A Detailed Look at Bile Duct Cancer

Bile duct cancer is best caught early

biliary tract
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Bile is a liquid made by the liver and stored in the gallbladder. Bile helps break down the fats found in food. The bile duct connects the gallbladder and liver to the small intestine. The bile duct serves as a passage for bile to flow into the small intestine, where the bile helps digest food.

The biliary tract (or biliary system) refers to all the structures that make and store bile, including the bile ducts both inside and outside the liver and the gallbladder.

The bile ducts inside the liver are referred to as intrahepatic, and the bile ducts outside the liver are referred to as extrahepatic.

The two main types of biliary tract cancer are bile duct cancer (i.e., cholangiocarcinoma) and gallbladder cancer. If caught early, both gallbladder cancer and bile duct cancer can successfully be treated by removing these structures. However, most people who present with these cancers do so after the cancers have already spread, or metastasized. Both these cancers can metastasize to the liver, other parts of the abdominal cavity, or other parts of the body.

Let’s take a closer look at bile duct cancer. 

Statistics

According to the American Cancer Society, each year in the United States, at least 8000 people are diagnosed with bile duct cancer.  This number includes people diagnosed with intrahepatic bile duct cancer and extrahepatic bile duct cancer. Furthermore, although bile duct cancer can affect younger people, the average age of diagnosis for intrahepatic cancer is 70 and that of extrahepatic is 72.

The location of bile duct cancers can usually be classified in one of three ways:

  • Intrahepatic cancer: proximal tumors inside the liver
  • Perihilar cancer: central tumors located at the level of the liver where right and left hepatic ducts join to form the bile duct
  • Distal bile duct cancer: tumors located farthest away from the liver in the lower portion of the bile duct

    Perihilar tumors are the most common tumor type—accounting for about 65 percent of biliary tract cancers. Extrahepatic tumors account for 30 percent.  Intrahepatic tumors are least common and account for about five percent of tumors.

    Perihilar tumors are also called hilar tumors or Klatskin tumors. Perihilar and distal bile duct cancers are grouped together as extrahepatic cancers.

    Five-year survivals are the common metric used by physicians to describe cancer outlook, or prognosis. The five-year survival refers to the percentage of patients alive at least five years after diagnosis. The five-year survival rates for bile duct cancer are broken down by how far the cancer has spread—localized, regional, or distant—and whether the tumor is intrahepatic or extrahepatic.

    Here are the five-year survival rates for different types of intrahepatic cancer based on tumor spread:

    Localized15%
    Regional6%
    Distant2%

     

    Here are those for extrahepatic cancer:

    Localized30%
    Regional24%
    Distant2%

    Risk Factors

    A risk factor is anything that increases your risk of cancer. Different types of cancer have different risk factors.

    There are several diseases of the liver that serve as risk factors for bile duct cancer:

    • Primary sclerosing cholangitis
    • Cirrhosis
    • Bile duct stones
    • Choledochal cysts
    • Hepatitis B
    • Hepatitis C
    • Ulcerative cholitis
    • Crohn’s disease
    • Pancreatitis
    • HIV infection
    • Congenital anomalies of the pancreatic or bile duct
    • Polycystic liver disease

    Here are some other risk factors for bile duct cancer:

    • Family history
    • Older age
    • Ethnicity (e.g., Hispanic, Native American, and Asian)
    • Obesity
    • Diabetes
    • Smoking
    • Pancreatitis

    Please keep in mind that certain risk factors are modifiable; whereas, others are non-modifiable. Modifiable risk factors can be changed—you can do something to change them. For instance, smoking and obesity are modifiable because a person can stop smoking or lose weight, respectively.

    Furthermore, the risk of certain infections can be modified, too. For instance, there is a vaccination for hepatitis B. Non-modifiable risk factors, such as age and family history, can't be changed. 

    If you're interested in decreasing your risk factors for cancer and other diseases, please discuss these options with your physician. There are many things that you can do to promote a healthy lifestyle.

