Stages of Retinoblastoma
Key Points for This Section
- After retinoblastoma has been diagnosed, tests are done to find out if cancer cells have spread within the eye or to other parts of the body.
- The International Retinoblastoma Staging System (IRSS) may be used for staging retinoblastoma.
- Treatment for retinoblastoma depends on whether it is intraocular (within the eye) or extraocular (outside the eye).
- There are three ways that cancer spreads in the body.
- Cancer may spread from where it began to other parts of the body.
The process used to find out if cancer has spread within the eye or to other parts of the body is called staging. The information gathered from the staging process determines the stage of the disease. It is important to know the stage in order to plan treatment.
The following tests and procedures may be used in the staging process:
- Eye exam with dilated pupil : An exam of the eye in which the pupil is dilated (opened wider) with medicated eye drops to allow the doctor to look through the lens and pupil to the retina. The inside of the eye, including the retina and the optic nerve, is examined using a light. Depending on the age of the child, this exam may be done under anesthesia.
- Ultrasound exam: A procedure in which high-energy sound waves (ultrasound) are bounced off internal tissues or organs and make echoes. The echoes form a picture of body tissues called a sonogram.
- CT scan (CAT scan): A procedure that makes a series of detailed pictures of areas inside the body taken from different angles. The pictures are made by a computer linked to an x-ray machine. A dye may be injected into a vein or swallowed to help the organs or tissues show up more clearly. This procedure is also called computed tomography, computerized tomography, or computerized axial tomography.
- MRI (magnetic resonance imaging): A procedure that uses a magnet, radio waves, and a computer to make a series of detailed pictures of areas inside the body. This procedure is also called nuclear magnetic resonance imaging (NMRI).
- Bone scan : A procedure to check if there are rapidly dividing cells, such as cancer cells, in the bone. A very small amount of radioactive material is injected into a vein and travels through the bloodstream. The radioactive material collects in the bones and is detected by a scanner that also takes a picture of the body. Areas of bone with cancer show up brighter in the picture because they take up more radioactive material than normal bone cells do.
- Bone marrow aspiration and biopsy : The removal of bone marrow and a small piece of bone by inserting a hollow needle into the hipbone or breastbone. A pathologist views the bone marrow under a microscope to look for signs of cancer. A bone marrow aspiration and biopsy is done if it is thought the cancer has spread outside of the eye.
Stage III is divided into stages IIIa and IIIb:
- In stage IIIa, cancer has spread to tissues around the eye socket.
- In stage IIIb, cancer has spread to lymph nodes near the ear or in the neck.
Stage IV is divided into stages IVa and IVb:
- In stage IVa, cancer has spread to the blood but not to the brain or spinal cord. There are one or more tumors.
- In stage IVb, cancer has spread to the brain or spinal cord. It may have spread to other parts of the body as well.
In intraocular retinoblastoma, cancer is found in the eye and may be only in the retina or may also be in other parts of the eye such as the choroid, ciliary body, or part of the optic nerve. Cancer has not spread to tissues around the outside of the eye or to other parts of the body.
In extraocular retinoblastoma, cancer has spread beyond the eye. It may be found in tissues around the eye (orbital retinoblastoma) or it may have spread to the central nervous system (brain and spinal cord) or to other parts of the body such as the bone marrow or lymph nodes.
- Tissue. The cancer spreads from where it began by growing into nearby areas.
- Lymph system. The cancer spreads from where it began by getting into the lymph system. The cancer travels through the lymph vessels to other parts of the body.
- Blood. The cancer spreads from where it began by getting into the blood. The cancer travels through the blood vessels to other parts of the body.
- Lymph system. The cancer gets into the lymph system, travels through the lymph vessels, and forms a tumor (metastatic tumor) in another part of the body.
- Blood. The cancer gets into the blood, travels through the blood vessels, and forms a tumor (metastatic tumor) in another part of the body.
The metastatic tumor is the same type of cancer as the primary tumor. For example, if retinoblastoma spreads to the bone, the cancer cells in the bone are actually retinoblastoma cells. The disease is metastatic retinoblastoma, not bone cancer.