Diagnosis and staging
How is retinoblastoma diagnosed?
In addition to a complete medical and physical examination, diagnostic procedures for retinoblastoma may include the following methods:
- Complete eye examination.
- Funduscopic examination – with the child under anesthesia, the pupils are dilated so the entire retina can be viewed and examined.
- Computed tomography scan (also called a CT or CAT scan) – a diagnostic imaging procedure that uses a combination of X-rays and computer technology to produce cross-sectional images (often called slices), both horizontally and vertically, of the body. A CT scan shows detailed images of any part of the body, including the bones, muscles, fat and organs. CT scans are more detailed than general X-rays.
- Magnetic resonance imaging – a diagnostic procedure that uses a combination of large magnets, radio frequencies and a computer to produce detailed images of organs and structures within the body.
- Blood tests.
- Tests of the fluid surrounding the tumor.
- Genetic and/or DNA testing.
A diagnosis may be made before symptoms are present. If a family history is positive for retinoblastoma, frequent eye examinations may be necessary at many stages of the child’s development to determine the presence of any tumor. When retinoblastoma is diagnosed, tests will be performed to determine the size, number, location of the tumors and if the tumors have spread to the other parts of the body. This step is called staging and is an important step toward planning a treatment program.
What are the stages of retinoblastoma?
There are various staging systems that can be used for retinoblastoma. Always consult your child’s physician for more information on staging. One method of staging is the Reese-Ellsworth stages of retinoblastoma:
- Group I – either one or more tumors that are less than 4 disc diameters (DD) in size and located at or behind the equator.*
- Group II – either one or more tumors that are 4 to 10 DD in size located at or behind the equator.
- Group III – any lesion in front of the equator or any tumor(s) larger than 10 DD.
- Group IV – multiple tumors with some or all greater than 10 DD in size or any lesions that extend beyond the back of the eye.
- Group V – very large tumors involving more than half of the retina and that have spread to other sites in the body.
* The “equator” is an imaginary line that divides the eye into two equal parts.