Pancreatic cancer risks and causes
This page has information on possible risk factors for pancreatic cancer. You can find the following information
Pancreatic cancer risks and causes
Age - Pancreatic cancer is more common in older people. Almost half of all new cases are diagnosed in people aged 75 and over. It is uncommon in people under 40.
Smoking – This is known to increase your risk. Nearly 1 in 3 pancreatic cancers (about 30%) may be linked to smoking. Stopping smoking gradually reduces your risk to the same level as a non smoker.
Some medical conditions – Risk of pancreatic cancer is increased if you have a history of diabetes, long term inflammation of the pancreas (chronic pancreatitis), certain types of cancer or chronic hepatitis B infection. People with pancreatitis that runs in families (hereditary pancreatitis) also have an increased risk of pancreatic cancer.
Diet – Eating red meat may increase your risk of pancreatic cancer. Studies show conflicting evidence on whether high levels of saturated fat in your diet can affect pancreatic cancer risk.
Body weight and exercise – Being overweight causes an increase in the risk of pancreatic cancer. Doing physical activity may protect against pancreatic cancer.
Family history – Although this is not usually a factor, sometimes pancreatic cancer can run in families. There may be a genetic link in up to 1 in 10 cases of pancreatic cancer (10%).
You can view and print the quick guides for all the pages in the about pancreatic cancer section.
We don't really know what causes cancer of the pancreas. Around 8,800 people in the UK get pancreatic cancer each year. It is the 10th most common cancer, excluding non melanoma skin cancer. It is more common in older people. Almost half of all new cases are diagnosed in people aged 75 and over. Pancreatic cancer is uncommon in people under 40 years old.
Anything that increases your risk of getting a disease is a risk factor. Different cancers have different risk factors. Even if you have more than one risk factor it doesn't mean you will definitely get the disease. And just because researchers investigate a possible cause, that doesn't mean it will turn out to be a risk factor. Some factors can lower your risk of cancer and are known as protection factors.
Cigarettes, cigars, pipes and chewing tobacco all increase pancreatic cancer risk. A large Cancer Research UK study looking at lifestyle factors found that nearly 1 in 3 pancreatic cancers (about 30%) may be linked to smoking.
Cigarette smoke contains chemicals called nitrosamines. Nitrosamines are carcinogenic. They are found in some foods and drinks as well as in cigarette smoke. Scientists are not exactly sure why smoking affects pancreatic cancer risk, but they think it may be the nitrosamines.
Stopping smoking reduces the risk. It takes about 20 years after stopping smoking for the pancreatic cancer risk to fall to the same levels as those who have never smoked.
A meta analysis has shown that exposure to second hand smoke does not increase pancreatic cancer risk.
Studies in Scandinavia have shown that chewing snus (a type of smokeless tobacco) increases the risk of pancreatic cancer.
Risk of pancreatic cancer is increased if you have a history of
- Long term inflammation of the pancreas
- Pancreatitis that runs in families (hereditary pancreatitis)
- Stomach ulcer
- Helicobacter pylori infection
- Infection with hepatitis viruses
- Tooth or gum disease
Long term inflammation of the pancreas is called chronic pancreatitis. This condition increases the risk of pancreatic cancer, although overall it isn't responsible for a large number of cases. Chronic pancreatitis is most often caused by long term drinking of alcohol.
This is a rare condition, causing inflammation of the pancreas. It accounts for about 1 out of 100 cases of pancreatitis (1%). It is caused by a faulty gene that can be inherited from one parent. People with hereditary pancreatitis have a 50 times increase in risk of pancreatic cancer compared to the rest of the population.
Having a stomach ulcer is not generally linked to a risk of pancreatic cancer. But one study did find double the risk of pancreatic cancer in men with stomach ulcers.
People who have had an operation to remove some or all of their stomach in the last 2 years have an increased risk of pancreatic cancer. This increase may be because the cancers are picked up accidentally as a result of all the tests they have following the surgery. Bacteria growth following surgery may also play a role. The medicines people take for stomach ulcers are not linked with pancreatic cancer risk.
Helicobacter pylori (H pylori) is a bacteria that causes stomach ulcers, and is a known risk factor for stomach cancer. Some studies have shown that infection with H pylori increases the risk of pancreatic cancer. Millions of people are infected with H pylori and most do not get these types of cancer, and so there must be other factors at work.
