Bile duct cancer

Cancers of the bile duct are rare in the Western world. There are approximately 600 new cholangiocarcinomas diagnosed each year in the UK.

The bile ducts are the tubes connecting the liver and gall bladder to the small intestine (small bowel). Bile is a fluid made by the liver and stored in the gall bladder. Its main function is to break down fats during their digestion in the small bowel. In people who have had their gall bladder removed, bile flows directly into the small intestine. The bile ducts and gall bladder are known as the biliary system.

Diagram showing the position of the bile duct

Cancer is classified according to the type of cell from which it starts. Cancer of the biliary system almost always starts in a type of tissue called glandular tissue and is then known as adenocarcinoma.

If the cancer starts in the part of the bile ducts contained within the liver it is known as intra-hepatic. If it starts in the area of the bile ducts outside the liver it is known as extra-hepatic. This information concentrates mainly on extra-hepatic bile duct cancers. Intra-hepatic bile duct cancers may be treated like primary liver cancer.

Causes of bile duct cancer

The cause of most bile duct cancers is unknown but they are more likely to occur in people who are born with (congenital) abnormalities of the bile ducts such as choledochal cysts. People who have a chronic inflammatory bowel condition, known as ulcerative colitis, are also at an increased risk of developing this type of cancer.

In Africa and Asia, infection with a parasite known as the liver fluke is thought to cause a large number of bile duct cancers. Bile duct cancer, like other cancers, is not infectious and cannot be passed on to other people.

Signs and symptoms

If cancer develops in the bile ducts it may block the flow of bile from the liver to the intestine. This causes the bile to flow back into the blood and body tissues, and leads to the skin and whites of the eyes becoming yellow (known as jaundice). The urine also becomes a dark yellow colour and stools (bowel motions) are pale. The skin may become itchy. Mild discomfort in the abdomen, loss of appetite, high temperatures (fevers) and weight loss may also occur.

These symptoms can be caused by many things other than bile duct cancer, but any jaundice or any symptoms which get worse or last for a few weeks should always be checked by your doctor.

How it is diagnosed

Usually you begin by seeing your GP, who will examine you. They will refer you to a hospital specialist for any tests that may be necessary and for expert advice and treatment. The doctor at the hospital will take your full medical history, do a physical examination and take blood samples to check your general health and your liver is working properly.

The following tests are commonly used to diagnose bile duct cancer:

Ultrasound scan Sound waves are used to make up a picture of the bile ducts and surrounding organs. These scans are done in the hospital's scanning department. You will be asked not to eat, and to drink clear fluids only (nothing fizzy or milky) for 4–6 hours before the scan. Once you are lying comfortably on your back, a gel is spread onto your abdomen. A small device, like a microphone, is then rubbed over the area. The sound waves are converted into a picture using a computer. The test is completely painless and takes 15–20 minutes.

CT (computerised tomography) scan A CT scan takes a series of x-rays which are fed into a computer to build up a detailed picture of your bile ducts and surrounding organs. On the day of the scan you will be asked not to eat or drink anything for at least four hours before your appointment. You will be given a special liquid to drink an hour before the test and again immediately before the scan. The liquid shows up on x-ray to ensure that a clear picture is obtained.

Once you are comfortably positioned on your back on the couch, the scan can be taken. About half-way through the scan a special dye will be injected into a vein to show up the blood vessels. This may make you feel warm or ‘flushed’ for up to half an hour. The test itself is completely painless, but it will mean that you have to lie still for about 10–30 minutes. If you had little to drink before the scan, you may be advised to drink plenty afterwards to make up for this.

MRI (magnetic resonance imaging) scan This test is similar to a CT scan, but uses magnetism instead of x-rays to build up cross-sectional pictures of your body. During the test you will be asked to lie very still on a couch inside a large metal cylinder which is open at both ends. The whole test may take up to an hour. It can be slightly uncomfortable and some people feel a bit claustrophobic during the scan, which is also very noisy. You will be given earplugs or headphones to wear. A two-way intercom enables you to talk with the people controlling the scanner.

ERCP (endoscopic retrograde cholangio-pancreatography) This is a procedure by which an x-ray picture of the pancreatic duct and of the bile duct can be taken. It may also be used to unblock the bile duct if necessary.

