Retinoblastoma is a malignant tumor on the retina, the light-sensing part of the eye that is located in the back of the eye. This type of cancer can be present in one or both eyes.
What causes retinoblastoma?
Our eyes begin to develop very early in the womb. Rapidly growing cells in the eye, called retinoblasts, will eventually mature and form the retina. Sometimes, these specialized cells do not stop reproducing and form a tumor on the retina. These tumors might continue to grow, filling almost the entire vitreous humor (the jelly-like substances that fills the eyeball), but also break off and spread to other parts of the eye, and eventually outside to lymph nodes and other organs.
Who gets retinoblastoma?
Retinoblastoma occurs most often in children 5 years and under. It rarely occurs in adults. Between 200 and 300 children are diagnosed with retinoblastoma each year, affecting one in every 20,000. About 40 percent of all cases of retinoblastoma are inherited, meaning the cancer is passed on from parent to child. Retinoblastoma occurs about 75 percent of the time in one eye, and 25 percent of the time in both eyes.
What are the symptoms of Retinoblastoma?
Symptoms of retinoblastoma include:
- A pupil that appears white when light is shone into it, called leucocoria, might mean that a retinal tumor is present. Blood vessels in the back of the eye will normally reflect red.
- The eyes might not move or focus in the same direction.
- There might be eye pain.
- The pupil is constantly dilated.
- The eye(s) might be red.
How is retinoblastoma diagnosed?
An eye exam and imaging test given by an ophthalmologist (an eye doctor) can diagnose the condition.
If retinoblastoma is suspected, an ophthalmologist will need to examine the eye using special equipment to see the retina. Other tests might be conducted to determine the stage of the retinoblastoma, or how far it has spread. These tests include ultrasound, MRI scans, CT scans, bone scans, spinal tap, and bone marrow tests.
What are the stages of retinoblastoma?
Stages of retinoblastoma include:
- Intraocular retinoblastoma — This is the earliest stage of retinoblastoma, found in one or both eyes. It has not yet spread to tissue outside of the eye.
- Extraocular retinoblastoma — This type of cancer has either spread outside of the eye or to other parts of the body.
- Recurrent retinoblastoma — The cancer has come back or spread in the eye or to other parts of the body after being treated.
How is retinoblastoma treated?
Because it is usually found before it spreads outside of the sclera (white of the eye), retinoblastoma is highly curable, and there are many types of treatment that can also save eyesight. Treatments are selected based on the stage of cancer at the time of diagnosis. Options include:
- Photocoagulation — A laser is used to kill blood vessels that feed the tumor.
- Cryotherapy — Extremely low temperatures are used to kill cancer cells.
- Chemotherapy — Chemotherapy is a treatment given intravenously (injected into the vein), orally, or is injected into the fluid that surrounds the brain and spinal cord, called intrathecal chemotherapy. These powerful doses of cancer-killing medicine help kill or slow the growth of multiplying cancerous cells.
- Radiation therapy — Radiation might be given externally or internally. External-beam radiation therapy uses X-rays to kill cancer cells. Internal, or local radiation therapy, involves placing small amounts of radioactive material inside of or near the tumor to kill cancer cells.
- Enucleation — This is surgery to remove the eye.
What does the future hold for people with retinoblastoma?
More than 90 percent of children will survive more than five years after being diagnosed with retinoblastoma. Patients are able to retain about 85 percent of vision in the affected eye after treatment.
Hereditary forms of retinoblastoma are more likely to reoccur years after treatment. Therefore, close follow-up after treatment is important for these patients.
Is retinoblastoma preventable?
Because heredity and age play such large roles in retinoblastoma, the best prevention is through early detection. All babies should have a general eye exam at birth and then again at six months. A doctor will be able to detect any serious congenital problems or the appearance of retinal tumors. Newborns with a family history of this type of cancer should have a thorough eye exam a few days after birth, at six weeks, once every three months until age two, and once every four months until age three. The chance that a parent will pass on the DNA mutation that causes this cancer to their child is 1 in 2. A blood test can be used to determine if this mutation is present.
For adults, prevention means getting a thorough regular eye examination at least once a year and more often — as recommended by your ophthalmologist — if you have a personal or family history of eye disorders or diabetes.
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