Risk Factors

Abnormalities where the bile duct and pancreatic duct meet

can allow digestive juices from the pancreas to reflux (flow back “upstream”) into the bile ducts. This backward flow also prevents the bile from being emptied through the bile ducts as quickly as normal. People with these abnormalities are at higher risk of cholangiocarcinoma.

Aging

older people are more likely than younger people to get cholangiocarcinoma. More than 2 out of 3 people are older than age 65.

Alcohol

people who drink alcohol are more likely to get intrahepatic cholangiocarcinoma.       The risk is higher in those that have liver problems from drinking alcohol.

Bile Duct Stones

similar to, but much smaller than gallstones, can also cause inflammation that increases the risk of cholangiocarcinoma.

Choledochal Cysts

bile-filled sacs that are connected to the bile duct. The cells lining the sac often have areas of pre-cancerous changes, which increase a person’s risk for developing cholangiocarcinoma.

Cirrhosis

damage to the liver from irritants such as alcohol and diseases such as hepatitis that cause scar tissue to form. Studies have found it raises the risk of cholangiocarcinoma. Other rare diseases of the liver and bile duct that may increase the risk of developing cholangiocarcinoma include polycystic liver disease and Caroli syndrome (a dilation of the intrahepatic bile ducts that is present at birth).

Diabetes

when taken together, the data from many different studies show that people with diabetes have a higher risk of cholangiocarcinoma. This increase of risk is not high, and the overall risk of cholangiocarcinoma in someone with diabetes is low.

Family history

A history of cholangiocarcinoma in the family seems to increase a person’s chances of developing this cancer, but the risk is still low because this is a rare disease. Most cholangiocarcinomas are not found in people with a family history of the disease.

Inflammatory Bowel Disease

includes ulcerative colitis and Crohn’s disease. People with these diseases have an increased risk of cholangiocarcinoma.

Liver Fluke Infections

occur in some Asian countries when people eat raw or poorly cooked fish that are infected with these tiny parasite worms. In humans, these flukes live in the bile ducts and can cause cholangiocarcinoma. There are several types of liver flukes. The ones most closely related to cholangiocarcinoma risk are called Clonorchis sinensis and Opisthorchis viverrini. Liver fluke infection is rare in the US, but can affect people who travel to Asia.

Obesity

being overweight or obese can increase the risk of developing cancers of the gallbladder and bile ducts. This could be because obesity increases the risk of gallstones and bile duct stones. But there may be other ways that being overweight can lead to cholangiocarcinoma such as changes in certain hormones.

Primary Sclerosing Cholangitis

condition in which inflammation of the bile duct (cholangitis) leads to the formation of scar tissue (sclerosis) and an increased risk of cholangiocarcinoma. The cause of the inflammation is not usually known. Many people with this disease also have inflammation of the large intestine called ulcerative colitis.

Thorotrast

a radioactive substance called Thorotrast (thorium dioxide) was used as a contrast agent for x-rays until the 1950s and can lead to cholangiocarcinoma, as well as to some types of liver cancer. This is why Thorotrast is no longer used.

Viral Hepatitis

Long term infection with either hepatitis B virus or hepatitis C virus increases the risk of intrahepatic cholangiocarcinoma.       This may be at least in part due to the fact that infections with these viruses can also lead to cirrhosis.

Other possible risk factors

studies have found several other risk factors that might increase the risk of cholangiocarcinoma, but the link between these risk factors and cholangiocarcinoma is not as clear. They include:

  • Smoking
  • Pancreatitis (inflammation of the pancreas)
  • Infection with HIV
  • Exposure to asbestos
  • Exposure to radon or other radioactive chemicals
  • Exposure to dioxin, nitrosamines, or polychlorinated biphenyls (PCBs)

Adapted from National Institutes of Health: http://www.cancer.gov/