Risks for biliary tract cancer

Some things can affect your risk, or chance, of developing cancer. Certain behaviours, substances or conditions can increase or decrease the risk. Most cancers are the result of many risks. But sometimes cancer develops in people who don't have any risks.

Having gallstones is the main risk for biliary tract cancer, which includes gallbladder cancer and bile duct cancer.

The risk of developing biliary tract cancer increases with age. More women than men develop gallbladder cancer, while more men than women develop bile duct cancer.

Gallbladder cancer rates are higher in certain countries and ethnic groups. In North America, the number of people who get gallbladder cancer is low, but the rate of gallbladder cancer for people with Indigenous and Latin American ancestry is higher than average.

Some of the things that increase the risk for biliary tract cancer may also cause precancerous conditions. Precancerous conditions of the biliary tract include gallbladder polyps and biliary intraepithelial neoplasia. They are not cancer, but they can sometimes become biliary tract cancer if they are not treated.

The following can increase your risk for biliary tract cancer. Many of these risks can't be changed. But in some cases, there are things you can do to lower your risk.

Gallstones

Chronic inflammation of the biliary tract

Choledochal cysts

Anomalous junction of the pancreaticobiliary duct

Excess weight

Certain infections

Inflammatory bowel disease

Contact with Thorotrast

Contact with 1,2-dichloropropane

Gallstones are stone-like masses that form when the substances that make up bile harden. Having gallstones is called cholelithiasis. It's a common condition, but it develops more often in women.

Although having a history of gallstones is the most common risk for biliary tract cancer, only a very small number of people with gallstones will develop gallbladder cancer.

Conditions that cause inflammation of the biliary tract increase the risk of developing gallbladder or bile duct cancer.

Cholecystitis is inflammation of the gallbladder. It's most commonly caused by gallstones blocking the bile ducts. Over time, inflammation damages the gallbladder, causing scarring and thickening of the gallbladder walls.

Porcelain gallbladder is a rare condition. It happens when calcium builds up on the walls of the gallbladder, causing them to harden (calcify). It usually occurs when the gallbladder wall is heavily scarred due to chronic cholangitis (bile duct inflammation).

Primary sclerosing cholangitis is inflammation of the bile ducts. Over time, inflammation damages the bile duct walls, causing scarring and narrowing of the bile ducts.

Choledochal cysts are a rare congenital condition of the biliary tract that cause abnormally wide (dilated) bile ducts. They can cause inflammation and an abnormal flow of bile in the bile ducts and gallbladder.

There are 5 types of choledochal cysts. They are classified according to the location and amount of dilation. Type 5 (also called Caroli disease) is the most severe. When it's combined with a buildup of liver scarring (fibrosis), it's called Caroli syndrome.

The pancreaticobiliary duct junction is the point where the pancreatic duct and the common bile duct join. Anomalous junction of the pancreaticobiliary duct (AJPD) is a rare congenital abnormality that causes this junction to be outside the wall of the duodenum.

AJPD causes pancreatic digestive juices to flow back into the bile ducts instead of into the small intestine. This can cause inflammation of the biliary tract.

Overweight or obesity increases the risk for biliary tract cancer.

Learn more about how to have a healthy body weight.

Infections with the following parasites or bacteria increase the risk of developing biliary tract cancer.

Liver flukes are a group of parasites, including Opisthorchis viverrini (O. viverrini) and Clonorchis sinensis (C. sinensis). They can cause inflammation of the liver and biliary tract. Eating raw or undercooked freshwater fish or shrimp from areas where liver flukes are found can allow the infection to enter the body. Sometimes you can have the parasites in your body but not have any symptoms for many years. Infection with liver flukes increases the risk for bile duct cancer.

Salmonella typhi (S. typhi) is a type of bacteria that causes typhoid fever. Sometimes you can have the bacteria in your body but not have any symptoms. Typhoid fever can be spread from person to person through contact with stool (poop) or urine (pee). Infection with S. typhi, even if it doesn't cause symptoms, increases the risk for gallbladder cancer.

Inflammatory bowel disease (IBD) is another name for ulcerative colitis and Crohn's disease. IBD is a type of autoimmune disease that causes inflammation of the gastrointestinal tract. Studies show that people with IBD have a higher risk for cancer of the biliary tract. People with both IBD and primary sclerosing cholangitis have an even higher risk.

Thorium dioxide (Thorotrast) is a contrast medium that was used for imaging tests in the past. Studies show that people who were injected with Thorotrast have a higher risk for gallbladder cancer.

Coming into contact with 1,2-dichloropropane at work increases the risk for biliary tract cancer.

1,2-dichloropropane is a chemical used in the printing, rubber-making and wax-making industries, as well as in the production of other chemicals. Coming into contact with 1,2-dichloropropane increases the risk for bile duct cancer.

Find out more about how to be safe at work.

The following have been linked with biliary cancer, but more research is needed to know for sure that they are risks:

• family history of gallbladder or bile duct cancer
• type 2 diabetes
• hepatitis B virus (HBV) and hepatitis C virus (HCV) infection
• Helicobacter pylori (H. pylori) infection (a bacteria that infects the stomach)
• number of pregnancies a woman has had (parity)
• cirrhosis of the liver or biliary tract
• drinking alcohol
• smoking tobacco

To make the decisions that are right for you, ask your doctor questions about risks. Learn how cancer can be prevented and what you can do to reduce your risk.