Gallbladder cancer typically strikes older people (aged 70 and above). It is more common among Mexican Americans, southwestern Native Americans, and people from certain South American countries, particularly Chile.
Gallstones and Inflammation
Gallstones -- hard, rocklike formations made of cholesterol and other substances in the gallbladder --are the biggest risk factor for gallbladder cancer. Up to 90 percent of people diagnosed with gallbladder cancer also have gallstones and chronic inflammation of the gallbladder. These conditions are more common in women, who are twice as likely as men to develop gallbladder cancer. People with larger gallstones (3 centimeters) are ten times more likely to develop gallbladder cancer than those with small stones (1 centimeter). However, gallstones are very common, and most people with gallstones never develop gallbladder or bile duct cancer.
Other risk factors for gallbladder cancer include:
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Porcelain Gallbladder
This is a condition in which the gallbladder becomes covered in calcium deposits, resembling porcelain ceramic. Porcelain gallbladder can occur when the gallbladder becomes inflamed.
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Typhoid
People who are chronically, or persistently, infected with salmonella (the bacterium that causes typhoid) are six times more likely to develop gallbladder cancer than those who are not infected.
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Obesity
Many patients with gallbladder cancer are overweight or obese, and have a high-carbohydrate or low-fiber diet.
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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 usually symptomless. Some polyps are precancerous and can progress to cancer. Polyps that are 1 centimeter or larger, appear to be growing, or have a broad base should be removed to prevent cancer.
Risk Factors for Bile Duct Cancer
Like gallstones, smaller stones that form in the bile ducts can lead to chronic inflammation and increase the risk of developing bile duct cancer. Other inflammatory conditions can increase the risk of developing bile duct cancer:
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Ulcerative Colitis
Ulcerative colitis is an inflammation of the large intestine that is often associated with inflammation of the bile duct (a condition known as sclerosing cholangitis). Ulcerative colitis can progress to cancer, particularly in people exposed to other carcinogens such as cigarette smoke.
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Biliary Parasites
Although rarely seen in the United States, food- or water-borne parasites that reside in the bile ducts are common in Asia and raise the risk of developing bile duct cancer.
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Congenital Bile Duct Cysts (Choledochal Cysts)
These bile-filled sacs are connected to the common bile duct. Congenital bile duct cysts are typically diagnosed in childhood. The lining of these sacs often contains precancerous cells that increase the risk of developing cancer later in life.
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Chronic Hepatitis C
This inflammatory disease -- the most common risk factor for liver cancer --also is considered a risk factor for cancer of the intrahepatic bile ducts. (For more information about hepatitis, visit the Risk Factors section of the Primary Liver Cancer overview.)
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Smoking
A recent study suggests that intrahepatic bile duct cancer is more common among heavy smokers.
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Diabetes
This condition appears to be an increasingly important risk factor for intrahepatic bile duct cancer.
