Understanding Biliary Tract Cancer

Biliary tract cancer is a group of rare cancers that start in the bile ducts. The bile ducts are tubes that carry bile through the body. Bile is a fluid that helps the body digest fat. Biliary tract cancer includes bile duct cancer (also known as cholangiocarcinoma) and gallbladder cancer.^1,2

Types of biliary tract cancer

Biliary tract cancer starts in the biliary system. This system includes the bile ducts and gallbladder. The bile ducts connect the liver, the gallbladder, and the small intestine. There are 3 main types of this cancer based on where it begins:^1,2

• Intrahepatic – This starts in the small bile ducts inside the liver.
• Perihilar – This starts where the right and left bile ducts join outside the liver.
• Distal – This starts in the bile ducts closest to the small intestine.

Gallbladder cancer is also a type of biliary tract cancer. Most of these cancers are adenocarcinomas. This means they start in the gland cells of the duct lining.³

How common is it?

Biliary tract cancer is rare in the United States. Doctors find about 13,000 new cases each year (about 8,000 bile duct cancer cases and about 5,000 gallbladder cancer cases). The true number of cases may be even higher. This is because this cancer is often hard to find and may be confused with other cancer types.⁴

Most people with this cancer are older. The average age of a person found to have this type of cancer is in their 70s. This disease is also more common in Southeast Asia. This is because liver flukes (a parasitic infection that can cause bile duct cancer) are more common in that area.⁴

Causes and risk factors

The exact cause of this cancer is often unknown. However, certain things can increase the risk. Chronic inflammation is a major risk factor. This can happen due to several conditions:^1,3,4

• Primary sclerosing cholangitis (PSC) – This is a disease that causes scarring in the bile ducts.
• Bile duct stones or cysts – These can cause long-term irritation.
• Chronic infections – Viruses like hepatitis B or C can increase risk.
• Liver fluke infections – These are parasites found in some parts of the world.

Other risk factors for biliary tract cancer include:^1,3

• Older age
• Chronic conditions like obesity, diabetes, and metabolic syndrome
• Smoking
• Certain inherited conditions, such as cystic fibrosis and Lynch syndrome

Signs and symptoms

Symptoms of biliary tract cancer often do not appear in the early stages. This is because the ducts are deep inside the body. When symptoms do happen, they may include:^1-3

• Jaundice – This is the yellowing of the skin and the whites of the eyes.
• Itchy skin – This happens when bile builds up in the blood.
• Abdominal pain – You may feel pain on the right side under the ribs.
• Changes in urine and stool – Urine may look dark, and stools may look pale or greasy.
• Unexplained weight loss – This often comes with a loss of appetite.

If you have these signs, you should talk to your doctor. These symptoms can also be caused by other conditions.

Prognosis and outlook

The outlook for biliary tract cancer – which includes both gallbladder and bile duct cancers – depends on how far the disease has spread at the time of diagnosis. When the cancer is localized, meaning it is confined to its original site and has not spread, the potential for a successful surgical cure is at its highest.^5-7

If the cancer is found in nearby tissues or lymph nodes, treatment becomes more complex. For distant cases where the cancer has spread to other organs, the focus often shifts toward controlling the disease and maintaining quality of life. Because these cancers are often deep within the body, early detection remains the most critical factor in getting a favorable long-term prognosis.^5-7

Recent medical advances are helping people live longer. Treatment now often includes immunotherapy drugs combined with traditional chemotherapy, which has been shown to extend survival in advanced cases. Targeted therapy has also led to more precise treatment approaches.^5-7

But each person's situation is different. Your medical team can help you understand your specific prognosis.^5-7

Speak with your doctor

Biliary tract cancer is a complex and rare condition. It affects the bile ducts and the gallbladder. Finding the cancer early is the best way to improve the outlook.¹

Knowing the risks and signs can help you seek care quickly. Research is ongoing to find better ways to treat this disease. If you have concerns, speak with your healthcare provider to learn more about your health.^5-7