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Pancreatic cancer risks and causes

Men and women discussing pancreatic cancer

This page has information on possible risk factors for pancreatic cancer. You can find the following information

 

A quick guide to what's on this page

Pancreatic cancer risks and causes

More than 8 out of 10 cases of pancreatic cancer (80%) are diagnosed in people aged 60 and over. It is uncommon in people under 40. There are some things that can increase your risk.

Smoking – This is known to increase your risk. Nearly 1 in 3 of pancreatic cancers (30%) may be linked to smoking.

Some medical conditions – Risk of pancreatic cancer is increased if you have a history of diabetes, long term inflammation of the pancreas (chronic pancreatitis), hereditary pancreatitis, stomach ulcers or certain types of cancer.

Diet – Eating processed meats may increase your increase your risk of pancreatic cancer. Studies show conflicting evidence on whether high levels of fat or sugar in your diet affect pancreatic cancer risk.

Body weight and exercise – Being overweight causes an increase in the risk of pancreatic cancer. And doing little or no physical activity in your job may increase the risk.

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%).
 

CR PDF Icon You can view and print the quick guides for all the pages in the about pancreatic cancer section.

 

 

How common pancreatic cancer is

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. More than 8 out of 10 cases (80%) are diagnosed in people aged 60 and over. Pancreatic cancer is uncommon in people under 40 years old.

 

Smoking and smokeless tobacco

Cigarettes, cigars, pipes and chewing tobacco all increase pancreatic cancer risk. 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. 

A large Cancer Research UK study looking at lifestyle factors found that nearly 1 in 3 pancreatic cancers (30%) may be linked to smoking. A large British study showed that people smoking up to 25 cigarettes a day have roughly double the risk of someone who has never smoked, while people smoking more than 25 cigarettes a day have three times the risk. 

Smokers with pancreatic cancer are diagnosed about 10 years younger than non smokers. Stopping smoking reduces the risk. Some studies show it can take between 10 and 20 years after stopping smoking for the cancer risk to be the same as for a non smoker. But a large European study showed that 5 years after stopping smoking, pancreatic cancer risk is the same as for a person who has never smoked. 

Some research has shown that exposure to secondhand smoke may also increase pancreatic cancer risk. Studies in Scandinavia have shown that chewing snus (a type of smokeless tobacco) increases the risk of pancreatic cancer. Researchers think that up to 1 in 5 cases of pancreatic cancer in Swedish men may be due to smokeless tobacco.

 

Other medical conditions

Risk of pancreatic cancer is increased if you have a history of

Long term inflammation of the pancreas

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 means having an inflamed pancreas over a long period. It is most often caused by long term drinking of alcohol, although this type of chronic pancreatitis is less likely to increase pancreatic cancer risk than other types of pancreatitis.

Pancreatitis that runs in families (hereditary pancreatitis)

This is a rare condition, causing inflammation of the pancreas. It is caused by a faulty gene that can be inherited from one parent. About 5 out of 10 of these people will have cancer of the pancreas before they are 75 years old.

Stomach ulcer

Having a stomach ulcer increases the risk of pancreatic cancer. This could be due to the types of bacteria that form in the stomach if you have an ulcer. They can produce cancer causing chemicals known as nitrosamines. People who have an operation for a stomach ulcer have double the risk of pancreatic cancer compared to the general population.

Diabetes

People with diabetes may have an increased risk of pancreatic cancer but their risk is still small. Diabetes is a disease of the pancreatic cells that normally make insulin. It is possible that a growing cancer 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. 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 possible increased risk, the vast majority of people with diabetes will not develop cancer of the pancreas.

Inflammatory bowel conditions

Ulcerative colitis and Crohn's disease are chronic bowel diseases. They both cause inflammation in the bowel. Having very severe ulcerative colitis or Crohn's disease for many years increases your risk of pancreatic cancer.

Tooth or gum disease

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.

 

Alcohol

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. But chronic pancreatitis that is due to alcohol doesn't increase risk as much as other types of chronic pancreatitis. 

Some research suggests there may be a link between heavy drinkers and risk of pancreatic cancer. But one study has shown no increase in risk in people who drink up to 4 to 5 units of alcohol a day (about 30 to 40 grams of alcohol). And another study has shown no increase in risk, even in people drinking more than 60g of alcohol (about 8 units) a day.

 

Previous cancer

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, bowel cancer, breast cancer, ovarian cancer, bladder 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.

 

Diet

The links between diet and pancreatic cancer are still unclear. Some research shows that you increase your risk if you have very high levels of sugar in your diet. But 2 studies have shown a lower risk for people with high sugar intake and 1 study showed no effect.

We know from research that processed meat may increase pancreatic cancer risk. Risk is increased by about one fifth (19%) for every 50 grams of processed meat you eat daily.  Processed meat means products such as bacon, ham and sausage meat. 50 grams is about one sausage or 2 rashers of bacon. The same research has also shown an increase in pancreatic cancer risk in men who ate 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.

There is occasionally talk about coffee drinking being linked to pancreatic cancer, but this has not been confirmed in research studies. Most experts do not think there is a link.

There is information about cancer and diet in the section about cancers in general.

 

Body weight and physical activity

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 (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. An analysis of published studies showed that the increase in pancreatic cancer risk only occurred in women and not men. We need more research to see if being overweight increases men's pancreatic cancer risk. 

Recent research studies have found no link between the risk of pancreatic cancer and levels of recreational physical activity. But people who have to do a lot of physical activity in their job have a lower risk of pancreatic cancer.

 

Family cancer syndromes and genetic factors

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. But there is not yet a genetic test available for pancreatic cancer. 

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 at least one first degree relative diagnosed with pancreatic cancer have almost double the risk of people without pancreatic cancer in their family.  People with two 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 or if there are more than two cases in the family.

You may have an increased risk of pancreatic cancer if you carry the breast cancer gene faults BRCA1 or BRCA2. 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.

 

Allergies

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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Updated: 14 January 2014