Below is an instruction from Human. Write a response.
    ### Instruction:
    What are the stages of Retinoblastoma ?
    ### Response:
    Key Points
                    - 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.
    