Encyclopedia - Retinoblastoma

Who contracts retinoblastoma?
What are the signs of retinoblastoma?
How is retinoblastoma treated?

Retinoblastoma is the most common eye cancer of children, occurring in one of every 20,000 births. Some 300 cases are diagnosed every year in the United States, usually at about 18 months of age.

Who contracts retinoblastoma?

Retinoblastoma is often an inherited condition, although it can occur without a family history. It was the first cancer to be directly associated with a genetic abnormality, deletions, or mutations of one specific region of chromosome 14.

If genetic testing finds such a chromosomal abnormality in a family, there is a 45 percent to 50 percent chance that the parents will have another child with retinoblastoma. If there is no family history and no mutation is found, the risk is only 2 percent to 5 percent.

If retinoblastoma occurs in one child, young brothers and sisters should be observed for signs of the cancer. New retinoblastomas are rarely seen after the age of 7.

What are the signs of retinoblastoma?

In about three-quarters of those cases, the first sign of retinoblastoma is an unusual whiteness of the pupil of the affected eye, which may lack vision. It can be accompanied by strabismus, an abnormal deviation of the line of sight of the eye. In some cases, both eyes are affected. Untreated, the cancer can spread from the eye to the orbit, the socket containing the eye, and then along the optic nerve to the brain.

Because other conditions such as congenital cataract and Toxocara caris can cause symptoms resembling retinoblastoma, the diagnosis usually is made by specialized blood tests, CAT scans, ultrasound evaluations, and an examination during which the young patient is anesthetized. In about one of every 20 cases, a biopsy may be needed for a definitive diagnosis.

How is retinoblastoma treated?

Until recently, the standard treatment for retinoblastoma was enucleation, which is removal of the affected eye, or radiation therapy. If both eyes are affected, the one with the largest tumor can be removed and the other eye can receive radiation therapy. Enucleation successfully eliminates the cancer in 90 percent of the cases.

In recent years, the team of specialists treating retinoblastoma -- an ophthalmic oncologist, pediatric oncologist, and radiation therapist -- has favored radiation treatment, so the child can keep the eye. But evidence suggesting that radiation may increase the risk of other cancers has led to a number of studies focusing on a combination of chemotherapy and such modalities as laser therapy and freezing. The effectiveness of this treatment combination is being assessed.