Several risk factors have been identified that make a person more likely to develop gallbladder or bile duct cancer.
Gallstones and Inflammation of the Gallbladder
Gallstones -- hard, rock-like formations made up of cholesterol and other substances of the gallbladder -- are the most common risk factor for gallbladder cancer. According to the American Cancer Society, between 75 and 90 percent of people with gallbladder cancer have gallstones and chronically inflamed gallbladders when diagnosed. Both gallstones and inflammation of the gallbladder are more common among women than in men.
The size of the gallstones also increases the odds of developing gallbladder cancer: people with one or more large gallstones (3 centimeters or 1.2 inches) are 10 times more likely to develop gallbladder cancer than those with small gallstones (1 centimeter or 0.4 inches).
Stones in the bile ducts, which are similar to gallstones but smaller in size, also cause inflammation that can increase the risk of developing bile duct cancer.
However, having gallstones in the gallbladder or bile duct does not mean that a person will develop cancer in his or her lifetime. Gallstones -- in either the gallbladder or bile ducts -- are a very common condition, and the majority of people with gallstones will never develop gallbladder cancer.
Ethnicity and Geography
Mexican Americans and Native Americans in the southwestern United States tend to have a high rate of gallbladder cancer. People living in South American countries, in particular Chile, are also at higher risk.
Gender
Gallbladder cancer occurs twice as often among women as in men in the United States. The incidence of bile duct cancer is higher in men than in women.
Age
Like most cancers, age is a risk factor for both bile duct and gallbladder cancer.
Other Risk Factors
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Porcelain Gallbladder
This is a condition in which the gallbladder becomes covered in calcium deposits resembling porcelain ceramic. This sometimes occurs when the gallbladder becomes inflamed.
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Obesity
Patients with gallbladder cancer are often overweight or obese. A high-carbohydrate or low-fiber diet may increase a person's likelihood of developing gallbladder cancer.
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Typhoid
People who are chronically, or persistently, infected with salmonella are six times more likely to develop gallbladder cancer than those who are not infected.
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Family History
Gallbladder cancer sometimes runs in families.
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Gallbladder Polyps
Gallbladder polyps are growths that protrude from the gallbladder's mucous membrane. These polyps are rarely malignant, carry no symptoms, and require no to minimal treatment.
Disease of the Bile Ducts
Similar to gallbladder cancer, chronic or persistent inflammation of the bile ducts increases a person's chances of developing bile duct cancer. A number of inflammatory diseases increase the chances of bile duct cancer, including:
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Ulcerative Colitis
A condition that inflames the large intestine. Ulcerative colitis can lead to sclerosing cholangitis.
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Primary Sclerosing Cholangitis
An inflammation specific to the bile duct that leads to scar tissue formation. Smoking can increase the chances of sclerosing cholangitis developing into cancer.
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Biliary Parasites
Although rarely seen in the United States, these food- or water-borne parasites are very common in Asia.
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Congenital Bile Duct Cysts (Choledochal Cysts)
These bile-filled sacs are connected to the common bile duct and can grow over time to hold one to two quarts of bile. Congenital bile duct cysts are typically diagnosed in childhood. The lining of these sacs often contain precancerous cells that can increase the risk of developing cancer later in life.
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Hepatitis C
Viral hepatitis, which means inflammation of the liver, is the most common risk factor for liver cancer but because of the close proximity of the organs, it is also recognized as a risk factor for intrahepatic bile duct cancer (those that develop in those small duct channels inside the liver). See the Prevention section of the Primary Liver Cancer overview for more information on hepatitis.
