Causes and Risk Factors of Pancreatic Cancer

The exact causes of pancreatic cancer are not certain, but risk factors may include age, sex, race, genetic factors such as a family history of the disease, and lifestyle issues such as smoking, alcohol use, obesity, and even gum disease.

As symptoms of pancreatic cancer may not arise until it is advanced, it's important to be aware of how these factors may be influencing your own risk so can do what you can to reduce it and have informed conversations with your healthcare provider.

Common Risk Factors

Having a risk factor for pancreatic cancer does not mean that you will develop the disease. These factors do not always "cause" the disease, but rather are more common in people who develop it. Likewise, many people who develop pancreatic cancer do not have any obvious risk factors. That said, the more risk factors you have, the greater the likelihood you may face pancreatic cancer at some time in your life.

Risk factors may include:

Age

The risk of pancreatic cancer increases with age, though it is possible to be diagnosed at a young age. At the current time, around 90 percent of people are over age 55 at the time of diagnosis, with the average age at diagnosis being 71.

Race

Pancreatic cancer is more common in blacks than in whites, Asians, or Hispanics, but again, may occur in anyone. People of Ashkenazi Jewish heritage have an increased risk, most likely due to a high rate of BRCA2 gene mutations.

Sex

Pancreatic cancer was historically much more common in men than in women, but the gap is closing. The disease is now only slightly more common in men.

Diabetes

Long-term type 2 diabetes is a risk factor for pancreatic cancer. Diabetes may also occur shortly before the diagnosis, often in people who don't have risk factors for diabetes.

Gum Disease and Tooth Loss

Gum disease, referred to as gingivitis in the first stage and periodontitis in the advanced stage, was first noted to be a risk factor for pancreatic cancer in 2007.

The reason isn't known for sure, but it's thought that certain bacteria that live in the mouth make an enzyme that causes mutations in one type of gene (p53 gene mutations) that can lead to pancreatic cancer.

Chronic Pancreatitis

A history of chronic pancreatitis may increase the risk of pancreatic cancer, especially in people who smoke. Hereditary pancreatitis often begins in childhood and is associated with a much higher risk of the disease.

Other Medical Conditions

The bacterium Helicobacter pylori (H. pylori) is a well-known cause of stomach cancer, as well as peptic ulcer disease. It's thought that it may also increase the risk of pancreatic cancer. There is some evidence that hepatitis C infections, gallstones, gallbladder surgery, and cirrhosis of the liver may be linked with a higher risk of the disease.

Personal History of Cancer

People who have a personal history of several different types of cancer are more likely to develop pancreatic cancer. Researchers aren't certain if this is related to these other cancers in some way, or if the link is due to common risk factors for these cancers (such as smoking).

Blood Type

People with blood types A, B, and AB appear to have a higher risk of pancreatic cancer than those who have type O blood.

Chemical Exposures

Occupational exposures are thought to cause pancreatic cancers, with the chemicals of greatest concern being chlorinated hydrocarbons and polycyclic aromatic hydrocarbons (PAHs). Workers in which an increased risk has been noted include dry cleaning and female laboratory employees. 

Genetics

Roughly 10 percent of pancreatic cancers are considered to be hereditary and related to either a family history of the disease or a specific genetic syndrome.

Family History

People who have a family history of pancreatic cancer are more likely to develop the disease. There is also something referred to as familial pancreatic cancer. A person is considered to have this if two or more first-degree relatives (parent, sibling, or child) or three or more extended family members (aunts, uncles, cousins) have the disease.

Genetic Syndromes

Genetic syndromes linked to pancreatic cancer are often related to specific genetic mutations. Many of these gene mutations, such as BRCA2 gene mutations, are in genes known as tumor suppressor genes. These genes code for proteins that repair damaged DNA and limit the growth of cells. Syndromes associated with a higher risk include:

• Hereditary breast and ovarian cancer syndrome
• Hereditary pancreatitis
• Peutz-Jeghers syndrome
• Lynch syndrome (hereditary nonpolyposis colorectal cancer, HNPCC)
• Li-Fraumeni syndrome
• von Hippel Lindau syndrome
• Familial adenomatous polyposis
• Familial atypical multiple mole melanoma (FAMMM) syndrome
• Ataxia telangiectasia
• Multiple endocrine neoplasia type 1 (MEN1) syndrome (neuroendocrine tumors)
• Neurofibromatosis type 1 (neuroendocrine tumors)

Lifestyle Risk Factors

Lifestyle factors can play a significant role in the development of pancreatic cancer and include:

Smoking

Smoking increases the risk of pancreatic cancer two- to three-fold and is thought to be responsible for around a third of these cancers.

Alcohol

Long-term, heavy alcohol use (three or more drinks daily) is associated with an increased risk of pancreatic cancer. The risk may be related to an increased risk of pancreatitis in people who drink excessive amounts of alcohol (especially when combined with smoking) rather than the alcohol itself. Moderate alcohol consumption does not appear to increase the risk.

Obesity

Being overweight or obese raises the risk of pancreatic cancer around 20 percent.

Diet

There is some evidence that a high-fat diet, as well as a diet high in red or processed meat, may be associated with an increased risk of pancreatic cancer, especially when foods are cooked at high temperatures. On the other hand, foods high in folic acid, such as green leafy vegetables, may have a protective effect.

Sedentary lifestyle

A sedentary lifestyle, such as working a desk job, may increase risk, but it's uncertain at this time.