What Causes of Bile Duct Cancer

Bile duct cancer, also known as cholangiocarcinoma, happens when cells in the bile ducts develop changes in their DNA. A cell’s DNA contains the instructions that tell a cell what to do. The changes tell the cells to multiply out of control and form a mass of cells (tumor) that can invade and destroy healthy body tissue. It’s not clear what causes the changes that lead to cholangiocarcinoma, but there are several risk factors that have been identified. These include:

  • Primary sclerosing cholangitis. This disease causes hardening and scarring of the bile ducts.
  • Chronic liver disease. Scarring of the liver caused by a history of chronic liver disease increases the risk of cholangiocarcinoma.
  • Bile duct problems present at birth. People born with a choledochal cyst, which causes dilated and irregular bile ducts, have an increased risk of cholangiocarcinoma.
  • A liver parasite. In areas of Southeast Asia, cholangiocarcinoma is associated with liver fluke infection, which can occur from eating raw or undercooked fish.
  • Older age. Cholangiocarcinoma occurs most often in adults over age 50.
  • Smoking. Smoking is associated with an increased risk of cholangiocarcinoma.
  • Exposure to hazardous chemicals. Exposure to certain chemicals have been linked to an increased risk of bile duct cancer. These include dioxins, nitrosamines, polychlorinated biphenyls (PCBs), asbestos, radon and thorotrast (thorium dioxide, a radioactive substance previously used as a contrast agent for certain X-rays).
  • Obesity. Being obese may increase the risk of some cancers, including bile duct and liver cancer.
  • Diabetes. People who have type 1 or 2 diabetes may have an increased risk of cholangiocarcinoma.
  • Certain inherited conditions. Some DNA changes passed from parents to children cause conditions that increase the risk of cholangiocarcinoma. Examples of these conditions include cystic fibrosis and Lynch syndrome.
  • Being male. Men are more likely to develop bile duct cancer than women.

It is important to note that having one or more of these risk factors does not necessarily mean that you will develop bile duct cancer. It is always important to speak with a healthcare professional if you have concerns about your risk of developing this or any other type of cancer.