Bile duct cancer is relatively uncommon in the United States. About 10,000 cases are diagnosed each year, mostly in people over the age of 70. Since most bile duct cancers are diagnosed in more advanced stages, the current five-year survival rate is only 10% to 30%, depending upon the type of cancer.
The bile ducts are a tree-like structure of vessels within and around the liver and gallbladder. They carry a thick fluid called bile, which is secreted by the liver. The bile ducts move bile into the upper part of the small intestine (duodenum) to aid in digesting food.
Bile Duct Cancer Types
Intrahepatic bile duct cancer occurs in the bile ducts that are within the liver. It is often misdiagnosed as liver cancer. Although uncommon, the incidence of intrahepatic bile duct cancer is increasing.
Extrahepatic bile duct cancers occur in bile ducts outside the liver. There are three types of extrahepatic bile duct cancers:
Perihilar bile duct cancer is the most common type. It occurs at the junction where the bile ducts exit the liver. These tumors account for 40 to 60% of all bile duct cancer cases. Twenty to 30% originate in the lower bile duct, and about 10% arise in bile ducts within the liver. This disease is sometimes called hilar cancer or Klatskin tumors.
Distal bile duct cancer arises near the small intestine, at the farthest reach of the bile ducts.
Gallbladder cancer arises in the wall of the gallbladder.
Bile Duct Cancer Risk Factors
There are several medical conditions that increase the risk for bile duct cancer, which is typically found in the older population.
Risk factors include:
- Diseases of the liver, including cirrhosis, bile duct stones and cholangitis
- Age: Most cases in the United States are diagnosed in men and women over the age of 70
- Hepatitis B or hepatitis C infection
- Inflammatory bowel diseases, including Crohn’s disease and ulcerative colitis
- Ethnicity: Bile duct cancer is much more common in Asian countries, where a liver parasite is common. In the U.S., Native Americans and Hispanics are more likely to get bile duct cancers.
- Excessive consumption of alcohol increases the risk of bile duct cancer, especially among people who have alcohol-associated liver damage.