Diagnosing bile duct cancer

Bile duct cancer can be a challenging condition to diagnose. You usually need several different tests before an accurate diagnosis can be made.

You may visit your GP first, who will examine you and ask about your symptoms and medical history. If cancer is suspected, you will be referred to a specialist for tests.

Some of these are described below.

Blood tests

If you have bile duct cancer, the cancerous cells may release certain chemicals that can be detected using blood tests. These types of proteins are known as tumour markers.

However, tumour markers can also be caused by other conditions. A positive blood test does not necessarily mean you have bile duct cancer, and a negative blood test does not always mean you don’t.

Scans

A number of scans can be used to examine your bile ducts in more detail and check for lumps or other abnormalities that could be the result of cancer. These scans include:

• ultrasound scan – high frequency sound waves are used to build up a picture of the inside of your body
• computer tomography (CT) scan – a series of X-rays of your liver are taken and a computer is used to assemble them into a more detailed three-dimensional image
• magnetic resonance imaging (MRI) scan – this uses a strong magnetic field and radio waves to produce a picture of the inside of your liver

Endoscopic retrograde cholangiopancreatography (ERCP)

During endoscopic retrograde cholangiopancreatography (ERCP), you will be injected with a special liquid that makes your bile ducts show up more clearly on an X-ray scanner.

The X-ray scanner is used to guide an endoscope (a small, flexible tube with a camera at the end) down your throat and into your bile duct. The endoscope can detect blockages in your bile duct that could be the result of bile duct cancer.

Spyglass

An advanced form of ERCP is a special test called a spyglass. This involves passing a specialised endoscope into the bile duct so any abnormalities can be spotted. It also enables a biopsy to be taken at this stage.

While this test can help confirm a diagnosis in uncertain cases, it is very expensive and requires specialist training. Therefore, it is only available at a limited number of centres.

Percutaneous transhepatic cholangiography (PTC)

Percutaneous transhepatic cholangiography is a procedure carried out to obtain a detailed X-ray image of your bile duct.

The side of your abdomen (tummy) is numbed using local anaesthetic, and a special dye that shows up on X-rays is injected through your skin and into your liver duct.

As with ECRP, PTC is a useful way of detecting any blockages in your bile duct that could be caused by bile duct cancer.

Biopsy

If scans and tests indicate you may have bile duct cancer, a biopsy is carried out to confirm a diagnosis.

During a biopsy a small sample of tissue is taken from the body and checked under a microscope for the presence of cancerous cells.

A biopsy is usually performed while ERCP or PTC is being carried out. As well as taking bile and tissue samples from your bile duct, samples may be taken from nearby lymph nodes. This is to check whether the cancer has spread from your bile duct into your lymphatic system.

Staging

If tests confirm you have cancer, it should be possible to establish the stage your cancer is at. The stage describes how far the cancer has spread.

There are two ways of categorising the staging of bile duct cancer. The first is known as the TNM staging system, where:

• T indicates the size of the tumour
• N indicates whether the cancer has spread to nearby lymph nodes
• M indicates whether the cancer has spread to other parts of the body (metastasis)

The TNM system is widely used, but can sometimes be difficult for non-medical professionals to understand. Therefore, this article uses the second staging system, where the stages of bile duct cancer are described numerically.

The stages are:

• stage 1A – the cancer is contained inside the bile duct
• stage 1B – the cancer is beginning to spread beyond the walls of the bile duct but has not spread into the surrounding tissue or lymph nodes
• stage 2A – the cancer has spread into nearby tissue, such as the liver or pancreas, but has not spread into the lymph nodes
• stage 2B – the cancer has spread into nearby tissue and lymph nodes
• stage 3 – the cancer has spread into the major blood vessels that supply the lungs, or into organs such as the stomach, gallbladder or bowel
• stage 4 – the cancer has spread into distant organs, such as the lungs