Risks and causes of pancreatic cancer
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.
Anything that can increase your risk of getting a disease is called a risk factor.
Different cancers have different risk factors. Having one or more of these risk factors doesn't mean you will definitely get that cancer.
Around 10,300 people in the UK get pancreatic cancer each year. It is the 10th most common cancer.
The risk factors for pancreatic cancer include:
Pancreatic cancer 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.
Smoking and smokeless tobacco
Around 20 out of 100 cases of pancreatic cancer in the UK (around 20%) are caused by smoking. Cigarettes, cigars, pipes and chewing tobacco all increase pancreatic cancer risk.
The best way for people who smoke to reduce their risk of cancer and improve their overall health, is to stop smoking completely. The risk of pancreatic cancer in people who stopped smoking 20 years ago is the same as for people who have never smoked.
Being overweight or obese
More than 10 in 100 pancreatic cancers in the UK (more than 10%) are caused by 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.
Family cancer syndromes and genetic factors
Sometimes pancreatic cancer is found to run in families. But only between 5 and 10 in 100 people (5 to 10%) diagnosed with pancreatic cancer have a family history of it.
You have an increased risk if you have a
Pancreatic cancer can be part of a family cancer syndrome, where an inherited family
Your risk of pancreatic cancer is higher if you carry the faulty breast cancer gene BRAC1 and BRCA2. The evidence for the BRCA1 gene fault could increase your risk of pancreatic cancer. But the evidence is less strong.
Faulty breast gene PALB2 gene is also linked to an increased risk of developing pancreatic cancer.
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)
You often know about these conditions already if one runs in your family.
Other medical conditions
The risk of pancreatic cancer is increased if you have a history of the following:
Long term inflammation of the pancreas
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.
Rarely, pancreatitis can also run in families (hereditary pancreatitis). 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 higher risk of developing pancreatic cancer compared to the rest of the population.
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.
Gallstones are small hard lumps (usually of cholesterol) that form in the gallbladder. People with gallstones have an increased risk of pancreatic cancer compared to those without gallstones.
This may be because gallstones can cause chronic pancreatitis, which is another risk factor for pancreatic cancer. The increase in risk may only be for a short time after the diagnosis of gallstones. This may be due to the increased number of tests people have at this time.
Women with metabolic syndrome have an increased risk of pancreatic cancer compared with the general population. Metabolic syndrome is a group of symptoms including:
- having extra weight around the waist
- high blood sugar levels due to cells not responding properly to the hormone insulin (insulin resistance)
- high blood pressure
- high levels of fat in the blood
You can prevent or help reduce this group of symptoms by making changes to your lifestyle. This includes losing weight, eating a healthy balanced diet, cutting down on alcohol, exercising regularly, and stopping smoking.
Pancreatic cancer is more common in people with chronic pancreatitis. About 70 out of 100 cases of chronic pancreatitis (about 70%) are due to drinking high amounts of alcohol over a long time.
Some research suggests there may be a link between heavy drinking and the risk of pancreatic cancer. The results showed the risk is higher in people who drink 3 or more units of alcohol a day compared to those who drink less than 3 units. 3 units is about 1 pint (568mls) of 5.2% strength lager or 1 large glass (250mls) of 12% strength wine.
High energy radiation (ionising radiation)
Exposure to high energy radiation (x-rays or gamma rays) is linked to a very small increased risk of pancreatic cancer. This could be through medical tests such as x-rays and CT scans, or having radiotherapy for cancer.
The health risks of radiation from tests such as x-rays are generally very low and it is important you have these tests to get the right diagnosis and treatment. Doctors keep your exposure to radiation as low as possible and only do them when they are necessary.
Although having radiotherapy in the past has been linked with an increased risk of cancer, the risk is balanced by the need to treat the original cancer.
There is some evidence of a link between red meat and an increased risk of pancreatic cancer.
Currently, this increase in risk of pancreatic cancer seems to just be in men. This might be because women generally eat less red meat than men.
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.
Reducing your risk
There are ways you can reduce your risk of cancer.