People with diabetes have an increased risk of pancreatic cancer. Diabetes is a disease of the pancreatic cells that normally make insulin. It is possible that a growing cancer actually causes some cases of diabetes, rather than the diabetes causing the cancer. Pancreatic cancer specialists believe that anyone over 50 who develops diabetes and has unexplained weight loss should be investigated for other pancreatic disease, and to rule out pancreatic cancer. Most people who develop diabetes late in life are overweight, so diabetes and weight loss together are more unusual.
Remember - diabetes is a common disease. Even with the increased risk, the vast majority of people with diabetes will not develop cancer of the pancreas.
Long term infection of hepatitis B increases the risk of pancreatic cancer. Hepatitis C may also increase the risk, but the evidence for this isn't as clear.
Some research has shown an increased risk of pancreatic cancer in people who have tooth or gum disease. It is not clear why this is the case, though a type of bacteria which causes gum disease may play a role.
About 7 out of 10 cases of chronic pancreatitis are due to long term heavy drinking. Chronic pancreatitis is a known risk factor for cancer of the pancreas.
Some research suggests there may be a link between heavy drinkers and risk of pancreatic cancer. The risk is higher in people who drink 3 or more alcoholic drinks a day compared to those who drink less than 1 alcoholic drink a day.
People who have had certain types of cancer are at a higher risk of developing pancreatic cancer. These include digestive system cancers, pharynx cancer, cancer of the neck of the womb, lung cancer, womb cancer, breast cancer, ovarian cancer, bladder cancer, testicular cancer and kidney cancer. In some people the higher risk may be due to smoking but in other people it could be due to a genetic link or to radiotherapy treatment for the first cancer.
The links between diet and pancreatic cancer are still unclear.
We know from research that red meat may increase pancreatic cancer risk. A study showed that pancreatic cancer risk was higher in men who ate 120g red meat a day compared to those who ate no red meat.
Some studies show an increase in risk with large amounts of saturated fat in your diet. But other studies have shown no link.
A diet high in folate may reduce the risk of pancreatic cancer, but different studies have shown conflicting results. Folate supplements have not been shown to reduce the risk. Folate is found in leafy, green vegetables.
A meta analysis has shown that fruit and vegetable intake in adults is not linked to a reduced risk of pancreatic cancer.
Studies show that being overweight causes an increase in the risk of pancreatic cancer. A study has estimated that just over 1 in 10 pancreatic cancers (around 10%) in the UK in 2010 were linked to being overweight. This increase in risk could be because overweight people make more insulin. Insulin is a hormone made by the pancreas.
The World Cancer Research Fund say that physical activity may protect against pancreatic cancer. This link may be limited to people who do a lot of activity in their job (occupational activity) rather then recreational activity.
Sometimes pancreatic cancer is found to run in a family. This means there is a fault in a gene somewhere. There may be some genetic link in up to 1 in 10 cases of pancreatic cancer (10%).
Pancreatic cancer can be part of a family cancer syndrome, where an inherited faulty gene causes a number of different cancers to develop within the members of one family. There are many different types of family cancer syndromes.
People with 2 or more cases of pancreatic cancer in their family (on the same side), but no recognised gene faults, may have familial pancreatic cancer syndrome. The risk is higher if relatives were diagnosed before the age of 60.
You have an increased risk of pancreatic cancer if you carry the breast cancer gene fault BRCA2. You may have an increased risk with a BRCA1 gene fault, but the evidence is less clear. There is an increased risk for people with the bowel conditions FAP (familial adenomatous polyposis) and HNPCC (hereditary non polyposis colorectal cancer). And in some families with a tendency to have large numbers of unusual moles (Familial Atypical Multiple Mole Melanoma or FAMMM), which increases melanoma risk. Other rare syndromes that increase risk of pancreatic cancer are Peutz Jeghers syndrome and ataxia telangiectasia.
These are rare conditions. If one runs in your family, you are likely to know about it already. Most cases of pancreatic cancer are sporadic. That is, they do not run in families. So a genetic test would not help in these cases. Unless you know that your family has one of the particular gene faults mentioned above, having other types of cancer in the family is very unlikely to mean that you have an increased risk of cancer of the pancreas. A recent large study showed an increased risk of pancreatic cancer in people with a father, brother or son diagnosed with prostate cancer. But we need more studies before we can be sure about this.
Some research suggests that your risk of pancreatic cancer may be lower if you tend to have certain types of allergies such as eczema. It does not include food allergies or asthma. We don't know exactly why this is. It may be because your immune system is better at picking up abnormal cells. Or it may be to do with the effect of allergic reactions on the pancreas.
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