Bile duct cancer can be a challenging condition to diagnose. You usually need to have a number of different tests before an accurate diagnosis can be made. Some possible tests that you may have are described below.
Blood tests
If you have bile duct cancer, the cancerous cells may release certain proteins 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, so a positive blood test does not necessarily mean that you have bile duct cancer.
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 – which 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 will be 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 will be able to detect blockages in your bile duct that could be the result of bile duct cancer.
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) will be numbed using local anaesthetic, and the doctor will pass a needle through your skin and into your liver. A special dye that shows up clearly will be injected 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
A biopsy is a procedure in which 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 and into your lymphatic system.
Staging
After all of the tests listed above have been completed, it should be possible to establish the stage that 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 TMN 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 TMN system is widely used, but it can sometimes be difficult for someone with little or no medical expertise to understand. Therefore, for clarity, the rest of this article will use 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 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
