More than one in ten liver cancer patients has a type called cholangiocarcinoma, or cancer of the bile ducts, though there are only estimated to be about 3,000 cases per year in the United States. Bile duct cancer is particularly prevalent in northeastern Thailand due to the common diet—the local fish, often eaten raw, are carriers of a parasite called liver fluke, which is related to cancerous conditions—but it can happen anywhere, and the prognosis is typically rather grim. The bile duct is responsible for draining the liver, taking the toxins that the liver removes from the blood and moving them to where they need to be to be eliminated from the body. Bile is also an important part of the digestive process, breaking down fats in the intestine.
Bile duct cancer often strikes people who have had other illnesses in the area. Forms of ulcerative colitis are common culprits. Liver flukes are parasites; infestation leads to recurrent infections, disease, and liver damage, and that damage opens the door to cancer forming. People who suffer from some kind of chronic liver disease, including some types of hepatitis and cirrhosis of the liver, also have a higher risk of cholangiocarcinoma., and certain inherited genetic conditions are the same. In fact, recently scientists found genes that are specifically associated with cancer development in the bile duct.
As with any condition that blocks the bile duct, cholangiocarcinoma can lead to a yellowing of the skin known as jaundice. The blockage backs up bile in the body, coloring the skin, darkening the urine, and causing stool to be lighter in color. The bilirubin normally responsible for the color of stool will, if the bile duct is blocked, wind up in the urine instead. However, there are not always symptoms in the early stages. Other symptoms may include itching and abdominal pain, as well as the fever and weight loss that accompany a wide variety of medical conditions.
If the tumor is small, it may be possible for it to be surgically removed, though this is a difficult procedure. When surgery is not likely to be safe or effective, a stent may be used to bypass the blockage and restore some semblance of normal functioning. Radiation therapy and chemotherapy may also be used, though mostly for palliative purposes if a complete cure is deemed unlikely.