Final answer:
Carcinoid tumors arise from endocrine cells in the GI tract and the extent of metastasis depends on various factors such as tumor location, size, type and aggressiveness of the cells, and the effectiveness of the immune system in controlling the spread of cancer cells.
Step-by-step explanation:
Carcinoid tumors are the most common endocrine tumors of the GI tract and arise from endocrine cells.
The extent of metastasis, or the spread of tumors to other parts of the body, depends on several factors.
These factors include the location and size of the tumor, the type and aggressiveness of the cancer cells, and the effectiveness of the body's immune system in controlling the spread of cancer cells.