Risks and causes of gallbladder cancer

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Risks and causes of gallbladder cancer
Last updated 26 September 2008
Cancer Research UK

How common is gallbladder cancer?
What is a risk factor?
Age
Gallstones and gallbladder inflammation
Family history
Porcelain gallbladder
Cigarette smoking and other chemicals
Abnormalities of the pancreas and bile duct
Gallbladder polyps
Obesity
Diet
Race
Typhoid
Hormone replacement therapy (HRT)
How common is gallbladder cancer?
We don't know the exact causes of gallbladder cancer. We know that it is a rare cancer in the UK, with just under 570 cases diagnosed each year. This means that only about 1 in every 500 cancers diagnosed is a gallbladder cancer. It is more common in women than in men. About 7 out of every 10 cases diagnosed are in women.

What is a risk factor?
Anything that increases your risk of getting a disease is a risk factor. Different cancers have different risk factors. Even if you have one or more risk factors, it does not mean that you will definitely get the disease. We know of several risk factors for gallbladder cancer. We’ve also included information on factors that have been thought by researchers to be risk factors, but may not be, such as hormone replacement therapy - HRT.

Age
As with most cancers, gallbladder cancer is more common in older people than it is in younger people. There are very few cases in people under 70 years of age.

Gallstones and gallbladder inflammation
Gallstones and inflammation of the gallbladder (cholecystitis) are the most common risk factors for gallbladder cancer. Gallstones are hard lumps, like little rocks, that form in the gallbladder. They are mostly cholesterol, mixed with other substances found in bile. About 8 out of 10 people with gallbladder cancer (80%) have gallstones or an inflamed gallbladder at diagnosis. If you have one large gallstone, this is more of a risk factor than having several small ones.

Remember - gallstones are very common but gallbladder cancer is very rare. Most people with an inflamed gallbladder or gallstones do not get gallbladder cancer.

Family history
Studies show that people with a first-degree relative with gallbladder cancer are five times more likely to develop gallbladder cancer than people who do not have a relative with it. As gallbladder cancer is so rare, even if the risk is increased five times, the risk is still very small.

Porcelain gallbladder
Porcelain gallbladder means that calcium deposits build up on the inside wall of your gallbladder. This condition is a risk factor, but gallbladder cancer is still very rare in people who have it. If you've had lots of times with an inflamed gallbladder you may get porcelain gallbladder. If you have this condition, your doctor may suggest that you have surgery to take your gallbladder out.

Cigarette smoking and other chemicals
Cigarettes and some industrial chemicals contain nitrosamines. These are chemicals that can damage DNA and increase the risk of developing cancer. There is more about DNA damage and cancer in the how cells and tissues grow section.

People who smoke or work in the metal or rubber industry are more likely to develop gallbladder cancer. There is more about how smoking can affect your cancer risk on the Cancer Research UK website.

Abnormalities of the pancreas and bile duct
Some abnormalities of the pancreas and bile duct increase your risk of getting gallbladder cancer. These include:

Sacks of bile along the bile duct (choledochal cysts)
An abnormality of the join between the bile duct and the pancreas
‘Choledochal cyst’ is pronounced ‘kol-eh-doke-al sist’.

These are both conditions you are born with. They are very rare. Most people born with these conditions will develop symptoms in early childhood. But some do not develop any until adulthood. Most people with choledochal cysts have an abnormal bile duct junction as well.

Choledochal cysts are there from birth in affected people. They are sacs that connect to the bile duct and fill up with bile. They grow slowly and can end up holding up to 2 litres of bile. The cells that line the sacs can be abnormal and occasionally show precancerous changes. Having this condition increases your risk of getting gallbladder cancer in the future.

Doctors call an abnormality of the bile duct join with the pancreas an 'anomalous pancreatobiliary duct junction'. If you have this, it means that pancreatic juices and enzymes can go back up into the common bile duct. These digestive juices irritate and inflame the bile duct wall. Over time, this can weaken it. Scientists are still not sure whether the increased risk of gallbladder cancer is due to irritation from the pancreatic digestive juices or from bile stuck in the bile ducts for longer.

Gallbladder polyps
These small growths are not cancer. They develop on the surface lining of the gallbladder. But some may develop into cancer over a long period of time.

Obesity
Being very overweight can increase the risk of many types of cancers, including gallbladder cancer. Obesity means you are more than 40% over the maximum desirable weight for your height. In other words, if you should weigh 10 stone at most and you weigh over 14 stone, you are obese.

Being overweight causes changes in hormones in the body, particularly for women. It could be this change in the body’s hormone balance that increases the risk of gallbladder cancer. It has been estimated that more than one in ten cases of gallbladder cancer in men and almost one-third of cases in women are due to being overweight. There is information about the right weight for you in CancerHelp UK. And information on healthy eating on our news and resources website.

Diet
Diet is a difficult risk factor to prove and much more research needs to be done in this area before we can be sure how it affects our risk of particular cancers.

A diet high in carbohydrates and low in fibre may increase the risk of gallbladder cancer. A diet high in fresh fruit and vegetables seems to reduce the risk of many cancers, including gallbladder cancer. This may be because these foods contain high levels of the antioxidant vitamins A, C and E and other antioxidant chemicals. Vitamins and other substances in fresh foods may help to stop damage to the cells lining the gallbladder that can lead to cancer.

There is more about diet and the causes of cancer in the about cancer section of CancerHelp UK.

Race
The risk of developing gallbladder cancer is very different for people living in different parts of the world. For example, Israel has the highest rate of gallbladder cancer in the world. Native Americans in southwestern America are more likely to develop gallbladder cancer than in other parts of the USA. Other countries with significantly high rates are Mexico, Bolivia, Chile, and northern Japan. Low rates are found in India, Singapore and Nigeria.

Typhoid
Some research suggests that past infection with typhoid bacteria may mean you are more likely to develop gallbladder cancer than people who have never been infected. Doctors are still discussing whether this is an important risk factor. But these days typhoid is very, very rare in the UK. So in this country, it wouldn't be a significant risk factor anyway.

Hormone replacement therapy (HRT)
One research study has linked HRT to gallbladder cancer. We know that using HRT increases the risk of gallstones. But these researchers said they found women taking HRT had 4 times the risk of gallbladder cancer. The risk increased with longer use of HRT. But this is only one research paper. It is not possible to be definite about the risks of HRT after only one study. Although 3 times the risk sounds a lot, because gallbladder cancer is a relatively rare disease, 3 times that risk is still a small risk. You can read a summary of this study on the web.

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