What is biliary tract cancer?

Biliary tract cancer is a type of cancer that forms in the cells anywhere in the biliary tract.

The biliary tract includes the organs and ducts that make and store bile in the gallbladder. The bile is then released through the bile ducts into the small intestine. Bile is the yellow-greenish fluid made by the liver that helps you digest fat. The biliary tract is sometimes called the biliary tree because it has a few "branches." The branches include:

• The gallbladder, a small, pear-shaped pouch in the upper abdomen that stores bile, which is made in the liver. The gallbladder releases bile when you eat.
• The bile ducts, a network of tubes inside and outside the liver that carry bile from the liver and gallbladder to the small intestine.
• The ampulla of Vater, where bile ducts from the liver and pancreas meet and enter the small intestine.

• Gallbladder cancer, which starts in the cells of the gallbladder.
• Bile duct cancer, called cholangiocarcinoma, which is classified according to which part of the bile ducts are affected:
  • Intrahepatic cholangiocarcinoma, which affects bile ducts inside the liver.
  • Extrahepatic or distal cholangiocarcinoma, which affects the common bile duct outside the liver.
  • Hilar cholangiocarcinoma, which forms where the left and right hepatic ducts join in the shape of a Y.
• Ampullary cancer, which develops in the ampulla of Vater.

Biliary tract cancer often doesn't cause any symptoms in the early stages. It's often discovered by accident — for example, through routine blood tests or imaging done for an unrelated reason.

By the time symptoms occur, biliary tract cancer is often in advanced stages. And because some symptoms are common with other conditions, they may go unnoticed. Symptoms of biliary tract cancers may include:

• Yellowing of the skin and the whites of the eyes, called jaundice.
• Intensely itchy skin.
• White-colored stools.
• Fatigue.
• Belly pain on the right side, just below the ribs.
• Losing weight without trying.
• Fever.
• Night sweats.
• Dark urine.
• A general sense of not feeling well, called malaise.

Biliary tract cancers are rare. They account for less than 1% of all types of cancer. These cancers are usually diagnosed between the ages of 60 and 70. Gallbladder cancer is the most common type. It accounts for 80% to 90% of all biliary tract cancers.

The exact cause of biliary tract cancer is unknown. But there are some known risk factors for each type. It's important to remember that having a risk factor for biliary tract cancer does not necessarily mean you'll get cancer.