Risks and causes
Doctors don’t know what causes most pancreatic cancers. But there are some factors that may increase your risk of developing it. Having any of these risk factors does not mean that you will definitely develop cancer. Around 9,600 people in the UK get pancreatic cancer each year. It is the 11th 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.
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. Support from free, local Stop Smoking services gives the best chance of giving up smoking.
Studies have given mixed results but using Scandinavian snus (a type of smokeless tobacco popular in Norway and Sweden) could increase the risk of pancreatic cancer .
Research has shown that exposure to second hand smoke doesn't increase your risk of pancreatic cancer.
About 7 out of 10 cases (70%) of chronic pancreatitis are due to long term heavy drinking. Pancreatic cancer is more common in people with chronic pancreatitis.
Some research suggests there may be a link between heavy drinkers and risk of pancreatic cancer. The results showed risk is higher in people who drink more than 6 units of alcohol a day compared to those who drink less than 6 units.
People who have had certain types of cancer are at a higher risk. These include:
- stomach cancer
- mouth cancer or cancer that starts in the voice box
- some female cancers - cervical, womb, ovarian or breast cancer
- bladder or kidney cancer
- testicular cancer
There may be a number of reasons for this. It might be:
- because of the same risk factors such as smoking
- due to a genetic risk
- due to previous cancer treatment
Having radiotherapy treatment for cancer in the past has been linked to an increased risk of pancreatic cancer. But this risk is balanced by the need to treat the original cancer.
The links between diet and pancreatic cancer are unclear. Some research has suggested a possible link between red or processed meat and pancreatic cancer.
A study showed that pancreatic cancer risk was higher in men who ate more red meat a day compared to those who ate no red meat. The same study also showed that both men and women who eat more processed meat have a higher risk of pancreatic cancer.
It is estimated that just over 1 in 10 pancreatic cancers (just over 10%) in the UK are linked to being overweight or obese. This increase in risk could be because the pancreas makes more insulin in overweight people. But we need more research to know for sure.
Physical activity may protect against pancreatic cancer.
Sometimes pancreatic cancer is found to run in families. But only between 5 and 10 in 100 of people (5 to 10%) diagnosed with pancreatic cancer have a family history of it.
Pancreatic cancer can be part of a family cancer syndrome, where an inherited family gene causes a number of different cancers to develop within the members of one family.
Your risk of pancreatic cancer is higher if you carry the faulty breast cancer gene BRCA2. There is also some evidence that having a BRCA1 gene fault could increase your risk of pancreatic cancer. But the evidence is less strong.
The pancreatic cancer risk is higher in people who have:
- Peutz-Jeghers syndrome
- Familial atypical multiple mole melanoma syndrome (FAMMM)
- Lynch syndrome/hereditary non-polyposis colorectal cancer (HNPCC)
These are rare conditions. You often know about it already if one runs in your family.
Remember, most cases of pancreatic cancer are sporadic, which means they don’t run in families.
Other medical conditions
The risk of pancreatic cancer is increased if you have a history of the following:
Long term inflammation of the pancreas is called chronic pancreatitis. It is most often caused by long term drinking of alcohol. There is a link between having chronic pancreatitis and developing pancreatic cancer, but isn't responsible for most cases.
Pancreatitis can also run in families (hereditary pancreatitis). It is a rare condition, causing inflammation of the pancreas. It accounts for about 1 in 100 cases (about 1%) of pancreatitis. A faulty gene that you inherit from one parent causes it.
People with hereditary pancreatitis have a 50 times higher risk of developing pancreatic cancer compared to the rest of the population.
This is a rare condition, causing inflammation of the pancreas. It accounts for about 1 out of 100 cases (1%) of pancreatitis. 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.
One study found double the risk of pancreatic cancer in men with stomach ulcers. But there is not enough evidence to say for sure if having a stomach ulcer increases your risk of having pancreatic cancer.
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 might be because the cancers are picked up as a result of all the tests they have had around the time of surgery. Bacteria growth following surgery may also play a role.
Helicobacter pylori (H pylori) is a type of bacteria that causes stomach ulcers. Some studies have shown that H pylori infection increases the risk of pancreatic cancer.
Worldwide millions of people are infected with H pylori and most people don’t have any health problems.
Diabetes is a disease of the pancreatic cells that normally make insulin. People with diabetes have an increased risk of pancreatic cancer.
It’s possible that a growing cancer actually causes some cases of diabetes, rather than diabetes causing cancer.
Some research studies has suggested that long term infection of hepatitis B is linked to and increased risk of pancreatic cancer.
Some research has shown an increased risk of pancreatic cancer in people who have tooth or gum disease. It is not clear why this may be the case, though a type of bacteria which causes gum disease may play a role.
Other possible causes
Stories about potential causes are often in the media and it isn’t always clear which ideas are supported by evidence. There might be things you have heard of that we haven’t included here. This is because either there is no evidence about them or it is less clear.
