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 risk factors don't tell us everything. 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 not have had any known risk factors.
Researchers have found several factors that affect a person's chance of getting cancer of the pancreas. Most of these are risk factors for exocrine pancreatic cancer.
The risk of developing pancreatic cancer increases as people age. Almost all patients are older than 45. Nearly 9 in 10 are at least 55 years old and almost 7 in 10 are at least 65 years old. The average age at the time of diagnosis is 71.
Men are 30% more likely to develop pancreatic cancer than women. This may be due, at least in part, to increased tobacco use in men. 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 higher rates of smoking and diabetes in men and being overweight in women.
The risk of getting pancreatic cancer is at least 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. Quitting smoking helps lower risk – 10 years after quitting, former smokers have the same risk as those who never smoked.
People who use smokeless tobacco are also more likely to get pancreatic cancer.
Obesity and physical activity
Very overweight (obese) people are more likely to develop exocrine pancreatic cancer. Studies looking at the link between physical activity and the risk of pancreatic cancer have had mixed results.
Exocrine pancreatic cancer is more common in people who have diabetes. The reason for this link is not known. Most of the risk is found in people with type 2 diabetes. This type of diabetes most often starts in adulthood. It is often related to being overweight or obese. It is not clear if people with type 1 (juvenile) diabetes have a higher than average risk. In some patients, though, the cancer seems to have caused the diabetes (not the other way around).
Chronic pancreatitis is a long-term inflammation of the pancreas. This condition is linked with an increased risk of pancreatic cancer, but most patients with pancreatitis never develop pancreatic cancer. The link between chronic pancreatitis and pancreatic cancer is strongest in smokers.
A small number of cases of chronic pancreatitis appear to be due to an inherited gene mutation (see "Family history"). People with this inherited form of chronic pancreatitis seem to have a high lifetime risk for developing pancreatic cancer (about 40% to 75%).
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.
Heavy exposure at work to certain pesticides, dyes, and chemicals used in metal refining may increase the risk of developing pancreatic cancer.
Pancreatic cancer seems to run in some families. In some of these families, the high risk is due to an inherited syndrome (explained in the next section, "Genetic syndromes"). In other families, the gene causing the increased risk of pancreatic cancer is not known.
Inherited gene mutations are abnormal copies of certain genes that 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), most often caused by a defect in either the gene MLH1 or the gene MSH2. At least 5 other genes can also cause HNPCC: MLH3, MSH6, TGBR2, PMS1, and PMS2. This disorder is also known as Lynch syndrome.
- Peutz-Jeghers syndrome (PJS), caused by defects in the gene STK1. 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, 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 a genetic syndrome, 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 1, caused by mutations in the gene MEN1, leads to an increased risk of tumors of the parathyroid gland, the pituitary gland, and the islet cells of the pancreas.
Scientists have found the genes that cause the syndromes listed above and they can be recognized by genetic testing. For more information on genetic testing, see the section “Can pancreatic cancer be found early?”
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.
Some studies linked pancreatic cancer and diets high in fat, or those 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 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.
Last Medical Review: 01/28/2013
Last Revised: 09/06/2013