Bile duct cancer develops in the bile duct. The disease may occur at any age, but people over 60 years of age are at increased risk. It is important to consult the doctor if the patient experiences any symptoms, as bile duct carcinoma diagnosed at an advanced stage is difficult to treat.
Bile duct cancer, or bile duct carcinoma, initiates in the bile duct. Bile ducts are tube-like structures that carry the bile from the liver and gallbladder into the digestive system (small intestine). There are several types of bile duct tumors. However, not all of them are cancerous. Bile duct adenomas and bile duct hamartomas are non-cancerous. Almost all bile duct cancers are cholangiocarcinomas, and thus, the term can be used as a synonym for this cancer type. Cholangiocarcinoma is a type of adenocarcinoma, and it begins in the glandular cells. These glandular cells line the inner layer of the bile duct.
The incidence and mortality of bile duct carcinoma vary depending on geographical regions, gender, and types of bile duct carcinoma. A few studies have reported the highest incidence in Chile and the lowest in Vietnam. Most countries have had a trend of increasing incidence rates in recent times. Patients aged 75 years or older have 5 to 10 times higher mortality rates compared to the overall mortality rate. Males have a higher incidence and mortality rate for extrahepatic cholangiocarcinoma, ampulla of Vater cancer, and intrahepatic cholangiocarcinoma.
Depending on the site of origin, bile duct carcinoma is classified into various types. Following are the various bile duct cancer types:
Intrahepatic cholangiocarcinoma is the second most common type of cancer arising from the liver, after hepatocellular carcinoma. ICC accounts for almost 10% of all bile duct cancer types. Only about 15% of the ICC tumors are resectable, and the patients have a median survival period of three years.
ECC develops outside the liver. ECC may develop at the perihilar and distal anatomical sites in the bile duct. There is a global increase in the incidence of ECC. Surgical resection is the most common treatment for ECC during the early stages. However, when presented as a metastatic or unresectable disease, ECC has a high risk of recurrence that restricts optimal survival.
The left and right bile ducts leave the liver and combine to form the common hepatic duct. Perihilar cancer occurs in the bile duct in the area where these two ducts leave the liver. The condition is also known as a Klatskin tumor, as Gerald Klatskin initially described it. It is usually diagnosed in the advanced stage and has a poor prognosis. Currently, the primary management option for perihilar bile duct carcinoma is a complete hepatectomy.
The ducts from the gallbladder and the liver combine to form a common bile duct. The common bile duct delivers the bile into the small intestine. Distal cholangiocarcinoma occurs in the area of connection between the gallbladder and liver ducts. Due to its anatomical location and inherent aggressiveness, patients have a poor prognosis. Surgical resection is the primary management option for this condition. The surgeon may also perform pancreaticoduodenectomy or hepatopancreaticoduodenectomy.
Hilar cholangiocarcinoma is a rare condition and is more common in people over 60 years of age. Patients with this condition usually have a poor prognosis. It comprises over 60% of cholangiocarcinoma cases.
Staging is an important aspect of bile duct carcinoma management. It helps doctors understand the extent of the disease and, accordingly, create a treatment plan. The following are the different stages of bile duct cancer (intrahepatic cholangiocarcinoma):
Stage 0 bile duct cancer is also known as carcinoma in situ. In this stage, the abnormal cells are in the innermost intrahepatic duct lining. These cells are not cancerous; however, they can potentially transform into malignant cells and spread to surrounding healthy tissues.
Stage 1 bile duct cancer is divided into stages 1A and 1B. The tumor in stage 1A bile duct carcinoma is limited to intrahepatic bile duct and is of size ≤5 cm. The tumor in stage 1B bile duct carcinoma is limited to the intrahepatic bile duct and has a size >5 cm.
Stage 2 bile duct cancer is characterized by the presence of a tumor spread into the intrahepatic bile duct wall or into a blood vessel, or by the presence of more than one tumor in the intrahepatic bile duct that may have spread into a blood vessel.
Stage 3 bile duct cancer is divided into stages 3A and 3B. In stage 3A bile duct carcinoma, the tumor has spread to the outer liver lining. In stage 3B bile cancer, the cancer has spread into the surrounding tissues and organs of the liver, such as the diaphragm, abdominal wall, common bile duct, colon, duodenum, stomach, and a part of the vena cava. The cancer in stage 3B would have also spread to the nearby lymph nodes. However, the cancer has not spread to distant organs.
Stage four bile duct cancer refers to the most advanced stage. This stage is characterized by the spread of the disease to distant organs, such as the lungs, bones, and distant lymph nodes.
Bile duct cancer is a rare condition characterized by malignant cells in the bile duct. There are several bile duct cancer types, depending on the location of the cancer. These include intrahepatic cholangiocarcinoma, extrahepatic cholangiocarcinoma, and hilar cholangiocarcinoma. Extrahepatic cholangiocarcinoma is further divided into perihilar bile duct carcinoma and distal cholangiocarcinoma. Lastly, bile duct carcinoma is staged between 0 and 4, depending on the extent of the disease’s spread, with 0 referring to the early stage and 4 referring to the advanced stage of the disease.