Biliary tract cancer affects the bile ducts. Bile ducts are a network of tubes that connect the liver and the gallbladder to the small intestine. They carry bile to the small intestine to help with digestion.
Bile duct cancer is another name for biliary tract cancer. The medical name for it is cholangiocarcinoma.
The two main types of bile duct cancer include:
- Intrahepatic: This forms inside the liver in the bile ducts that carry bile out of this organ.
- Extrahepatic: This forms outside the liver in bile ducts that are closer to the small intestine.
Extrahepatic bile duct cancer is much more common than the intrahepatic kind. There are two types of extrahepatic bile duct cancer:
- Perihilar: This forms outside the liver, where two bile ducts from the liver join to make a duct called the common hepatic duct. Klatskin tumor is another name for this kind of bile duct cancer.
- Distal: This forms where the common hepatic duct joins a bile duct coming from the gallbladder to make a duct called the common bile duct.
Diagnosis of biliary tract cancer
Most of the time, bile duct cancer is already advanced when doctors find it. This means it has usually spread at the time of diagnosis.
It’s hard to find it early because you can’t feel the tumors and there is no screening test for bile duct cancer.
If you have symptoms that could be bile duct cancer, such as dark urine, loss of appetite, itching, and abdominal pain, your doctor will likely recommend testing that may include:
Blood tests are lab tests your doctor may order to check:
- liver and gallbladder function tests
- tumor markers, which are substances that cancer cells make
Imaging exams your doctor may order include:
- Ultrasound: It uses sound waves to take pictures inside the body.
- CT scan: This uses X-rays to make detailed pictures of body structures.
- MRI scan: Uses strong magnets and radio waves to make detailed pictures of soft tissues.
Specialized imaging exams
These specialized imaging tests can closely examine blood vessels and bile ducts:
- Angiography: Looks at the blood vessels using X-ray, CT scanning, or MRI scanning.
- Cholangiography: Looks at the bile ducts using MRI scanning, X-ray, or an endoscope (a flexible, lighted tube).
However, the only way to know for sure whether something is cancer is to do a biopsy and take a tissue sample.
Stages of biliary tract cancer
As part of the diagnostic process, doctors will stage bile duct cancer. A cancer’s stage refers to how much cancer is in the body. Doctors use it to describe how advanced the cancer is. They also use it to plan treatment.
In describing the extent of cancer, doctors use the TNM (tumor, nodes, metastasis) system. They look at the size and number of tumors, spread to lymph nodes, and spread to other areas.
Then, doctors assign the cancer to a stage using Roman numerals I-IV.
In general, stages I and II are early cancers. Stages III and IV are late-stage or advanced cancers that usually have begun to spread to lymph nodes or other areas. For bile duct cancers, there is a TNM system for each type of cancer.
However, when doctors talk about treating bile duct cancers, they use a simpler system with two categories:
- Resectables: These are cancers that can be completely removed by surgery.
- Unresectable: These are cancers that cannot be completely removed.
At the time of diagnosis, most people have bile duct cancer that doctors cannot completely remove. This typically means the bile duct cancer is stage III or IV and has already spread. The most common places for it to spread is into the liver, lymph nodes, or other organs in the belly.
Treatment of biliary tract cancer
If bile duct cancer is resectable, doctors will use surgery with chemotherapy or radiation therapy to lower the risk of developing cancer cells in the future.
For unresectable bile duct cancer, surgery may still be part of the treatment. It can help relieve symptoms in some cases. Other standard cancer treatments that can help treat advanced bile duct cancer include:
- chemotherapy
- external or internal radiation therapy
- immunotherapy
- targeted therapy
Immunotherapy drugs help the immune system fight cancer. Targeted therapy involves drugs that target certain proteins or changes in cancer cells.
As researchers continue to study how bile duct cancer progresses, immunotherapy and targeted therapy will play an important role in treatment.
They are finding different molecules and pathways that they can target — these targets may influence outlook and progression.