Retinoblastoma

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.

Symptoms

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.

Diagnosis

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.