What are the risk factors for pancreatic cancer?
A risk factor is anything that affects your chance of getting a disease such as cancer. Different cancers have different risk factors. Some risk factors, like smoking, can be changed. Others, like a person’s age or family history, can’t be changed.
But having a risk factor, or even several risk factors, does not mean that you will get the disease. And many people who get the disease may have few or no known risk factors.
Researchers have found several factors that can affect a person’s chance of getting cancer of the pancreas. Most of these are risk factors for exocrine pancreatic cancer.
Risk factors that can be changed
Smoking is one of the most important risk factors for pancreatic cancer. The risk of getting pancreatic cancer is about twice as high among smokers compared to those who have never smoked. Scientists think this may be due to cancer-causing chemicals in cigarette smoke that enter the blood and damage the pancreas. About 20% to 30% of exocrine pancreatic cancer cases are thought to be caused by cigarette smoking. Cigar and pipe smoking also increase risk, as does the use of smokeless tobacco products.
Overweight and obesity
Being overweight is a risk factor for pancreatic cancer. Very overweight (obese) people are about 20% more likely to develop pancreatic cancer.
Carrying extra weight around the waistline may be a risk factor even in people who are not very overweight.
Workplace exposure to certain chemicals
Heavy exposure at work to certain pesticides, dyes, and chemicals used in metal refining may increase the risk of developing pancreatic cancer.
Risk factors that can’t be changed
The risk of developing pancreatic cancer increases as people age. Almost all patients are older than 45. About two-thirds are at least 65 years old. The average age at the time of diagnosis is 71.
Men are about 30% more likely to develop pancreatic cancer than women. This may be due, at least in part, to higher tobacco use in men, which raises pancreatic cancer risk (see above). The difference in pancreatic cancer risk was more pronounced in the past (when tobacco use was much more common among men than women), but the gap has closed in recent years.
African Americans are more likely to develop pancreatic cancer than whites. The reasons for this are not clear, but it may be due in part to having higher rates of other risk factors for pancreatic cancer, such as diabetes, smoking in men, and being overweight in women.
Pancreatic cancer seems to run in some families. In some of these families, the high risk is due to an inherited syndrome (explained below). In other families, the gene causing the increased risk is not known.
Inherited gene changes (mutations) can be passed from parent to child. These abnormal genes may cause as many as 10% of pancreatic cancers and can cause other problems as well. Examples of the genetic syndromes that can cause exocrine pancreatic cancer include:
- Hereditary breast and ovarian cancer syndrome, caused by mutations in the gene BRCA2
- Familial melanoma, caused by mutations in the gene p16/CDKN2A
- Familial pancreatitis, caused by mutations in the gene PRSS1
- Hereditary non-polyposis colorectal cancer (HNPCC), also known as Lynch syndrome, most often caused by a defect in the genes MLH1 or MSH2. Changes in other genes can also cause HNPCC, such as MLH3, MSH6, TGBR2, PMS1, and PMS2.
- Peutz-Jeghers syndrome (PJS), caused by defects in the gene STK11. This syndrome is also linked with polyps in the digestive tract and several other cancers.
- Von Hippel-Lindau syndrome, caused by mutations in the gene VHL. It can lead to an increased risk of pancreatic cancer and carcinoma of the ampulla of Vater.
Pancreatic neuroendocrine tumors and cancers can also be caused by genetic syndromes, such as:
- Neurofibromatosis, type 1, which is caused by mutations in the gene NF1. This syndrome leads to an increased risk of many tumors, including somatostatinomas.
- Multiple endocrine neoplasia, type I (MEN1), caused by mutations in the gene MEN1. This syndrome leads to an increased risk of tumors of the parathyroid gland, the pituitary gland, and the islet cells of the pancreas.
Changes in the genes that cause these syndromes can be recognized by genetic testing. For more information on genetic testing, see the section “Can pancreatic cancer be found early?”
Pancreatic cancer is more common in people who have diabetes. The reason for this is not known. Most of the risk is found in people with type 2 diabetes. This type of diabetes most often starts in adulthood and is often related to being overweight or obese. It’s not clear if people with type 1 (juvenile) diabetes have a higher risk.
In some people, though, the cancer seems to have caused the diabetes (not the other way around). This can happen when cancer spreads through the pancreas and damages enough of the insulin-making cells to cause diabetes.
Chronic pancreatitis is a long-term inflammation of the pancreas. This condition is linked with an increased risk of pancreatic cancer (especially in smokers), but most people with pancreatitis never develop pancreatic cancer.
A small number of cases of chronic pancreatitis are due to an inherited gene mutation. People with this inherited (familial) form of pancreatitis have a high lifetime risk for developing pancreatic cancer.
Cirrhosis of the liver
Cirrhosis is a scarring of the liver. It develops in people with liver damage from things like hepatitis and alcohol use. People with cirrhosis seem to have an increased risk of pancreatic cancer.
Infection of the stomach with the ulcer-causing bacteria Helicobacter pylori (H. pylori) may increase the risk of getting pancreatic cancer. Some researchers believe that excess stomach acid might also increase the risk.
Factors with unclear effect on risk
Some studies linked pancreatic cancer and diets that include a lot of red meat, pork, and processed meat (such as sausage and bacon). Others have found that diets high in fruits and vegetables may help reduce the risk of pancreatic cancer. But not all studies have found such links, and the exact role of diet in relation to pancreatic cancer is still being studied.
Some research has suggested that lack of physical activity might increase pancreatic cancer risk. But not all studies have found this.
Some older studies have suggested that drinking coffee might increase the risk of pancreatic cancer, but more recent studies have not confirmed this.
Some studies have shown a link between heavy alcohol intake and pancreatic cancer. This link is still not certain, but heavy alcohol use can lead to conditions such as chronic pancreatitis and cirrhosis, which are known to increase pancreatic cancer risk.
Last Medical Review: 06/11/2014
Last Revised: 06/11/2014