    Signs and Symptoms of Biliary Tract Cancer

    Biliary tract cancer presents as jaundice, itchy skin (i.e., pruritis), and weight loss. When a patient presents with these signs and symptoms, blood chemistry tests and tumor marker tests are done to look for higher levels of certain substances in blood.

    High levels of alkaline phosphatase and bilirubin assessed during the blood chemistry test suggest bile duct dysfunction. Furthermore, bile duct cancer can cause high levels of the tumor markers carcinoembryonic antigen (CEA), CA19-9, and CA-125.

    Based on results from the blood chemistry test and tumor marker tests, a specialist may order a biopsy of the bile duct to figure out whether it’s cancerous. Biopsy refers to the removal of a small amount of tissue for histological examination under the microscope.

    Treatment

    After a patient is diagnosed with biliary tract cancer, imaging (such as ultrasound and ERCP) is done to determine the stage, or spread, of the tumor and to delineate the tumor.

    Although most proximal bile duct tumors are inoperable, half of all distal bile duct tumors can be resected, or removed. For distal tumors, resection involves the pancreaticoduodenectomy or Whipple procedure. The Whipple procedure is an extensive and notoriously difficult surgery to perform that involves removal of the head of the pancreas, the gallbladder, the bile duct and the duodenum, which is the first part of the small intestine. The Whipple procedure is performed by a surgical oncologist.

    Unfortunately, even for patients who are candidates for resection and have the biliary tract removed, five-year survival rates are low: between 20 and 25 percent. For those patients who have inoperable cancer, survival can be measured in weeks or months.

    The sensitive location of the bile duct makes surgery tricky. Surgery is limited by how far the tumor has spread and its size. Tumors that have metastasized, or spread, are inoperable. Depending on the specific characteristics of the bile duct tumor, other surgeries can be performed including:

    • Partial hepatectomy (i.e., removal of part of the liver)
    • Surgical removal of the bile duct
    • Liver transplantation

    Systemic treatments for biliary tract cancer such as chemotherapy and radiotherapy offer little benefit. However, radiotherapy can be used to kill cancer cells that block the bile duct or press on nerves—a palliative therapy.

    Palliative therapy is administered to alleviate pain and control for symptoms of late disease. In addition to palliative radiotherapy, there are several other palliative care options.

    • Pain medications such as opioid drugs
    • Placement of a biliary stent or catheter to keep the bile duct open and control for jaundice
    • Biliary bypass in which the surgeon creates a bypass around the tumor blocking the bile duct
    • Tumor ablation which uses heat and electrical energy to kill cancer cells
    • Alcohol injections to deaden nerves that relay pain around the bile duct and small intestine
    • Photodynamic therapy uses a drug that’s sensitive to light of a specific wavelength to destroy cancer cells

    Biliary Tract Cancer vs. Liver Cell Carcinoma

    Although the biliary tract is intimately associated with the liver, cancers of the biliary tract are very different from those of the liver.

    As the name implies, liver cell carcinomas arise from liver cells, or hepatocytes. Biliary tract cancers arise from the epithelial cells of the biliary tract and are mostly adenocarcinomas. Adenocarcinomas refer to a malignant tumor originating in the glandular epithelium, or cells that line the bile duct.

    Put in other terms, although the biliary tract is anatomically close to the liver, they are made of different cell types. Tumors arise from these different cell types.

     Sources:

    American Cancer Society. What Is Bile Duct Cancer? www.cancer.org

    American Society of Clinical Oncology. Cancer.Net. Bile Duce Cancer (Cholangiocarcinoma) Introduction. www.cancer.net

    Carr BI. Tumors of the Liver and Biliary Tree. In: Kasper D, Fauci A, Hauser S, Longo D, Jameson J, Loscalzo J. eds. Harrison's Principles of Internal Medicine, 19e New York, NY: McGraw-Hill; 2014.

    Matheny SC, Long K, Roth J. Hepatobiliary Disorders. In: South-Paul JE, Matheny SC, Lewis EL. eds. CURRENT Diagnosis & Treatment: Family Medicine, 4e New York, NY: McGraw-Hill.

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