Risks and causes of gallbladder cancer
This page is about the possible causes of gallbladder cancer.
- A quick guide to what's on this page
- How common is gallbladder cancer?
- What is a risk factor?
- Gallstones and inflammation
- Family history of gallbladder cancer
- Porcelain gallbladder
- Primary sclerosing cholangitis (PSC)
- Smoking and chemicals
Risk factors for gallbladder cancer
Gallbladder cancer is a rare cancer in the UK. It is more common in women than in men. About 7 out of every 10 cases of gallbladder cancer are diagnosed in women. It is more common in older people.
Genetic factors and medical history
The most common risk factor for gallbladder cancer is having gallstones and inflammation of the gallbladder (cholecystitis). Having a first degree relative with gallbladder cancer increases your risk. Some rare abnormalities of the gallbladder that you are born with and having non cancerous growths called gallbladder polyps can also increase risk.
There are some lifestyle risk factors such as being overweight, smoking or working in the metal or rubber industry.
You can view and print the quick guides for all the pages in the about gallbladder cancer section.
We don't know the exact causes of gallbladder cancer. We know that it is a rare cancer in the UK, with around 660 cases diagnosed each year. Compared to more than 41,000 cases of bowel cancer each year, you can see how rare it is. Gallbladder cancer is more common in women than in men. About 7 out of every 10 cases diagnosed are in women.
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 may increase risk, but the evidence is not yet clear, such as hormone replacement therapy (HRT).
As with most cancers, gallbladder cancer is more common in older people than in younger people. There are very few cases in people under 70 years of age in the UK.
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.
One study has shown that a family history of gallstones doubles the risk of gallbladder cancer, and that people with a family history of gallstones who also have gallstones themselves have almost 60 times the normal risk of gallbladder cancer.
Remember that gallstones are very common but gallbladder cancer is very rare. Most people with an inflamed gallbladder or gallstones do not get gallbladder cancer.
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.
A study has looked at the increased cancer risk for people who carry the genetic mutation known as BRCA2. This mutation is known to increase the risk of breast and ovarian cancer. It also slightly increases the risk of gallbladder and bile duct cancer.
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 an inflamed gallbladder many times you may get porcelain gallbladder. If you have this condition, your doctor may suggest that you have surgery to take your gallbladder out.
Primary sclerosing cholangitis is a type of inflammation of the bile ducts. It is a rare condition and we don't know what causes it. People who have this condition have a slightly increased risk of developing cancer of the gallbladder.
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. Here is more about how smoking can affect your cancer risk.
Some abnormalities of the pancreas and bile duct increase your risk of getting gallbladder cancer. These include:
- Outgrowths along the bile duct (choledochal cysts - pronounced kol-eh-doke-al sist)
- An abnormality of the join between the bile duct and the pancreas
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 area where the bile duct joins 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 not being able to flow easily through the bile ducts.
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. The larger the polyp the greater that risk that it will become cancerous. You may have an operation to remove your gallbladder if you have a polyp that is larger than 1 centimetre (10mm).
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 a third of cases in women are due to being overweight. There is information about the right weight for you and information on healthy eating in our news and resources section.
A number of studies show you may have an increased risk of gallbladder cancer or cancer of the bile duct if you have diabetes. This is only a very small increase in risk.
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.
The risk of developing gallbladder cancer is very different for people living in different parts of the world, and for different racial groups. For example, north India has the highest rate of gallbladder cancer in the world. Other countries with significantly high rates are Israel, Chile, Ecuador and Pakistan. In the USA the black and Hispanic population has a greater incidence of gallbladder cancer than the white population. Native Americans in southwestern USA are more likely to develop gallbladder cancer than in other parts of the USA. Other countries with a higher rate of gallbladder cancer are Mexico, Bolivia, Korea and Japan. Lower rates are found in Singapore and Nigeria.
Salmonella infection can increase the risk of gallbladder cancer in people who have gallstones. There is strong evidence for this in Chile and North India. A few small studies show that Helicobacter pylori bacteria may also increase the risk of gallstone cancer.
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 it wouldn't be a significant risk factor here anyway.
Women who have increased exposure to the hormone oestrogen may have an increased risk of gallbladder cancer. For example a woman who has had 5 or more pregnancies is at greater risk. There is also some evidence that the birth control pill may slightly increase the risk of gallbladder cancer.
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, it is a small risk because gallbladder cancer is a relatively rare disease. You can read a summary of the HRT and gallbladder cancer study on the web.
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