoma in 1957. Gordon's right eye was removed January 11, 1957 because the cancer had spread. His left eye, however, had only a localized tumor that prompted Henry Kaplan (doctor) to try to treat it with the electron beam.

Treatment of retinoblastoma varies from country to country.^[7] The first priority is to preserve the life of the child, then to preserve the vision and thirdly to minimize any complications or side effects of the treatment. The exact course of treatment will depend on the individual case^[8] and will be decided by the Ophthalmologist in discussion with the Paediatric Oncologist.

Options for treatment include: chemotherapy (which can be administered locally through a thin catheter that is threaded through the groin through the aorta and the neck into the optic vessels), cryotherapy, radioactive plaques, laser therapy, external beam radiotherapy and surgery.^[9] Any combinations of these treatments may be adopted.

In recent years, there has been an effort to find alternatives to enucleation and radiation therapy.^[10]

[edit] See also

• Eye cancer
• Eye examination
• Retinoblastoma Protein

[edit] Additional images

Retinoblastoma rosette	MRI pattern of retinoblastoma with optic nerve involvement (sagittal enhanced T1-weighted sequence)	Aspect of trilateral retinoblastoma (MRI)	Ocular fundus aspect of retinoblastoma
Gross pathology of retinoblastoma tumor in enucleated eye of three year old female

[edit] References

[edit] External links

• Retinoblastoma at National Cancer Institute
• Retinoblastoma International
• Retinoblastoma information from MedlinePlus
• retinoblastoma at NIH/UW GeneTests
• Retinoblastoma at the Open Directory Project

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