Bile Duct Cancer
What Are The Functions and Location of the Bile Ducts?
The bile duct has a critical function of moving the bile from the liver (where it is produced) and from the gallbladder (where it is stored), eventually emptying the bile into the duodenum (first part of your small intestine). Bile helps in the digestion of fats from the food that you eat.
The bile ducts start from the liver as tiny tubes called ductules. These ductules join together to form small ducts and, in turn, they merge into larger ducts and form the right and left hepatic ducts. These two ducts exit from the liver and join together as the common hepatic duct. Lower down, it unites with the cystic duct that comes from the gallbladder and is called the common bile duct. Then, the common bile duct traverses a part of the pancreas and joins the pancreatic duct. It empties into the duodenum, the first part of the intestines.
What Are The Types of Bile Duct Cancer?
Cancer, just like anywhere in the body, can develop in any part of the bile ducts. They are classified into 2 types:
- Intrahepatic bile duct cancer: This evolves from the smaller bile ducts that are found inside the liver.
- Extrahepatic bile duct cancers: These are located in the bile ducts (outside the liver), and are divided into two types:
- Perihilar bile duct cancers or Klatskin tumors: They are the most common among all kinds of bile duct cancers and makes up more than half of the bile duct cancers. Klatskin tumors develop at the area where the left and right hepatic ducts join.
- Distal bile duct cancers: These make up 2 to 3 out of every 10 bile duct cancers. They are located lower down the bile duct and closer to the small intestine.
Bile duct cancers are also categorized by the cell types.
- Cholangiocarcinomas are the most common. They originate from the glandular cells lining the duct.
- Sarcomas, lymphomas, and small cell cancer are very rare.
Prevalence of Bile Duct Cancers
Worldwide, bile duct cancers are rare. However, they are common in South East Asia because of a parasitic infestation by a liver fluke.
What are The Risk Factors for Developing Bile Duct Cancers?
Generally, conditions causing inflammation of the liver and the bile ducts increase your risk of developing bile duct cancer.
These conditions include:
- Primary sclerosing cholangitis or inflamed bile ducts or cholangitis that leads to scar tissue formation.
- Bile duct stones
- Cirrhosis, a condition which damages the liver and causes scar tissue. This is often due to alcoholism and viral diseases like hepatitis B and C.
Other risk factors include:
- Liver fluke infections by Clonorchis sinensis and Opisthorchis viverrini, which mostly occur in Asian countries, where raw or poorly cooked infected fish are eaten. The liver flukes can invade the bile ducts.
- Bile duct and pancreatic duct anatomical abnormalities, where the digestive juices from the pancreas flow backward into the bile ducts and prevent bile from being emptied normally.
- A rare congenital condition called Caroli’s syndrome, which is a dilatation of the intrahepatic bile ducts.
- Inflammatory bowel diseases, such as ulcerative colitis and Crohn’s disease
- Older age
- Ethnicity and geography – more common in South East Asia
What Are The Common Sign and Symptoms of Bile duct Cancer?
Like most cancers, signs and symptoms of Cholangiocarcinoma or bile duct cancer occur later in the course of the disease. However, if symptoms occur earlier, it may result in early diagnosis, better treatment, and better outcomes.
Most signs and symptoms occur due to the blockage of the bile duct. These symptoms include:
- Itching due to excessive bilirubin in the skin
- Greasy stools or light colored stools – This is a result of the bile not being able to reach the small intestines due to blockage. Bilirubin is a pigment in the bile that is responsible for the brownish color of the stools. Thus, the stools become light colored. Also, because of the absence of bile to digest fat in the food, the undigested fat causes stools to be bulky and greasy which floats in the toilet.
- Dark urine
- Abdominal pain at the right side below the ribs
- Loss of appetite
- Weight loss
- Nausea and vomiting
How To Diagnose Bile Duct Cancers?
The following methods are used for diagnosing the bile duct cancer:
- History and physical examination done by your doctor.
- Blood tests, such as liver function tests, which determine bilirubin levels. A high level of bilirubin may mean there may be problems with the liver, gallbladder or the bile duct. High levels can indicate a blockage in the bile duct.
- Tumor markers – In bile duct cancers, the tumor markers (CEA and CA 19-9) can be abnormally high and can mean a bile duct cancer.
- Abdominal ultrasound
- Computerized tomography or CT scan – presents a detailed cross-section of your body wherein a scanner takes pictures of the patient’s body to determine if tumors or masses are present in the bile duct. This procedure can stage the cancer and visualize blood vessels around the bile ducts. It can also guide a biopsy needle into the suspected tumor or metastasis called a CT-guided needle biopsy, where samples are taken for study.
- Magnetic resonance scan: including Magnetic Resonance Cholangiopancreatography (MRCP), which is a non-invasive type of imaging that visualizes the bile ducts.
- Endoscopic ultrasound – This entails the use of an ultrasound probe with a viewing device at its end. This probe is passed through the mouth and into the small intestine near the bile ducts for formal evaluation of the tumour. Fine needle biopsy can be performed at the same sitting to aid in the diagnosis of tumours.
- Endoscopic retrograde cholangiopancreatography (ERCP) – It is a procedure where your doctor passes a long, flexible tube down your throat all the way down to your duodenum. Then, a small catheter is passed from the end of the endoscope and into the common bile duct. A contrast dye is introduced to outline the bile ducts and pancreatic ducts and X-rays are taken. This identifies the blockage of the ducts. Your doctor can take samples of cells or fluid with this technique. Additionally, a stent can be introduced to keep the duct open.
Other tests may be done to take a direct look at the bile duct including:
- Laparoscopy:In this procedure, small cuts are made on the abdomen, and a thin lighted tube equipped with a video camera (called a laparoscope) is inserted to look at the gallbladder, bile duct and liver and the surrounding tissues and organs. This is usually performed in an operating room under general anesthesia. This is useful in assessing the stage of the cancer and helps in the treatment plan.
- Cholangioscopy: This can be performed during ERCP. A thinner fiber optic tube with a tiny camera is passed down through the larger tube used for ERCP and inserted in the bile ducts. This method is used to examine blockages, stones or tumor.
By using the aforementioned techniques, your doctor makes a diagnosis and stages bile duct cancer. From the staging, the treatment options can be planned. Usually, treatment consists of surgery if the cancer is operable but surgery can also be palliative. Additionally, radiation and chemotherapy may be utilized as part of the treatment.
If you’re experiencing, unusual symptoms that you suspect are attributable to the bile duct or have recently been diagnosed with bile duct problems, seek an early consultation with a hepatobiliary surgeon who can advise you!