A diagnosis of retinoblastoma is made by examining the eyes. A white pupil or strabismus (crossed eyes) will usually be noticed by a parent or pediatrician. Because this disease is relatively rare, children are typically referred to a special ophthalmologist who is familiar with the treatment of retinoblastoma. The child may need to be examined under general anesthesia to define the extent of the tumor in the eye(s) and to record the information in photographs or diagrams. The specialist may also use additional tests to detect tumors. The following tests are commonly used to provide the specialist with a picture of the inside of the eye and the brain:
Children diagnosed with retinoblastoma will require a complete physical examination. If there are any symptoms or abnormal findings, the child may also need additional tests to see if the cancer has spread to other parts of the body. Tests that may be performed include:
Children and families may also be referred for genetic testing and counseling.
After retinoblastoma has been detected, the doctor will determine the extent of disease in the eye and the presence of disease outside of the eye. This is called staging, and it helps the doctors plan the appropriate treatment. Two staging systems are used for retinoblastoma, one for assessing the amount of disease inside of the eye which correlates with the probability of saving the eye and vision, and another system that evaluates the presence of disease outside of the eye. For staging the eye, the International Classification for Intraocular Retinoblastoma is used. This classification system uses a letter (A-E) to signify the extent of the disease; the more extensive the child’s disease, the higher the class. This designation will determine the treatment that will most effectively cure the cancer and preserve the child’s sight.
- Small tumors (less than 3 mm) that are confined to the retina and more than 3 mm away from the foveola and more than 1.5 mm away from the optic disk
- Tumors larger than 3 mm that are confined to the retina in any location
- Clear subretinal fluid less than 6 mm from the tumor margin