Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Carcinoid Tumors ?
    ### Response:
    Carcinoid tumors are rare, slow-growing cancers. They usually start in the lining of the digestive tract or in the lungs. They grow slowly and don't produce symptoms in the early stages. As a result, the average age of people diagnosed with digestive or lung carcinoids is about 60.
    