After extrahepatic bile duct cancer has been diagnosed, tests are done to find out if cancer cells have spread within the bile duct or to other parts of the body.
The process used to find out if cancer has spread within the extrahepatic bile duct or to other parts of the body is called staging. The information gathered from the staging process determines the stage of the disease. It is important to know the stage in order to plan treatment.
Extrahepatic bile duct cancer may be staged following a laparotomy. A surgical incision is made in the wall of the abdomen to check the inside of the abdomen for signs of disease and to remove tissue and fluid for examination under a microscope. The results of the diagnostic imaging tests, laparotomy, and biopsy are viewed together to determine the stage of the cancer. Sometimes, a laparoscopy will be done before the laparotomy to see if the cancer has spread. If the cancer has spread and cannot be removed by surgery, the surgeon may decide not to do a laparotomy.
There are three ways that cancer spreads in the body.
The three ways that cancer spreads in the body are:
Through tissue. Cancer invades the surrounding normal tissue.
Through the lymph system. Cancer invades the lymph system and travels through the lymph vessels to other places in the body.
Through the blood. Cancer invades the veins and capillaries and travels through the blood to other places in the body.
When cancer cells break away from the primary (original) tumor and travel through the lymph or blood to other places in the body, another (secondary) tumor may form. This process is called metastasis. The secondary (metastatic) tumor is the same type of cancer as the primary tumor. For example, if breast cancer spreads to the bones, the cancer cells in the bones are actually breast cancer cells. The disease is metastatic breast cancer, not bone cancer.
There are two staging systems for extrahepatic bile duct cancer.
Extrahepatic bile duct cancer has two staging systems. The staging system used depends on where in the extrahepatic bile duct the cancer first formed.
Perihilar or proximal extrahepatic bile duct tumors (perihilar bile duct tumors) form in the area where the bile duct leaves the liver. This type of tumor is also called a Klatskin tumor.
Distal extrahepatic bile duct tumors (distal bile duct tumors) form in the area where the bile duct empties into the small intestine.