You will be asked not to eat or drink anything for about six hours before the test so that the stomach and duodenum (first part of the small bowel) are empty. You will be given an injection to make you relax (a sedative) and a local anaesthetic spray will be used to numb your throat. The doctor will then pass a thin flexible tube known as an endoscope through your mouth into your stomach and into the duodenum just beyond it. Looking down the endoscope, the doctor can find the opening through which the bile duct and the duct of the pancreas drain into the duodenum. A dye which can be seen on x-ray can be injected into these ducts and the doctor will be able to see whether there is any abnormality or any blockage in the ducts.

If there is a blockage it may be possible for the doctor to insert a small tube known as a stent. You may have some discomfort during this procedure; if you do, it is important that you let your doctor know. You will be given antibiotics beforehand (to help prevent any infection) and will probably stay in hospital for one night afterwards.

PTC (percutaneous transhepatic cholangiography) This is another procedure by which your doctor can obtain an x-ray picture of the bile duct. You will be asked not to eat or drink anything for about six hours before the test and will be given a sedative as for the ERCP.

An area on the right side of your abdomen will be numbed with a local anaesthetic (an injection) and a thin needle will be passed into the liver through the skin. A dye will be injected through the needle into the bile duct within the liver. X-rays will then be taken to see if there is any abnormality or blockage of the duct.

You may feel some discomfort as the needle enters the liver. You will be given antibiotics before and after this procedure (to help prevent infection) and you will stay in hospital for at least one night afterwards.

Angiography As the bile duct is very close to the major blood vessels of the liver, a test called an angiogram may be done. The angiogram can check whether the blood vessels are affected by the tumour.

A fine tube is inserted into an artery in your groin and a dye is injected through the tube. The dye circulates in the arteries to make them show up on x-ray. An angiogram is carried out in a room within the x-ray department. Sometimes an MRI scan can be used to show up the blood vessels of the liver and then an angiogram will not be necessary.

Biopsy The results of the previous tests may make your doctor strongly suspect a diagnosis of cancer of the bile duct, but the only way to be sure of the diagnosis is to take some cells or a small piece of tissue from the affected area of the bile duct to look at under a microscope. This is called a biopsy and may be carried out during an ERCP or PTC.

A fine needle is passed into the tumour through the skin after the area has been numbed using a local anaesthetic injection. CT or ultrasound may be used at the same time, to make sure that the biopsy is taken from the right place.

Endoscopic ultrasound scan (EUS) This scan is similar to an ERCP but involves an ultrasound probe being passed down the endoscope to take an ultrasound scan of the pancreas and surrounding structures.

Staging

The stage of a cancer is a term used to describe its size and whether it has spread beyond its original site. Knowing the particular type and the stage of the cancer helps the doctors to decide on the most appropriate treatment.

Cancer can spread in the body, either in the blood stream or through the lymphatic system. The lymphatic system is part of the body’s defence against infection and disease. The system is made up of a network of lymph glands (also known as lymph nodes) that are linked by fine ducts containing lymph fluid. Your doctors will usually look at the lymph nodes close to the biliary system in order to find the stage of your cancer.

• Stage 1A The cancer is contained within the bile duct.
• Stage 1B The cancer has spread through the wall of the bile duct but has not spread into nearby lymph nodes or other structures.
• Stage 2A The cancer has spread into the liver, pancreas or gall bladder or to the nearby blood vessels, but not the lymph nodes.
• Stage 2B The cancer has spread into nearby lymph nodes.
• Stage 3 The cancer is affecting the main blood vessels that take blood to and from the liver, or it has spread into the small or large bowel, the stomach or the abdominal wall. Lymph nodes in the abdomen may also be affected.
• Stage 4 The cancer has spread to distant parts of the body such as the lungs.

If the cancer comes back after initial treatment, this is known as recurrent cancer.

Grading

Grading refers to the appearance of the cancer cells under the microscope and gives an idea of how quickly the cancer may develop. Low-grade means that the cancer cells look very like normal cells; they are usually slow-growing and are less likely to spread. In high-grade tumours the cells look very abnormal, are likely to grow more quickly and are more likely to spread.