Many cancer deaths are caused when cancer moves from the original tumor and spreads to other tissues and organs. This is called metastatic cancer. This animation shows how cancer cells travel from the place in the body where they first formed to other parts of the body.
The results of diagnostic and staging tests are used to find out if cancer cells have spread.
The process used to find out if cancer has spread to other parts of the body is called staging. For bile duct cancer, the information gathered from tests and procedures is used to plan treatment, including whether the tumor can be removed by surgery.
There are three ways that cancer spreads in the body.
Cancer can spread through tissue, the lymph system, and the blood:
- Tissue. Cancer spreads from where it began by growing into nearby areas.
- Lymph system. Cancer spreads from where it began by getting into the lymph system. 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.
Cancer may spread from where it began to other parts of the body.
When cancer spreads to another part of the body, it is called metastasis. Cancer cells break away from where they began (the primary tumor) and travel through the lymph system or blood.
- Lymph system. Cancer gets into the lymph system, travels through the lymph vessels, and forms a tumor (metastatic tumor) in another part of the body.
- Blood. 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 bile duct cancer spreads to the liver, the cancer cells in the liver are actually bile duct cancer cells. The disease is metastatic bile duct cancer, not liver cancer.