What Is It?
Retinoblastoma, a cancerous tumor of the retina in the eye, is a rare form of cancer that affects children, most commonly before age 5. The retina is the nerve tissue at the back of the eye that senses light and sends images to the brain, which interprets these images.
The disease affects about one in every 15,000 to 20,000 children. According to the American Cancer Society, retinoblastoma is responsible for 5 percent of childhood blindness. However, with treatment, 85 percent of children with retinoblastoma maintain their sight.
Approximately 40 percent of retinoblastoma cases are hereditary. The hereditary form usually affects younger children (under age 2) and can affect one eye (unilateral) or both eyes (bilateral). However, unilateral retinoblastoma is usually not hereditary, and occurs most commonly in older children. And all cases of bilateral retinoblastoma are hereditary.
Children who develop retinoblastoma have an increased risk of developing other types of cancer later in life. The risk is higher in children with the hereditary type and children who have received radiation therapy or certain types of chemotherapy. Children who develop retinoblastoma in one eye have an increased risk of developing retinoblastoma in the other eye, and require frequent eye exams even after treatment. Doctors also recommend that all children with retinoblastoma continue to be checked for other cancers regularly for the rest of their lives.
Retinoblastoma often is diagnosed when a parent notices an eye change and brings his or her child to the doctor. The most common sign of retinoblastoma is an unusual whitish appearance of the affected pupil (a condition known as leukocoria). This condition is seen frequently in children with retinoblastoma, but it does not always indicate retinoblastoma. Children with retinoblastoma also may have a crossed eye (strabismus) that turns out toward the ear or in toward the nose. Strabismus, however, is a common condition and more likely to be noncancerous (benign). About 10 percent of children with retinoblastoma develop a persistent red irritation and inflammation of the eye. Other less common symptoms include differences in iris color and pupil size, tearing, cataract, or bulging of the eyes.
Newborns with a family history of retinoblastoma should be examined by an ophthalmologist before leaving the hospital. In most cases, however, the condition is diagnosed when parents notice an abnormality and bring the child in for examination.
An ophthalmologist confirms the presence of retinoblastoma through a dilated-pupil examination. This exam involves viewing the retina with an indirect ophthalmoscope to determine if a tumor exists. The indirect ophthalmoscope is different than the hand-held direct ophthalmoscope used by many physicians to look inside the eye. The instrument is worn on the head, has more magnifying lenses and allows the physician to see the entire retina more clearly. Most often, this exam is performed under general anesthesia so that the physician can look carefully at the child’s retina. Sketches or photographs of the view through the ophthalmoscope often are done to map the tumor.
An ultrasound, which uses sound waves to create an image of the internal structures in the eye, often is done to measure larger tumors that make it difficult to see inside the eye. Next, either computed tomography (CT) scans or magnetic resonance imaging (MRI) scans often are done to determine if cancer has spread outside of the eye, into the brain or to other parts of the body. A CT scan uses a rotating X-ray beam to produce detailed, cross-sectional images of the area. An MRI scan generates an image using magnetic waves. If cancer spread is seen, additional tests may be needed to confirm whether the cancer has spread to other parts of the body.
Retinoblastoma will continue to grow unless it is treated.
Because retinoblastoma may be hereditary, genetic counseling and testing is an important part of disease management. The American Cancer Society reports that patients who carry the gene for the disease have about an 80 percent chance of developing retinoblastoma and a 50 percent chance of passing the gene to a child. Therefore, all siblings and children of retinoblastoma patients should be examined every two to four months during the first years of life.
The type of treatment for retinoblastoma will depend upon whether the disease is in one or both eyes, the extent of the disease within the eye, whether vision can be saved, and whether the cancer has spread beyond the eye.
If the tumor is large, in one eye, and vision cannot be preserved, surgery may be performed to remove the whole eye (enucleation). This is a simple operation, and a child usually can be fitted with an artificial eye within about three to six weeks following surgery.
When tumors occur in one or both eyes and a chance exists of preserving vision in one or both eyes, more conservative treatments may be considered. radiation or chemotherapy may be used to shrink the tumors. Local treatments such as brachytherapy, photocoagulation and cryotherapy may then be used to eliminate the tumor and preserve vision.
- Radiation — This can be an effective treatment for some patients. Retinoblastoma is very sensitive to radiation. However, there are potential disadvantages. It can damage other tissues inside the eye, eventually leading to cataracts and damaging the retina. In addition, radiation can affect the growth of bone and other tissues near the eye and may increase the patient’s risk of developing other cancers. Two types of radiation may be used: external beam radiation, which uses radiation beams focused on the cancer from a source outside the body, and brachytherapy, which involves placing radioactive material into or very near the tumor.
- Photocoagulation — This uses lasers to destroy the tumor.
- Cryotherapy — This is the use of extreme cold to freeze and destroy cancer cells. Cryotherapy is used on small tumors. To be effective, it usually has to be performed several times. It is not used when there are several tumors.
- Chemotherapy — Chemotherapy involves an anticancer drug or a combination of drugs that usually are administered through an injection into a blood vessel. Retinoblastoma tends to resist chemotherapy, but it may be used effectively in combination with other treatments. For example, it may be used to shrink small tumors in order to increase the chances of success with photocoagulation, cryotherapy or brachytherapy. It is used commonly to treat a child whose tumor has spread beyond the eye. Chemotherapy also may be given to a child who does not have any detectable spread beyond the eye but whose cancer has grown extensively within the eye, indicating an increased risk for cancer spread.
When To Call A Professional
If you observe any abnormalities in your child’s eyes or vision, immediately take him or her to the doctor for an examination. Your pediatrician may refer you to an ophthalmologist specializing in pediatric eye disease.
Early diagnosis and treatment is crucial to preserving vision and preserving life. The outlook depends upon the extent of disease within and beyond the eye. Over the past 20 years, earlier detection and improved treatment methods have greatly enhanced the chances of maintaining vision, and have increased the survival rate. The American Cancer Society estimates that more than 90 percent of children treated for retinoblastoma survive more than five years. Children who still are cancer-free five years after diagnosis and treatment are generally considered cured. However, if left untreated, retinoblastoma is almost always fatal. Survivors have an increased risk of developing a second, unrelated cancer and need close follow-up.
Diseases and Conditions Center
All ArmMed Media material is provided for information only and is neither advice nor a substitute for proper medical care. Consult a qualified healthcare professional who understands your particular history for individual concerns.