Below is an instruction from Human. Write a response.
    ### Instruction:
    What are the stages of Bile Duct Cancer (Cholangiocarcinoma) ?
    ### Response:
    Key Points
                    - The results of diagnostic and staging tests are used to find out if cancer cells have spread.    - There are three ways that cancer spreads in the body.    - Cancer may spread from where it began to other parts of the body.    - Stages are used to describe the different types of bile duct cancer.
    