About this Cancer

Retinoblastoma is a tumor that occurs in the light sensitive lining of the eye known as the retina. It typically affects children under age six.  It can occur in two forms: an inherited form where there are often tumors in both eyes, and a non-inherited form where there is usually only a tumor in one eye.

Risk Factors

In the inherited tumors, retinoblastoma is caused by a genetic abnormality. Retinoblastoma occurs when a cell of the growing retina develops a mutation in the RB gene (a tumor suppresser gene). This mutation allows the cell to grow out of control and become cancer.

Sometimes, this mutation develops in a child whose family has never had eye cancer, but other times the mutation is present in several family members. If there is a mutation in the family, there is a 50 percent chance that an affected person's children will also have the mutation and a high risk of developing retinoblastoma.

If there is a new mutation in the family, the risk for developing retinoblastoma depends upon the specific mutation. Patients with mutations of this gene also have an increased risk of developing other tumors outside the eye.  Though rare, the tumor can spread to the eye socket, and to the brain, by means of the optic nerve.

The cause of the non-inherited tumors is unknown.

Cancer Symptoms

If there is a family history of retinoblastoma, a newborm should be examined soon after birth for any signs of the disease. In the other cases, the first sign is often a white pupil that does not reflect the light. A white glow in the eye may be seen in photographs taken with a flash; instead of the typical "red eye" from the flash, the pupil may appear white or distorted.

Irises that are two different colors, crossed eyes, and poor vision are other signs of retinoblastoma.  If the tumor is large, it may cause a painful, red eye.

Diagnostic Tests

Initailly, a CT (computerized tomography) scan of the eye and brain and possibly an MRI (magnetic resonance imaging) of the brain may be performed. Tests may also involve an examination, under anesthetic, in which an eye specialist, an ophthalmologist, will examine your child's eye while he or she is asleep. Several more examinations will be performed to check on the progress of treatment. An ultrasound, a painless scan that uses sound waves to examine the eye and the surrounding area, may be done.

A lumbar puncture, which involves the use of a needle to collect some spinal fluid from the spine, may be done to check for any spread of the tumor into the central nervous system. A blood test may be taken to look for the abnormal gene, especially if the tumor develops in both eyes and/or at a very young age.

Treatment

Treatment requires the coordination of a pediatric eye specialist and a pediatric cancer specialist.  Treatment is based on the number, position and size of the tumors in the eye. Treatments for the eye itself (local treatments) include:

• Cryotherapy, to freeze small tumors
•  Laser therapy, another treatment for small tumors
• A radioactive plaque, a small disc usually containing radioactive iodine, which can be stitched to the outer surface of the eye for slightly larger tumors
• Radiation therapy, localized treatment using targeted X-rays

Chemotherapy (treatment with anticancer drugs) may be given before the local treatments, or, before radiation therapy (localized treatment to the tumor using targeted X-rays), to help shrink the tumors. If the tumor is very large and the vision in the eye cannot be saved, the eye is removed (enucleation). An artificial eye is then fitted.

An eye specialist will examine the eye under anesthetic frequently to check that the cancer has not come back. Depending on the treatment, some patients may lose some of their sight.

Radiation therapy may be used and can cause long-term effects.  With new radiation techniques, however, many of these effects are being decreased. 

Due to the genetic component of retinoblastoma, genetic counseling is recommended. Genetic counseling and support are available for all families with a diagnosis of retinoblastoma.