Bile duct cancer is rare, but experts think it’s becoming more common. A recent estimate is that there are around 4 cases diagnosed for every 100,000 people. Around 2,200 people are diagnosed in England each year. But it’s still a rare cancer. For comparison, around 56,000 people are diagnosed annually with breast cancer.
There are some factors that we know can increase your risk, but most people diagnosed with bile duct cancer don’t have any of them. In fact, we don’t know what causes it in around 7 out of 10 cases (70%). Doctors call this ‘sporadic’ cancer.
It’s a bit of a myth that liver cancer is always related to drinking alcohol. As you’ll see below, there are several other factors that are much more strongly linked to bile duct cancer. In fact, the evidence of a link to alcohol is still unclear.
Who gets bile duct cancer?
Most people who get bile duct cancer are older. It’s most common in people between 50 and 70 years old. People who have another medical condition linked to bile duct cancer (see below) tend to be diagnosed at a younger age.
Most types of cancer are more common in older people, because there has been more time for their body cells to collect damage. DNA mistakes (mutations) can happen by chance when cells are dividing, or because the body has been exposed to something that damages cells, such as cigarette smoke.
Overall, bile duct cancer is slightly more common in men than in women. However, intrahepatic bile duct cancer is twice as common in women.
Risk factors for bile duct cancer
There are some risk factors that cause long term inflammation or irritation of the bile ducts. In time, this can lead to cancer.
There is a slightly increased risk of bile duct cancer if you’ve had gallstones.
Stones can develop in the ducts as well as the gallbladder. In the ducts, they increase risk of bile duct cancer if you’ve had them for a long time. They can block the flow of bile and cause inflammation.
In Western countries, stones in the bile ducts are much less common than stones in the gallbladder.
Read about gallstones on the British Liver Trust main website.
Primary sclerosing cholangitis (PSC)
This is a long term (chronic) inflammatory disease. Around 1 in 3 people (33%) diagnosed with bile duct cancer also have PSC.
This doesn’t mean that everyone with PSC gets bile duct cancer. Estimates of risk vary from around 1 in 15 (7%) people to 1 in 6 (15%) people with PSC going on to develop bile duct cancer.
Read more about PSC on the British Liver Trust main website.
Bile duct cysts
These rare, slow growing cysts are usually present at birth. You may hear your doctor call this a choledochal cyst (say: kol-ee-doke-al sist).
Cysts are fluid filled sacs. They are not cancerous but about 1 in 6 (15%) become cancerous in adulthood.
Exposure to some toxins
There are some toxic chemicals that we know increase risk of bile duct cancer. This includes Thorotrast, an X-ray contrast agent, which can cause cancer decades later. It was banned in the UK in the 1960s, so is unlikely to be a cause these days.
Sometimes, exposure to toxins at work can increase cancer risk. There is some evidence that toxins in the car manufacturing, rubber and chemical industries may increase risk of bile duct cancer, but this is far from certain.
Liver fluke infection
Liver flukes are a parasite. It is very rare for people to pick them up in the UK. But they are a common cause of bile duct cancer in South East Asia.
The parasites live in lakes and rivers that are close to farm animals. You can get liver flukes by eating raw freshwater fish or uncooked wild freshwater plants such as watercress. Watercress from shops in the UK is grown in careful conditions so it should be safe. But always wash it well before eating.
Liver flukes collect in the bile ducts, where they can live for many years, causing infection and more rarely, cancer.
Other possible causes of bile duct cancer
There are some other potential risk factors for bile duct cancer where the evidence is much less clear. So they may increase your risk, but we don’t know for certain.
- Some liver diseases may increase risk, including cirrhosis and living with hepatitis B or C.
- Being overweight has been linked to an increased risk of intrahepatic bile duct cancer.
- An analysis of several studies together has shown that having diabetes increases bile duct cancer risk, but doctors are not sure exactly why this is.
- Smoking and drinking alcohol may increase risk but studies are unclear overall. Alcohol does increase risk in people with PSC (see above).
Unlike some other cancers, no specific genes that increase risk have been identified. So it is unlikely to be inherited. There is some evidence that people who have a close relative who’s had bile duct cancer have a slightly increased risk. But do remember that this is a rare disease, an increased risk can still be a small risk overall.
Most people who get bile duct cancer don’t have any known risk factors.
Content last reviewed: October 2022
Next review date: October 2025