Risk Factors for Pancreatic Cancer

Several risk factors for pancreatic cancer have been identified.  Some of these are modifiable, while others are not.

Modifiable Risk Factors

Cigarette Smoking: About one third of patients with pancreatic cancer have a history of smoking, and smokers are twice as likely to develop pancreatic cancer as people who do not smoke cigarettes. Smoking related cancers are more likely to be aggressive and often affect patients at a younger age.

Weight: Obesity is a known, but weak risk factor for developing pancreatic cancer.

Non-modifiable Risk Factors

Age: The risk of developing pancreatic cancer increases after age 50. Most patients are between the ages of 60 and 80 at the time of diagnosis.

Ethnicity: There is higher incidence of pancreatic cancer in Ashkenazi Jews, likely due to as of yet, unidentified genetic mutations present in individuals of this background. African Americans are also more likely to develop pancreatic cancer than are Asians, Hispanics, and Caucasians. The reasons for this discrepancy are not known.

Diabetes: Pancreatic cancer is two times more likely to occur in people who have diabetes than in people who do not have diabetes. However, the relationship between diabetes and pancreatic cancer is still not completely understood. It is not uncommon for individuals to develop diabetes before pancreatic cancer is detected and it may be that this glucose intolerance is actually caused by changes in the pancreas resulting from the cancer.

Chronic Pancreatitis: People diagnosed with chronic pancreatitis have an increased risk of developing pancreatic cancer. It is typically diagnosed in people who are 35-45 years old, and can be caused by several factors including alcohol, inherited anomalies of the pancreatic ductal system (pancreas divism), inherited genes (hereditary pancreatitis), or  trauma to pancreas.

Inherited Risk: Ten to fifteen percent of patients with pancreatic cancer will have a family history of the disease.  The relative risk of developing pancreatic cancer increases by 2-3 times in individuals who have a first degree relative (parent, sibling or child), who was diagnosed with the disease.  The risk increases if multiple family members are affected. In addition to these as of yet unidentified genetic factors, there are several inherited gene mutations that have been linked to an increased risk of pancreatic cancer.  Pancreatic cancer is associated with six distinct cancer syndromes, for which genetic testing is available.

The table below outlines these six syndromes, the responsible gene, and the relative risk (compared to the general population) of developing pancreatic cancer for an individual who harbors that genetic mutation. For example, if you carry the gene for familial polyposis, your risk of developing pancreatic cancer is five times greater than someone in the general population that does not have this genetic mutation.

 

Syndrome or Condition Mutated Gene Relative Risk of Developing Pancreatic Cancer
Hereditary Non-Polyposis Colorectal Cancer (HNPCC) MLH1, MSH2, MSH6 2x
Familial Polyposis APC 5x
Breast and Ovarian Cancer BRCA1, BRCA2 10x
Familial Atypical Multiple Mole Melanoma Syndrome (FAMMM) p16 15-65x
Hereditary Pancreatitis Trypsinogen 50x
Peutz-Jeghers Syndrome STK11 130x

Although the risk of developing pancreatic cancer is much higher for individuals with a family history of the disease or for individuals harboring one of these genes, the absolute risk of developing pancreatic cancer is still quite low.  The incidence of the disease among both men and women in the United States is only 12 per 100,000 people.  Additionally, many people who do develop pancreatic cancer do not have any of the conditions listed above.