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Bile Duct Cancer: Introduction

What is cancer?

Cancer is when cells in the body change and grow out of control. To help understand what happens when you have cancer, look at how your body works normally. Your body is made up of tiny building blocks called cells. Normal cells grow when your body needs them, and die when your body does not need them any longer.

Cancer is made up of abnormal cells that grow even though your body doesn’t need them. In most cancers, the abnormal cells grow to form a lump or mass called a tumor. If cancer cells are in the body long enough, they can grow into (invade) nearby areas. They can even spread to other parts of the body (metastasis).

What are bile ducts?

The bile ducts are thin tubes that go from the liver and gallbladder to the small intestine. The ducts carry bile. Bile is a fluid made in the liver that breaks down fats during digestion. When the liver secretes bile, it is then stored by the gallbladder. During meals, the gallbladder releases bile into the common bile duct to help with the digestion of food in the intestines. Two areas of the bile duct system are involved in this process:

  • Intrahepatic bile ducts. This is part of the bile duct system inside the liver. It’s a network of many small tubes inside the liver that collect bile from liver cells. These join into right and left larger hepatic ducts that then exit the liver and join the common bile duct.

  • Extrahepatic bile ducts. These are the parts of the bile duct system that are outside the liver. After exiting the liver, the right and left hepatic ducts join together in an area called the hilum to form the common hepatic duct. The duct draining the gallbladder--called the cystic duct--then merges with the common hepatic duct to form the common bile duct. The common bile duct then empties into the first part of the small intestine. 

What is bile duct cancer?

Bile duct cancer can grow in any part of the bile ducts. Another term for bile duct cancer is cholangiocarcinoma. This cancer is grouped by different types depending on where it starts. Each type can cause different symptoms. The types are:

  • Perihilar (hilar) bile duct cancers. These grow in the hilum, where the main right and left bile ducts join as they are leaving the liver. Most bile duct cancers start here.

  • Intrahepatic bile duct cancers. These grow in the tiny bile ducts inside the liver. Only a small number of bile duct cancers are this type.

  • Distal bile duct cancers. These typically grow in the common bile duct near the first part of the small intestine.

Talk with your healthcare provider

If you have questions about bile duct cancer, talk with your healthcare provider. Your healthcare provider can help you understand more about this cancer.