Bile Duct Cancer

What Is Bile Duct Cancer?

The major function of the bile duct is to transport bile to the small intestine where it aids in digesting food. The bile duct is a thin tube, about 4 to 5 inches long, that reaches from the liver to the small intestine. In the liver, it begins as many small channels that gather bile from the liver cells. These all join into one tube or duct (this part of the bile duct is called the hepatic duct). About one third of the way along the length of the bile duct, the gallbladder attaches by a small duct called the cystic duct. The combined duct is called the common bile duct. The end of this part of the bile duct empties into the earliest part of the small intestine, next to where the pancreatic duct also enters the small intestine.

Cancers can develop in any part of the bile duct and, based on their location, are divided into 3 groups. About half of the cancers develop in the smaller bile duct branches inside the liver and are called intrahepatic (inside the liver) bile duct cancers. These can be confused with cancers that start in the liver cells and are called hepatic carcinomas. It is possible to tell these 2 types of tumors apart by looking at them under a microscope.

The next most common type of bile duct cancers is found in the common bile duct nearest the intestine. Doctors call these distal bile duct cancers.

The least common type is bile duct cancer that develops at the part of the hepatic duct where the bile ducts have joined and are just leaving the liver. Cancers that develop here are called perihilar cancers, or sometimes Klatskin tumors (named after the doctor who described them). Cancers beginning in these 3 different areas may cause different symptoms.

More than 95% of bile duct cancers are of the adenocarcinoma type. Adenocarcinomas are cancers of glandular cells that can develop in several organs of the body. Bile duct adenocarcinomas develop from the mucus glands that line the inside of the duct. Cholangiocarcinoma is another name for a bile duct adenocarcinoma. Today, most doctors use this term for all bile duct adenocarcinomas. In the past, doctors used this term only in describing intrahepatic or perihilar tumors, but not distal bile duct cancers.

Not all bile duct tumors are cancerous. Bile duct hamartomas and bile duct adenomas are benign (non-cancerous) tumors and, therefore, are not discussed further in this document. Hepatocellular carcinomas, which develop from liver cells, are more common than cholangiocarcinomas of bile duct cells. Hepatocellular carcinoma is discussed in more detail in the American Cancer Society document, Liver Cancer.

Adenocarcinomas that form in other organs, such as the pancreas, colon, rectum, stomach, lung, breast, or prostate, may spread through the bloodstream to the liver. These are called secondary liver cancers or liver metastases. Their prognosis and treatment are not the same as cholangiocarcinomas, and depend on where the cancer started.

What Are the Risk Factors for Bile Duct Cancer?

A risk factor is anything that increases your chance of getting a disease such as cancer. Different cancers have different risk factors. For example, unprotected exposure to strong sunlight is a risk factor for skin cancer and smoking is a risk factor for cancers of the lung, larynx, colon, as well as many other organs. Researchers have identified several risk factors that increase a person's chance of developing bile duct cancer.

Disease of the bile ducts: People who have chronic (long-standing) inflammation of the bile duct have an increased risk of developing bile duct cancer. Sometimes this inflammation occurs for no known reason and is called sclerosing cholangitis. Cholangitis is the medical term for bile duct inflammation. Sclerosing cholangitis means that the bile duct inflammation leads to scar tissue formation.

Ulcerative colitis is a condition that results in inflammation of the large intestine. Some people with ulcerative colitis also develop sclerosing cholangitis and are at increased risk of developing bile duct cancer.

Stones in the bile duct, similar to, but much smaller than gallstones can also cause inflammation that increases the risk of developing bile duct cancer.

There are several other diseases of the liver and bile duct that increase the risk of developing bile duct cancer. These include polcystic liver disease, choledochal cysts, congenital dilation of the intrahepatic bile ducts (also known as Caroli syndrome), and cirrhosis (damage to liver tissue that causes scar tissue formation in the liver). Cirrhosis due to long-standing sclerosing cholangitis is more likely to lead to bile duct cancer than cirrhosis from other causes. On the other hand, cirrhosis caused by long-standing viral hepatitis has a greater impact on a person's risk of developing hepatocellular cancer.

In Asian countries, infection by liver flukes, food- or water-borne parasites that invade the bile duct, is a major cause of bile duct cancer. There are several types of liver flukes. The ones most closely related to bile duct cancer risk are called Clonorchis sinensis and Opisthorchis viverrini.

Aging: As in most cancers, older people are more likely to get bile duct cancer. More than 70% of patients with bile duct cancer are older than age 65.

Obesity: Obesity: Being overweight can increase the risk of developing cancers of the gallbladder and bile ducts. A big part of this association is that obesity increases the risk of developing gallstones and bile duct stones. However, there may be other ways that being overweight can lead to bile duct cancers, such as changes in certain hormones.

Family history: Although most bile duct cancers develop in people without a strong family history of this disease, this type of cancer is more common in some families. Bile duct cancer is also associated with inherited conditions (hereditary nonpolyposis colon cancer and familial adenomatous polyposis) that can increase the risk of colorectal cancer.

Other factors: A substance called Thorotrast (thorium dioxide), which was used as a contrast agent in x-ray diagnosis many years ago, can lead to bile duct cancer, as well as to other types of liver cancer (hepatocellular cancer and angiosarcoma). For this reason, Thorotrast is no longer used. Other radioactive chemicals also can be a risk factor. Other chemicals that may cause this cancer include dioxin, nitrosamines, and polychlorinated biphenyls (PCBs). Smoking may increase the bile duct cancer rate in people with sclerosing cholangitis.

Viral hepatitis: Infection with either hepatitis B or hepatitis C virus has been linked to intrahepatic cholangiocarcinoma. In a US study, the risk was about 6 times greater than normal in people infected with hepatitis C virus.

Non-viral cirrhosis: This is inflammation and scarring that occurs in the liver due to irritants such as alcohol. A recent study found this to be a risk factor for intrahepatic cholangiocarcinoma.

Can Bile Duct Cancer Be Found Early?

Screening

Screening refers to tests and exams used to detect a disease, such as cancer, in people who do not have any symptoms. The American Cancer Society has official recommendations for use of screening tests to find several types of cancer as early as possible. Currently no screening tests have been identified that can find bile duct cancer early. Therefore, the American Cancer Society has no specific recommendations for the early detection of bile duct cancer.

How Is Bile Duct Cancer Treated?

This information represents the views of the doctors and nurses serving on the American Cancer Society's Cancer Information Database Editorial Board. These views are based on their interpretation of studies published in medical journals, as well as their own professional experience.

The treatment information in this document is not official policy of the Society and is not intended as medical advice to replace the expertise and judgment of your cancer care team. It is intended to help you and your family make informed decisions, together with your doctor.

Your doctor may have reasons for suggesting a treatment plan different from these general treatment options. Don't hesitate to ask him or her questions about your treatment options.

This section begins with a summary of the types of treatments available to people with bile duct cancer. The usual treatments for bile duct cancers at each stage are then discussed.

The main type of treatment for bile duct cancer is surgery. Radiation therapy and chemotherapy may be used instead if the cancer cannot be entirely removed with surgery.

After the cancer has been found and staged, your doctor will recommend one or more treatment options. It is important to take time and think about all of the choices. You may want to ask for a second opinion. This can provide more information and help you feel more confident about the treatment plan you choose.