People who have chronic (long-standing) inflammation of the bile ducts have an increased risk of developing bile duct cancer. Smaller stones that form in the bile ducts (bile duct stones) or pass into them from the gallbladder (gallstones) can lead to this type of chronic inflammation. Other inflammatory conditions can increase the risk of developing bile duct cancer:

Ulcerative Colitis

Ulcerative colitis is an inflammation of the large intestine. It is often associated with inflammation of the bile ducts, which is called primary sclerosing cholangitis. Ulcerative colitis can progress to cancer, particularly in people exposed to carcinogens, such as cigarette smoke.

Biliary Parasites

Although rarely seen in the United States, food- or water-borne parasites that live in the bile ducts are common in Asia and raise the risk of developing bile duct cancer.

Congenital Bile Duct Cysts (Choledochal Cysts)

These bile-filled sacs are connected to the common bile duct. Congenital bile duct cysts are typically diagnosed in childhood. The lining of these sacs often contains precancerous cells that increase the risk of developing cancer later in life.

Chronic Hepatitis C

This inflammatory disease is a risk factor for cancer of the intrahepatic bile ducts. Chronic (long-standing) hepatitis C is also the most common risk factor for liver cancer. Read more about liver cancer risk factors here.

Smoking

Studies have suggested that intrahepatic bile duct cancer is more common among heavy smokers.

Age

Bile duct cancer occurs most often in older people. The average age of diagnosis in the United States is 72.

Diabetes

Diabetes can slightly raise the risk for intrahepatic bile duct cancer.