Bile Duct Cancer (Cholangiocarcinoma)

Introduction

The bile duct is a network of thin tubes, which collects bile from the liver and drains it into the intestine. The bile duct is a tree-like structure with multiple branches in the liver, which then combines to form right and left hepatic duct draining right and left lobe of the liver. These two then join, the joint called hilum or confluence, becomes the common bile duct (gallbladder also connects to it through cystic duct). Common bile duct then continues downstream, is joined by pancreatic duct and opens into the intestine (in the part of the intestine called the duodenum).

Bile duct cancer is also called cholangiocarcinoma. In this cancerous cells form in the bile duct and then grows and spreads. Bile duct cancer (cholangiocarcinoma) is of three types, depending on the part of the bile duct it arises from.

Types

Intrahepatic bile duct cancer (cholangiocarcinoma): The bile ducts located within the liver are intrahepatic. In intrahepatic cholangiocarcinoma, cancer originates in these ducts.

Perihilar bile duct cancer (cholangiocarcinoma): This term describes cancer arising from the bile duct at the hilum or confluence (remember, this is where right and left hepatic duct joins to form a single tube). It is also called hilar cholangiocarcinoma or Klatskin tumor.

Distal bile duct cancer (cholangiocarcinoma): This occurs in the part of the bile duct which is close to its entry into the intestine, where it passes through the head of the pancreas.

Symptoms

• Jaundice (yellowing of the eyes, urine and skin)
• Abdominal pain
• Fever
• Itching
• Weight loss and loss of appetite

Risks

Risk factors for bile duct cancer include:

• Primary sclerosing cholangitis (a disease which causes inflammation of the bile ducts)
• Ulcerative colitis and Crohn disease (Inflammation of the large intestine)
• Cysts of the bile duct (choledochal cyst)
• Infection with a parasite called the liver fluke
• Cirrhosis and Viral hepatitis (hepatitis B and C)
• Hepatolithiasis (stones in the liver) and choledocholithiasis (stones in the bile duct)
• Toxins e.g. thorotrast
• Smoking and alcohol abuse
• Diabetes and obesity

Diagnosis Tests

• Blood tests: These include routine blood tests and liver function test.
• Tumor markers: In bile duct cancer CA 19-9 and carcinoembryonic antigen (CEA) may be increased.
• Ultrasound: This is a basic test to see the liver and bile ducts.
• Computed tomographic scan (CT): Thin cut triple-phase CT is done to visualize cancer and the involved parts of the organs.
• Magnetic resonance imaging (MRI) and magnetic resonance cholangiopancreatography (MRCP): MRI uses strong magnetic fields, radio waves and computer to generate images of inside organs. This imaging modality gives a detailed view of the bile duct and cancer.
• Positron emission tomography (PET): It is a functional imaging technique which is sometimes used for staging.
• Biopsy or cytology: In this procedure, a small sample of tumor or few cells from this is obtained and examined under the microscope confirming the diagnosis. This is usually not required in bile duct cancers which can be removed surgically.

Stages

Stages

Treatments

If detected at a stage where they can be removed by surgery, offers the best chance of cure. The surgical option depends on the type of cholangiocarcinoma.

Surgery for intrahepatic cholangiocarcinoma:

It requires removal of the bile duct and the part of the liver it is affecting. The surgical procedure to remove a part of the liver is called hepatectomy or liver resection. The joint of the left and right duct also needs excision in many cases. The bile is then made to reach intestine by joining a loop of intestine to the cut end of the bile duct of remnant liver.

Surgical excision is done only for those patients whose tumors have not spread to distant organs. Besides complete resection should be feasible with enough healthy liver left behind. Sometimes the amount of liver which needs to be removed is too big and hence the remaining liver is small and not compatible with survival. In such cases, portal vein embolization can be done a few weeks before the surgery to increase the size of the liver, which is going to remain after surgery.

Surgery for hilar cholangiocarcinoma:

The surgery for hilar cholangiocarcinoma resects involved intrahepatic and extrahepatic bile ducts including the confluence of the right and left hepatic duct along with draining portal lymph nodes. Successful resection of the biliary confluence almost always involves resection of the right liver, left liver or larger part of the liver (depending on the extent of tumor). The bile is then made to reach intestine by joining a loop of the small intestine to the cut end of the bile duct of the remnant liver called hepaticojejunostomy.

Sometimes the amount of liver which needs to be removed is too large and hence the remaining liver is inadequate and not compatible with survival. In such cases, portal vein embolization can be done a few weeks before the surgery to increase the volume of the liver, which is going to remain after surgery.

Surgery for distal cholangiocarcinoma:

The operation to surgically remove distal cholangiocarcinoma is called Whipple operation , also known as pancreaticoduodenectomy . In this, head of the pancreas is removed along with duodenum, bile duct, gall bladder, part of the stomach, a small part of the small intestine and adjacent lymph nodes. To restore gastrointestinal continuity, the small intestine is then joined to the pancreas (sometimes pancreas is joined to the stomach), remaining bile duct and stomach.

Many times the level of jaundice is too high for upfront surgery and in such cases, jaundice needs to be decreased before surgery by draining the bile. The procedure to drain bile is called Endoscopic retrograde cholangiopancreatography (ERCP) or Percutaneous transhepatic biliary drainage (PTBD). These drainage procedures are also needed in surgically unresectable cases as a means of palliation.

Tumors which cannot be removed surgically are treated by chemotherapy and/or radiotherapy. Chemotherapy is the use of special drugs to kill cancer cells and radiotherapy is the use of high-powered X-ray beams to kill cancer cells.